It plots the agricultural employment in Brazil, from 1960 to 2010, separately for different ten-years birth cohorts. Following a cohort of individuals as they age, we see that fewer and fewer of them work in agriculture: this suggests that the returns from agricultural production has decreased over time, thus pushing workers to reallocate. At the same time, if we compare across cohorts in any single year, we see that the younger ones have a smaller fraction of the workers in agriculture, suggesting that – due to their higher human capital – they have a stronger comparative advantage towards non-agriculture. Over time, higher human capital cohorts enter the labor market and replace lower human capital ones, thus contributing to an aggregate decrease in agricultural employment. Not all countries look like Brazil. As a comparison, in Figure 1b we plot a similar graph for India: in this case, within cohorts reallocation over time is mostly muted, while we still observe sizable across-cohort reallocation. In this paper, we systematically document this heterogeneity across countries, and exploit it to draw general conclusions on the role of human capital. More in general, however, the simple insight on the map between reallocation by cohort and human capital might fail, since cohorts possibly differ for aspects other than their human capital. In particular, younger cohorts may face lower mobility frictions to change sector. A core contribution of this paper is to develop a simple model to analytically characterize how the reallocation within and across cohorts can be used to back out the role of human capital, taking into account both mobility frictions and general equilibrium interactions across-cohorts. Equipped with the model, we use micro-level data for 52 countries to systematically document new facts on reallocation by cohort,square plastic planter along the lines of what just described for Brazil and India.

We then use data and theory together to back out the role of human capital and to show our two main results: human capital explains, on average, approximately one third of labor reallocation; but it does not explain why some countries have faster reallocation than others. We also show that mobility frictions play a minor role, which is instrumental in using reallocation by cohort to derive the main results. Finally, we turn back to schooling, and compare our approach with a direct measurement of human capital stocks using schooling. The two approaches are complementary.The paper is organized in four sections. In Section 2 we present a dynamic overlapping generation model. The model provides an accounting framework to leverage labor reallocation by cohort to quantify the relative role of human capital in aggregate labor reallocation out of agriculture. The general features of the model are the following: time is discrete; a finite number of cohorts are alive at each point in time; each period a cohort of individuals is born and enters the labor market and one dies; individuals are heterogenous in their human capital both within and across cohorts; average human capital grows across cohorts at a constant rate; there are two sectors: agriculture and non-agriculture; agriculture uses land and labor to produce; non-agriculture uses human capital; agricultural relative price and productivity, which give the relative revenue productivity, are exogenous and decrease at a constant rate; individuals choose, in each period in which they are alive, in which sector to work subject to two mobility frictions: a one time fixed cost to be paid to change sector, and an iceberg-type cost that reduces the monetary value of non-agricultural wage each period; markets are complete and competitive. We analytically characterize the equilibrium, which displays sorting across sectors, both within and across cohorts, and labor reallocation out of agriculture. We provide three sets of theoretical results. First, we show that the rate of labor reallocation out of agriculture is constant, does not depend on either mobility friction, and is increasing in the growth rate of relative non-agricultural revenue productivity, and in the growth rate of human capital across cohorts.

This result highlights the two core forces that lead to labor reallocation out of agriculture: decrease relative agricultural price and productivity; increase in human capital. Second, we decompose the rate of labor reallocation in two components: a year effect, which captures the rate at which a given cohort reallocates out of agriculture; and a cohort effect, which captures the gap in agricultural employment across cohorts. And we show that, absent mobility frictions and ignoring general equilibrium, the year effect pins down the relative contribution of prices/productivity, while the cohort effect pins down the relative contribution of human capital accumulation. This special case corresponds to our simple insight on the role of reallocation within and across cohorts. However, in general, mobility frictions and general equilibrium complicate the analysis, by tying together year and cohort effects. The theory provides further useful guidance: we show that only fixed costs are relevant to determine labor reallocation by cohort, and that old workers are more likely to be constrained by a fixed cost, since they have fewer periods to depreciate it over. As a result, comparison of labor reallocation rates across age groups informs us on the size of the frictions. Third, in search of additional ways to discipline the size of the mobility frictions, we describe how they affect the agricultural wage gap. We show that the wage gap for movers out of agriculture can be used to identify iceberg-type frictions – such as amenity costs that have to be paid each periods. However, we also show that fixed-cost-type frictions, which are the more relevant ones for our purpose, since they affect the map between cohorts effects and human capital, cannot cannot be inferred from wages. In fact, a small wage gap for movers out of agriculture is consistent with an arbitrarily large fixed cost. In Section 3 we turn to the data. In this section we describe three novel empirical results,leaving their interpretation through the lens of the model to Section 4. We use micro level data available from IPUMS international for 52 countries around the world. The data are either censuses or large sample labor force surveys representative of the population. For each country, we have at least two repeated cross-sections distant 10 years apart. On average, for each country there are 28 years from the oldest to the most recent cross-section. For some countries, such as Brazil, our data cover half a century of labor reallocation.

The 52 countries cover roughly 2 3 of the world population, and span five continents and the income distribution from Liberia to the United States. For each country, we compute year and cohort effects as defined in the model. On average, year and cohort effects are of similar size, thus giving our first empirical result: the across-cohortsreallocation accounts on average for approximately half of the overall labor reallocation out of agriculture. The year effects are strongly correlated with the rate of labor reallocation, while the cohort effects are more similar across countries, and less strongly correlated with the overall rate of reallocation. Formally, we decompose the cross-country variance of the rate of labor reallocation and show that differences in the across-cohorts reallocation explains approximately one quarter of it, which is our second empirical result. Finally, we compute for each country, the year effect separately for individuals of different ages, and show our third empirical result: individuals of different ages have similar year effects. Section 4 uses theory and data together to decompose, in an accounting sense, the relative roles of human capital and prices/productivity for labor reallocation out of agriculture. First, we show that, without taking a stand on the size of the frictions or the strength of general equilibrium,square plastic plant pot we are able to provide an upper bound to the relative contribution of human capital: the first empirical results above directly implies that human capital accounts for at most half of average labor reallocation. That is, absent human capital accumulation the average rate of labor reallocation out of agriculture could be as low as just half the observed one. Second, we use our theoretical results to infer a value for the mobility frictions, and thus be able to provide a point estimate for the role of human capital in partial equilibrium. To back out the size of the friction, we follow two different approaches. First, we use the prediction on reallocation rates by age: the third empirical result above is not consistent with sizable mobility frictions, which would imply that old individuals reallocate at slower rates. Second, we show that, under the assumption that the mobility friction is constant within a subset of countries, the second empirical result above is not consistent with sizable mobility frictions either: mobility frictions tie together the cohort and year effects, and thus would predict that countries with faster labor reallocation have both larger year and cohort effects. The data reject this hypothesis as well. Therefore, both approaches are not consistent with a large role for frictions. In fact, we show that, in partial equilibrium, human capital accumulation accounts for 37 − 56% of average labor reallocation, depending on the chosen estimate for the frictions. Third, an elementary calibration exercise suggests that the general equilibrium forces are unlikely to overturn the quantitative results: taking into account general equilibrium reduces the role of human capital accumulation to 19−52%. Using our favorite estimates for the size of the friction and for the GE calibration, we obtain that human capital accounts for approximately one third of labor reallocation out of agriculture. Fourth and last, we focus, rather than on the average rate of labor reallocation, on its variance across countries.

We show that, while human capital explains a sizable fraction of labor reallocation on average, it has at most a minor role in explaining why some countries have faster rate of labor reallocation than others. Finally, in Section 5 we turn back to the usual approach of the literature and exploit schooling as a direct measure of human capital. Using schooling is useful for two purposes. First, it allows us to validate the main empirical approach, by showing that our model-inferred human capital stocks align well with direct measurement through schooling, both in levels and in changes across cohorts. Second, using schooling enables us to provide a proof of concept on the possibility that policies designed to increase human capital can trigger labor reallocation out of agriculture. We follow closely Duflo and exploit the INPRES school construction program in Indonesia as an exogenous variation in schooling. We show that the exogenous increase in schooling decreased the agricultural employment of the affected cohorts.We draw upon insights from a rich literature on related topics. We here discuss our contribution relative to the most closely related articles. Our work builds on the seminal work of Caselli and Coleman II and Acemoglu and Guerrieri . To our knowledge, Caselli and Coleman II first recognized the interaction between aggregate changes in human capital and structural change. It noticed that non-agriculture is more skill-intensive than agriculture, and, therefore, an aggregate increase in schooling raises the relative supply of non-agricultural workers. It focused on the effect of human capital increase on relative wages, and argued that taking it into account is necessary to match the path of relative agricultural wages. Acemoglu and Guerrieri formalized the general insight that changes in the relative prices of inputs may lead to structural transformation if sectors vary in the intensity with which they use inputs. In its analysis, Acemoglu and Guerrieri considered capital and labor as the two inputs of interest. We owe to these two papers the broad notion that human capital accumulation may be relevant in explaining reallocation out of agriculture. Relative to their work, our contribution is to provide an accounting framework and to use reallocation by cohorts to separately account for the role of human capital relative to the role of relative agriculture prices/productivity . As discussed in the introduction, the recent literature that studies the cross-sectional allocation of heterogeneous workers to sectors motivates us to interpret human capital accumulation as a change in the relative supply of agricultural labor.At the same time, in our work we bundle together the traditional views of structural change that focus on demand or supply of agricultural goods, since they both similarly affect the relative revenue productivity of agriculture, hence the demand for agricultural labor.

The sorption improvements were attributed to NaOH breaking down the lignin encapsulating cellulose or hemicellulose, thereby increasing the exposure of cellulose for reaction. Creation of tiny fissures on the treated rice straw surfaces enlarged the surface area, thereby increasing ciprofoxacin retention via physical adsorption. In an analogous study, NaOH treatment of wheat straw increased sulfonylurea herbicide retention resulting in a maximum adsorption capacity as high as 337.22mg g−1 . Alkaline treatment increased both the surface roughness and functional surface activity due to hydrolysis of esters. These changes strengthened the interactions between the alkaline-treated straw and chlorsulfuron through H-bonding, ion exchange and complexation reactions. Notably, alkali treatment is operationally straightforward; however, excessive alkali concentrations should be avoided as excess alkali can degrade the functional group content as demonstrated for wheat straw .Acidification is a wet oxidation process that can remove mineral impurities from agricultural wastes and further improves the acidic behavior and hydrophilic nature of the adsorbent surface . Common reagents for acid modification include H3PO4, HCl, HNO3 and H2SO4. During treatment, acids dissolve constituents reducing the tortuosity of the porous structure and increase the O content of the material. In particular, acid treatment promotes cellulose hydrolysis of agricultural wastes creating a more reactive material . Tevannan et al. demonstrated that HCl reduced the mineral content of barley straw; Al, P, Mn, Cu and Zn concentrations decreased by 2.28%~9.80% after acid treatment. This reduction of mineral content contributed to increased adsorption of Ni2+ from solution due to decreasing competition among cations for adsorption sites.

Generally, lignocellulosic adsorbents have low adsorption capacities for anionic pollutants due to their negatively charged surfaces. However,25 liter pot case studies have demonstrated that acidification can improve the adsorption performance for anionic pollutants as well . They ascribed this phenomenon to HNO3 treatment promoting non-electrostatic interactions between adsorbent and adsorbate, such as van der Waals and H-bonding mechanisms. Dilute acids increase the amount of C-H, O-H and C-O groups on agricultural wastes. The main functional groups in modified rice straw after HCl treatment were O-H and C-O groups, which facilitated the adsorption of 2-chlorophenol . Concentrated acids can effectively convert hydroxyl and aldehyde groups to more oxidized groups, such as the carboxyl moiety. H2SO4-oxidized coconut shell had relatively high C and O contents due to the release of volatile compounds during acid oxidation . The surface of the treated material was surrounded by COO− and SO3 − groups, which were highly effective for the adsorption of methylene blue. Further, the O content of HCl- and HNO3-treated agave bagasse increased by 4.9% compared with the raw material due to an increase of carboxyl groups . Notably, concentrated acid oxidation was shown to decrease the surface area of oxidized coconut shell due to strong corrosion, which may reduce the porosity and efficacy of the adsorbent material for retention of some pollutants . Several studies have demonstrated the efficacy of acid treated agricultural wastes for heavy metal ions, such as Zn2+, Pb2+ and Cr6+ . Acid treatment alters functional groups and several surface area/porosity characteristics to enhance adsorption performance . The adsorption capacity of natural corncob for Cd2+ increased from 4.7 to 19.3mg g−1 when the material was acidifed by HNO3 . The Cd2+ was adsorbed mainly by the carboxylic sites through ion exchange and the adsorption capacity increased directly proportional to the concentration of carboxylic sites. Te glycosidic bonds of cellulose and hemicellulose are broken down to produce aldehyde groups and eventually carboxylic groups during acidic modification.

Similarly, the maximum Cu2+ sorption capacity of HNO3-treated corn cob was 3-fold higher than that of the raw corn stalk . The pHPZC for modified corn stalk was 3.3, which was lower than that of untreated material due to the increase of O-containing groups. The acid-modified adsorbent also showed a lower separation factor than raw corn stalk , Acid-treated agricultural wastes are also effective for removal of several organic pollutants. Attainment of adsorption equilibrium for Basic Red 18 and methylene blue by HNO3- and H3PO4-modified oreganum stalks was much shorter than that of the corresponding non-treated stalks . The more rapid kinetics were ascribed to increased surface area and reactive functional groups after acid treatment, which created enhanced electrostatic and hydrophobic interactions between adsorbents and adsorbates . The results showed that the maximum adsorption of Victazol orange 3R dye to dilute HCl-treated mango seed increased from 36.9 to 63.3mg g−1 with much faster sorption kinetics than the untreated seeds owing to increased BET surface area and average pore diameter . Overall, acid treatment contributes greater functional group reactivity and structural properties to enhance adsorption performance.Esters are generated from the esterification of free hydroxyl groups in cellulose by reacting with one or more carboxyl groups , whereby cellulose reacts as a trivalent polymeric alcohol . Succinic anhydride, EDTA dianhydride, citric acid anhydride and maleic anhydride are widely used for esterification reactions, thereby adding functional groups to the surface of agricultural wastes. In addition, the hydrophobicity and mechanical strength of adsorbents are improved by esterification as well . These beneficial changes from esterification contribute to enhanced adsorption performance of agricultural wastes for application in remediation of aqueous systems. Crop straws are widely used as a feedstock for esterification treatment. For instance, soybean straw and citric acid were mixed at a solid:liquid ratio of 1:10 and reacted at 50°C for 24h and 120°C for 90min to prepare an esterified adsorbent . After modification, a strong stretching vibration at 1742 cm−1 occurred in the FTIR spectrum, indicating a successful esterification process . The -OH of cellulose reacted with citric acid to form ester linkages and imparted carboxyl groups onto the straw surface.

With regard to the adsorption mechanisms, the carboxyl groups introduced by citric acid reacted with Cu2+ via a complexation reaction. Similarly, the etherification procedure was adopted to prepare esterified rice straw using EDTA as a modifying agent. The EDTA etherification processes generated both amino groups and carboxyl groups as adsorbents . The relative peak shifts and signal strength alterations of FTIR spectrums revealed the combined actions of carboxyl, ester and amine groups of the grafted EDTA in Pb2+ binding. Additionally, some studies determined that the carboxyl esterification not only introduced more carboxyl groups on wheat straw, but also roughened the surface, thereby increasing surface area and porosity . As a result, the increased -COO− content and porous surface properties enhanced methylene blue sorption through improved ion exchange and intraparticle diffusion. The type of esterification reagent strongly affects the adsorption properties of agricultural wastes. For example, citric acid modified sesame straw fixed more methylene blue than that formed by tartaric acid modification . The contrasting effects of these two reagents were attributed to differences in their molecular structures. Citric acid possesses more carboxyl groups than tartaric acid, which resulted in generation of more adsorption sites following citric acid treatment than for tartaric acid treatment . The FTIR spectrum of the modified materials confirmed a large increase in the intensity of the C=O stretching peak resulting from citric acid treatment. Catalyst addition could further promote the esterifcation efficiency during modification. The esterification between citric acid and hydroxyl groups achieved in high efficiency using a mild catalyst in a N, N-dimethylformamide medium , NaH2PO2·H2O, as a catalyst, increased the speed of the esterification reaction and allowed for a simplified procedure compared to traditional methods without catalyst. Te catalyzed process created ester linkages within the spent grain complex and increased carboxylic acid groups on the adsorbent surface. Several studies demonstrated improved adsorption performance for pollutants following esterification of agricultural wastes . Adsorption of Cu2+ by citric acid modified soybean straw was rapid during the first 10min and reached a maximum adsorption capacity of 0.69 to 0.76mmol g−1 based on a Langmuir model . The adsorption mechanism also changed due to the increase of functional groups. The biosorption energy of citric acid modified barley straw for Cu2+ adsorption was 8.513kJ mol−1 , indicating a chemical adsorption mechanism,25 liter plant pot as opposed to a physical adsorption mechanism for the raw biomass . Similarly, Pb2+ adsorption capacity increased from 125.84mg g−1 to 293.30mg g−1 due to the formation of both ester linkages and grafting of carboxyl groups . For organic pollutants, the intensity of chemisorption was closely related to the number of functional groups. Methylene blue adsorption capacity increased from 170mg g−1 to 650mg g−1 and 280mg g−1 . The larger methylene blue adsorption capacity for the citric acid treatment was due to a larger increase of C=O in carboxyl groups, which interacted with methylene blue via complexation. In general, carboxyl and amino functional groups are the most common groups introduced onto adsorbents by esterifcation, which consequently improve adsorption performance through complexation reactions.Ethers are synthesized through etherification, whereby -OH groups on agricultural wastes are substituted by other functional groups .

Reaction of -OH groups with ethylene oxide or other epoxides is a typical etherification reaction yielding several reactive sites for further functionalization to introduce adsorption groups. Triethyleneteramine, diethylenetriamine and ethylenediamine are usually used to generate amine groups for adsorbents during the functionalization process. Generally, carboxyl, thio and amino functional groups are introduced to the biomass surfaces by the etherification process . Etherification may generate positively-charged functional groups to augment sorption sites for retention of anions, such as PO4 3−, NO3 − and SO4 2− . The interaction between epichlorohydrin and -OH groups of agricultural wastes is a common etherification process to generate new functional groups. For example, epoxy and amino groups were introduced onto raw rice straw by reaction between epichlorohydrin and trimethylamine . An FTIR peak associated with the C-N bond at 1470 cm−1 and a peak for quaternary ammonium salt at 1062 cm−1 appeared on the surface of rice straw following modification, thereby indicating generation of positively charged amino groups. This etherification process increased the total exchange capacity of the adsorbent from 0.32 to 1.64mEq g−1 and rapid adsorption of sulfate via an ion exchange mechanism. Similarly, ethylenediamine-cross-linked wheat straw was utilized to introduce amine groups for use in removing HCrO4 − and H2PO4 − from solutions . Although the BET surface area of the modified biomass decreased from 6.5 to 5.3 m2 g−1 , the modification process increased the quantity of positive charge. After modification, the zeta potential of the modified wheat straw was in the range of +39.3~−7.0mV compared with +5.2~−45.8mV for the raw wheat straw. The higher zeta potential for the modified material was attributed to the presence of -CN+, which possessed a stronger electrostatic attraction for anionic pollutants. Several studies have documented the efficacy of etherification for increasing the reactivity of agricultural wastes for retention of anionic pollutants through electrostatic interactions . Etherifcation processes are also utilized to improve the removal rate of cationic pollutants by introducing amino groups for modified adsorbents. Kong et al. introduced amino and carboxyl groups on the surface of wheat straw to investigate Cu2+ sorption behavior. They found that the introduced -NH2 groups shared their lone pair of electrons to form R-NH2Cu2+ complexes as the adsorption mechanism. Moreover, the introduced -COOH groups facilitated charge transfer to the O to attract the Cu2+, thereby further promoting Cu2+ retention. Etherification can also generate thio groups on adsorbents to attach cationic pollutants. Moreover, ethylenediamine and CS2 treatment generated S-containing functional groups on sugarcane bagasse, which played an important role in adsorbing Pb2+, Cu2+ and Zn2+ . Characterization of the etherification product indicated formation of -S=metal bonds formed through coordination bonds with the S atom in the biosorbent owing to the lone pair of S electrons sharing a bond with the metal. A summary of etherification modified agricultural wastes as adsorbents for the removal of pollutants from aqueous solution were presented in Table 4. The maximum Cu2+ sorption capacity of etherified wheat straw cellulose reached up to 130mg g−1 , which were attributed to complexation reactions of Cu2+ with the amino and carboxyl groups generated by etherification . Additionally, adding an activated bond of -CN to the cellulose -OH groups greatly improves Cd2+ adsorption performance . The Langmuir sorption model provided a better ft to the Cd2+ adsorption equilibrium data than a Freundlich model, and determined a maximum uptake of 12.73mgg−1 for modified corn stalks, compared to 3.39mg g−1 for raw corn stalks.

Soil carbon declined from 55 to 19% and microbial biomass by up to 50% for the different treatments over the 4-year period. Microbial biomass was also strongly correlated with SOC. Hence, this study provided a unique opportunity to evaluate if different microbial taxa were more sensitive to this major carbon resource shift and to determine if crop and/or management practice altered the microbial community over the relatively short time period. We used pyrosequencing of the SSU rRNA gene to determine community structure as it provides sufficient information depth so that community responses could be quantified under the contrasting soil management schemes.After four years, microbial communities in Ghanaian soil responded to the different managements with detectable changes in their diversity and composition. The overall microbial community diversity was higher for all agricultural managements than in the elephant grass eshrub dominated unmanaged plot . Bacterial groups that were responsive to particular treatments were additions to the endogenous community found in Eu. These groups are likely part of the “rare biosphere” in the Eu community but respond to the new selection provided by the new managements. Physical disturbance of the soil under these managements due to plowing, planting, and burning of fallow plants may induce more community dynamics, including resource competition. In terms of species richness, the lowest diversity was found in BF, which was likely due to very low carbon inputs. Even though fertilizer application led to the highest carbon input due to organic residue deposition , microbial diversity was relatively lower in the EfM plot, both in terms of richness and evenness. This is likely due to the higher nutrient availability, driving a less metabolically diverse r-selected community. Conversely, the PM management sequestered some carbon as woody biomass derived from high lignin content in pigeon pea. providing more aromatic residues and slower nutrient release, as well as added N from its N2-fixation capabilities. Based on these results,black plastic planting pots and supported by previous T-RFLP analysis , pigeon pea appears to be an appropriate cover crop for the fallow period in tropical agricultural systems by fostering a diverse microbial community while also maintaining SOC and supplying nitrogen. Soil microbial community structure and specific taxa distributions were found to be most affected by SOC. Sequestered carbon appeared to largely influence Actinobacteria and Acidobacteria abundance in soil.

The low-SOC BF treatment consistently exhibited the highest abundance of Actinobacteria, mostly of the subclass Rubrobacteridae. Previously isolated bacteria within this subclass, Rubrobacter and Thermoleophilum , are resistant to radiation and are found primarily in arid soil, which is consistent with the harsh exposed soil condition due to the meager summer maize crops in last two experimental years . It does not appear that all Acidobacteria groups uniformly respond to the same environmental variables, especially SOC. This is not unexpected for this very large, diverse and understudied phylum. Acidobacteria Gp4 and Gp6 were present in higher abundances in the nutrient-enriched plots than Acidobacteria Gp1 and Gp7 , even though Acidobacteria are thought to be oligotrophs. Network analysis also supported a positive correlation between SOC and modules containing Acidobacteria Gp4 and Gp6. Previously, the abundance of Acidobacteria groups was correlated to soil pH , with Acidobacteria Gp1 and Gp3 abundance largely positively correlated to acidity while Gp4, Gp5, Gp6, and Gp7 correlated to alkalinity when soils within the ranges of 4.5e8.3 were tested . Also, wheate soybean rotation was associated with the higher Acidobacteria Gp4 abundance than continuous wheat management while Gp1 abundance was the opposite . This is also explained by a difference in soil pH of different crop rotations: wheate soybean rotation and continuous wheat management . However, our soils were within pH 6e6.9 ; as such, pH does not appear to be a significant factor in this study. Our soil exhibits lower SOC than the general range of global SOC, a narrower pH range and no cold or freezing stresses. Thus, the abundance of Acidobacteria groups in our study can provide insight into understanding the ecophysiology of the Acidobacteria phylum in low SOC and near neutral pH environments. Burning of residues produces measured soil temperatures in topical soils of 200e800 ” C at 0.5 cm and 100e200 ” C at 2.5 cm depths . Soil temperatures of 120 ” C and 250 ” C have been shown to be lethal to 34e80% and 85e99%, respectively, of the microbial biomass . Although temperature was not measured in this study, the higher proportion of Bacillales, especially genera Bacillus and Sporosarcina, in the burned plots was notable. It may be due to the heat resistance of these spore-forming bacteria. Sporosarcina spp. not only tolerates high temperature, but also grows at 50 ” C .

Our core samples were taken over the top 18.5 cm so the effect of burning was probably muted by the populations at the lower depths unaffected by temperature. The fact that we could see any effect, however, suggests that burning was selective on the resulting community. Carbon is the key resource supporting most terrestrial microbial communities. Its decline due to cultivated agriculture in temperate region soils is much slower. In tropical systems, however, the continuously warmer temperatures and where moisture is suffi- cient and perhaps cultivation occurs, there is a faster loss of organic carbon. In this study the soil carbon declined by up to 55% in only 4 years. This loss plus the lack of significant annual resupply of available carbon by plants especially in years 3 and 4 of the bare fallow treatment would be expected to be a major perturbation to the microbial community, and did show a loss of 50% of the microbial biomass . We found a significant but not dramatic change in the microbial community structure, suggesting that the community as a whole is rather resistant to this even more extreme decline in its food sources.Because of the employment opportunities and economic multipliers it creates, especially during the early stages of development, agriculture has long been at the center of discussions about poverty reduction and economic development . Increasingly, so are its related up- and down-stream activities in input supply, food logistics, food processing, retail, and food services, which, together with agriculture, make up the broader agri-food system . The AFS remains a major employer, particularly in poorer countries and for the poorer segments of society . Much hope is vested in the AFS to create badly needed jobs for youth in Africa, as well as for vulnerable populations and people in lagging regions elsewhere in the world . In contrast, employment in the AFS has dropped to only 10 percent of the labor force in high income countries, where the majority of AFS jobs are now off-farm in food processing and services. There, the domestic workforce has shifted out of the AFS. New digital technologies are enabling the automation of some historically labor-intensive agricultural tasks and providing an alternative to domestic labor substitution through international migration. COVID-19 will likely reinforce these trends. Given these developments, what role will the AFS play in the future of inclusive job creation across different countries worldwide? At the early stages of development, employment in the AFS largely coincides with employment in farming.

A large share of the population lives in rural areas and engages in subsistence production. Food supply chains are short and, for the most part, local. As countries develop, however, populations urbanize and food supply chains become longer. The income elasticity of demand for food declines, agriculture’s role as employer diminishes ,drainage pot and the farm workforce becomes older, more wage-oriented, and more immigrant.1 Urban consumers, and those with rising incomes, demand foods that are more protein- and nutrient-rich, processed, and convenient to consume. This change in demand provides some scope for agriculture related job creation beyond the farm, particularly in food processing and services. While these changes occur, jobs on the farm typically become more remunerative and competitive with jobs off the farm even though they dramatically shrink in terms of share and number.2 These dynamics, driven importantly by food demand behavior, have been observed across countries throughout history. They are broadly known as the structural transformation and the agricultural/dietary transformation . Often, these transformations are accompanied by deeply wrought societal change in response to growing rural-urban income divides and ineffective policy responses, including agricultural protectionism, especially when investment in rural public goods and inclusive food value chain development lags behind . Technological revolutions further shape these dynamics . Examples include steam power, railways and tractors in the 19th century, and electricity and cold storage in the 20th century. The current century is witnessing a rapidly unfolding digital revolution , with another revolution in energy just around the corner . These technological advancements of the 21st century and the associated business and product innovations are affecting structural and agricultural transformations across the globe. They have the potential to profoundly alter the global organization of the food system, as well as labor and skill demands. They dramatically reduce transaction costs in input and output markets, change economies of scale, and modify the optimal capital/labor mix in agricultural production, processing, and marketing. Because some agricultural tasks are arguably more automatable than those in industry and services , automation could accelerate the exit of labor out of agriculture in developing countries and transform farms and food processing firms in the developed world. A future with robots in the fields and packing plants, together with technology-savvy farm workers to complement new technological solutions in specific commodities and tasks, already is taking shape. Solar driven water pumps , cold storage, and agro-processing equipment are also beginning to spread in rural India and East Africa, accelerating the transition away from subsistence production . Historically, during this process of structural and agricultural transformation, societies typically evolved from having a surplus to a shortage of domestic farm labor. Inefficient land markets and sluggish food value chain development slowed farm consolidation and diversification, and social protection for the self employed remained limited.

As a result, farm incomes have struggled to keep up with more secure and faster-growing incomes off the farm. Domestic workers shifted from the primary sector to the secondary and tertiary. More often than not, in developed countries farm labor shortages have been filled largely by foreign agricultural wage workers, especially for difficult-to-automate tasks like harvesting fresh fruits and vegetables. Migrant-sending households in low-income countries benefited through remittances. However, with anti-immigration sentiments flying high in migrant-destination countries, the structural transformation unfolding in migrant-source countries, and technology increasingly offering alternatives to hired labor everywhere, opportunities to close income gaps across countries through legal farm labor migration may be narrowing . The shift in policy dialogue away from immigration solutions to farm labor problems coexists with a bifurcating global demographic. Many developing countries, especially in Sub-Saharan Africa, struggle to provide employment for their young, rapidly-expanding populations, presenting a missed opportunity for development from the so-called “demographic dividend” , including through international migration. Agricultural trade is similarly challenged in its role to help address global imbalances in farm labor, partly because of its purported contribution to global warming. The domestic and global forces of structural transformation and food demand behavior, the new technological revolution and associated business innovation, and the deceleration of agricultural trade and labor migration provide much of the socioeconomic backdrop against which the future of work in the AFS unfolds across countries. These transformations are further affected by the recent COVID-19 pandemic. It already has set back income growth . In the long run, the pandemic will reinforce existing trends in AFS automation and digitization and decrease reliance upon agricultural labor migration and trade, especially in the developed world. The pandemic has also exposed vulnerabilities in supply chains, as some countries experienced difficulty securing supplies of strategic goods and risks ushering in a new wave of protectionism .How countries address these, and related, challenges will shape the extent to which the AFS can continue its historically crucial role in reducing poverty and fostering shared prosperity by raising smallholder incomes and creating employment opportunities for young, expanding work forces. We argue that a policy and business environment supportive of inclusive agricultural value chain development will be a critical component of the solution. Adequate competition policies to address the challenge of rising power concentration within the AFS need to be part of the solution, as does the provision of broad access to digital infrastructure.

Snakins isolated from Solanum tuberosumare cysteine-rich peptides roughly 6.9 kDA in size and the snakins isolated from potato tubers is effective at suppressing both fungal and bacterial growth at concentrations lower than 10 μM. Transgenic potato plants overexpressing the StSN1 gene exhibited reduced symptoms of R. solani infections and higher survival rates compared to the wild type plants . Additionally, StSN1 has been shown to be effective in vitro against B. cinerea and several Fusarium species.However, snakins have been rarely expressed successfully from microbial hosts, often with low yield and insolubility, which hinders in-depth mechanistic characterization of its action towards pathogenic fungi . Another promising group of AFPs are the puroindolines, which are small, amphipathic tryptophan-rich proteins about 13 kDA in size and found only in wheat . They are known to inhibit the growth of pathogenic bacteria and fungi with low mammalian toxicity, likely through strong binding with microbial membranes and therefore perturbing the membrane integrity. These proteins are believed to protect seeds from fungal attacks during seed development and germination. There are two major puroindolines, Puroindoline A and B. When the pin genes are over expressed in transgenic rice, rice displayed significantly enhanced resistance to rice blast caused by Magnaporthe grisea and a reduction in symptoms due to Rhizoctonia solani infections . Purified PINA and PINB proteins from wheat were able to inhibit the growth of a variety of pathogenic fungi, including Alternaria brassicola, Ascochyta pisi, F. culmorum, F. graminearum, Magnaporthe girsea, R. solani, and Verticillium dahlia. PINA and PINB are stable over a broad range of temperature and pH. PINs have been heterologously produced in Pichia pastoris with a titer up to 14 mg/L taking advantage of puroindoline’s solubility in the detergent Triton X-114 . These various AFPs discussed highlight the potential of using AFPs as anti-fungal agents for agricultural purposes. In the past decade,vertical tower for strawberries there has been an increase in interest towards proteins containing domain of unknown function for their capability in fighting plant pathogens and especially fungi .

DUF26 is a cysteine rich domain with a conserved C-X8-C-X2-C motif. DUF26-containing proteins are a large, land plant-specific protein family and characteristic of embryophytes . Similarities with fungal lectins suggests DUF26-containing proteins constitute a group of plant carbohydrate-binding proteins able to recognize specific fungal sugar motifs. There are three groups of DUF26-containing proteins: the cysteinerich receptor-like secreted proteins , cysteine-rich receptorlike kinase and plasmodesmata-localized proteins . The three DUF26-containing protein groups were all previously associated with anti-fungal activities. Nevertheless, only CRRSPs remain as good candidates for biotechnological application since CRKs and PDLPs contain transmembrane domains and localize to the membranes. CRRSPs contain a signal peptide followed by one or more DUF26 domains, separated by a variable region. The most well-known CRRSP is Ginkbilobin2 , which was isolated from seeds of Ginkgo biloba and able to inhibit the growth of F. oxysporum, T. reesei, and C. albicans. This anti-fungal activity is likely due to the binding of DUF26 domain with sugar moieties on the fungal cell wall . For instance, Gnk2 interacts specifically with mannan, a yeast cell wall polysaccharide, and mannose, a building block of mannan, by strictly recognizing the hydroxy group at the C4 position of the monosaccharide. Consistently, two maize CRRSPs have been characterized to interact directly with the hyphal surface of Ustilago maydis, and the activity can be rendered by Rsp3, a U. maydis effector covering its surface . In addition to direct binding with fungal cell walls, DUF26- containing proteins from CRRSP family also protect plants using indirect mechanisms. CRR1, a secreted apoplastic protein from cotton, and composed of two Cys-rich DUF26 motifs, interacts and protects the anti-fungal apoplastic chitinase 28 from cleavage by VdSSEP1, a pathogen related protease. Importantly, over expressing CRR1 in heterologous plants such as Arabidopsis thaliana and Nicothiana tabacum improved plant resistance to B. cinerea and P. parasitica, respectively. Thus, CRR1 could be a good candidate as a co-anti-fungal agent and simultaneous exogenous application of CRR1 and chitinases should be evaluated. Another CRRSP of interest is the recently reported CBM1-interacting protein in rice.

Pathogenetic fungi generally use cell wall degrading enzymes to destruct plant cell walls, and many CWDEs use carbohydrate binding modules to facilitate the access to plant polysaccharides to advance the infection process . OsCBMIP can specifically bind to CBM of several CBM-containing CWDEs including the xylanase MoCel10A of the blast fungus pathogen Magnaporthe oryzae and slow down the infection progress. Interestingly, OsCBMIP cannot inhibit the growth of M. oryzae and F. oxysporum in vitro, and this further indicates that OsCBMIP slows down the infection of pathogenetic fungi through indirect mechanism, here specially, through inhibiting CBM-containing CWDEs. In another study, a transcriptomic analysis of wheat after Bipolaris sorokiniana or Rhizoctania cerealis infection reported the induction of a cysteine-rich protein , TaCRR. When heterologously expressed, this DUF26-containing protein showed a clear anti-fungal activity. Besides, it was found that silencing TaCRR gene in wheat significantly decreased the expression of pathogenesis-related genes such as β-1,3-glucanase, defensin or chitinases. Owing to their apoplastic localization and direct or indirect anti-fungal activities, DUF26-containing proteins from the CRRSP class remain as attractive candidates for the future development of anti-fungal agents. Polygalacturonase inhibiting proteins are a family of leucine rich repeat proteins found in plant cell walls whose primary role is to inhibit polygalacturonases , enzymes secreted by insects and fungal pathogens that degrade the plant cell walls and leave it vulnerable for infection . Through competitive or noncompetitive inhibition, PGIPs slow the hydrolysis process of PGs . Presently, numerous studies show that overexpression of PGIPs in transgenic plants leads to increased fungal resistance. The best-documented PGIP is PGIP2 from Phaseolus vulgaris , the common bean. PvPGIP2 has been successfully expressed in transgenic plants, resulting in increased resistance to fungal infections against Alternaria citri, Aspergillus flavus, A. niger, B. cinerea, Claviceps purpurea, and F. graminearum. Similarly, expression of PGIP3 from soybeans in tobacco has been shown to inhibit the growth of pathogenic Sclerotinia sclerotiorum, Fusarium moniliforme, B. aclada, A. niger, Collectotrichum acutatum, and F. graminearum; and expressing PGIP2 from lima beans in tobacco also delayed growth of Collectrichum lupini, B. cinerea, F. moniliforme, and A. niger.

Recently, it is also found that truncated PvPGIP2 with only the optimal docking area retains similar level of inhibitory activities towards PGs from A. niger and B. cinerea to the full-length PvPGIP2 . Yeast strains secreting full-length or truncated PvPGIP2 with the Ost 1 signal peptide were also able to reduce fungal growth and delay sporulation by 1–2 days . Although the function of PGIPs when applied exogenously on plants has not been reported, this group of proteins is still considered as a promising candidate to be developed into an eco-friendly fungal control agent. Albumins are a major class of water soluble, seed storage proteins that are used as a source of nutrients for plants during germination. Among them, 2S albumins have anti-fungal capabilities, in addition to a variety of activities including anti-cancer, anti-fungal, anti-bacterial, and serine-protease inhibiting properties . These small storage proteins are present in both monocotyledonous and dicotyledonous plant seeds and typically have a disulfide bridge linking two different subunits,container vertical farming which are typically between 3 kDA and 10 kDA in size. For example, pumpkin 2S albumin is thermal-stable at up to 90 ◦C, and exhibits inhibitory activity against the fungal pathogen F. oxysporum. Similarly, a crude extract of peanut containing 2S albumin was found to inhibit growth of A. flavus; the 2S albumin ortholog from passionfruit could also inhibit the fungal pathogens T. harizanum and F. oxysporum, C. musae, and C. lindemuthianum; and the 2S albumin ortholog from Putranjiva roxburghiicould inhibit the growth of F. oxysporum, Phanerochaete chrysosporium, C. albicans, Aspergillus fumigatus, and A. flavus. In addition, putrin is stable at up to 50 ◦C and within a pH range from 6 – 8. On the other hand, 2S albumin from white sesame seeds, oriental mustard, and Brazil nuts can bind to IgE sera, which may trigger an allergic response in humans. Thus, before 2S albumin can be utilized as an exogenously applied anti-fungal agent, we need to either engineer the protein to eliminate or reduce the allergenicity or modify the application in a manner that avoids either extensive contact or consumption. The fresh market berry industry in Santa Cruz and Monterey counties is an excellent example of transformation in the business of agriculture over the last 50 years. Located along the Central Coast of California, the two counties span the fertile Pajaro and Salinas valleys, and are well known for their amenable climate and production conditions, their diverse crop mix and grower demographics, and their developed agricultural infrastructure and support industries. The majority of the berry sector is comprised of strawberries , raspberries and blackberries , with blueberries and other miscellaneous berries produced on a much more limited basis. Substantial research-based literature and historical information is available for Central Coast strawberries; however, despite the area’s move towards greater production of raspberries and blackberries, less information exists for these crops.

We seek here to provide a more complete portrayal and historical context for the berry industry in the Santa Cruz and Monterey area, which is the origin of the berry industry in California. While the berry industry has been very successful in recent decades, it now faces new challenges, such as invasive pests and the phaseout of the soil fumigant methyl bromide. This article draws on previous and more recent research to discuss some of the influences that have contributed to the berry industry’s dramatic expansion in Santa Cruz and Monterey counties, including selected innovations in agricultural practices and heightened consumer demand. Berry industry growth During the 1960s and 1970s, the number of acres planted to berries, tons produced and value of production fluctuated. The fluctuations can be partly explained by farm management: in the past growers often rotated berry and vegetable crops to assist with soil and pest management, thereby influencing these statistics. However, annual crop reports from the county agricultural commissioners show that since the 1980s, berries have become increasingly important to each county’s overall value of production, and by 2014 accounted for 64% and 17% of the total value of all agricultural products in Santa Cruz and Monterey counties, respectively . The industry’s growth can be explained by a shift of some acreage out of tree fruits and field crops , among others, into berries, and by additional acreage put into agricultural production. Strawberries are the undisputed leader in the berry sector and in 2014 represented 58% and 94% of the value of all berry production in Santa Cruz and Monterey counties, respectively , and 50% and 93% of all berry acreage . Table 2 documents the remarkable expansion of the strawberry industry over time in both counties with respect to acreage, tons produced and value of production. Between 1960 and 2014, acreage more than tripled and production increased tenfold. The value of production, in real dollars, increased by 424% in Monterey County and by 593% in Santa Cruz County, reaching an astonishing combined value of nearly $1 billion in both 2010 and 2014. The gains in all statistical categories in Monterey County were enabled in part by an expansion of production into the southern reaches of the county where more and larger blocks of farmland are available, and where land rents are lower than in Santa Cruz and northern Monterey counties. However, from 2010 to 2014 Monterey County’s tonnage and production values declined, possibly because the area has recently experienced a shortage of labor to harvest fresh market crops. Tonnage was also lower in Santa Cruz County, but production values increased. This may be because of the county’s greater emphasis on local agriculture, organic production and direct market sales, which are often associated with higher crop values. For raspberries, the acreage, tons produced and value of production grew steadily and most strikingly in Santa Cruz County , where production conditions for caneberries are optimal. For example, caneberry fields in Santa Cruz County are situated in areas that have well-drained soils and are protected from damaging winds. Also, fields are planted to take advantage of the growth and yield gains associated with southern exposures. Moreover, field-to-cooler travel distances are shorter in Santa Cruz County, which is critical for safeguarding the quality and marketability of these highly perishable crops.

The lack of location-specific information for both model input and model constraints thus is the largest uncertainty in quantifying field-level carbon outcomes . For any technology used for carbon outcome quantification, there is a trade off between cost and accuracy . Although no clear criterion has been established so far to accept or reject a technology, for any quantification technology to be scalable, its per-acre operational cost must be meaningfully lower or significantly lower than the expected monetized carbon values from adopting climate-smart practices. In the current U.S. agriculture carbon market with a carbon price of roughly US $20/t CO2e, for example, this criterion, based on the DOE ARPA-E estimation , means costs should be significantly lower than $10/acre/year for soil carbon and $50/acre/year for N2O quantification for large-scale deployment, including installation, calibration, operation, and hardware lifetime and at the same time, the technology should be able to achieve less than 20% error at the field level . No single existing technology can meet both of these expectations. Instead, we propose that a more viable path for quantification of field-level carbon outcomes in agricultural soils is through an integration of sampling, sensing, and modeling, defined as the “System-of-Systems” solution. The “System-of-Systems” concept means that the complex problem of quantifying agroecosystem carbon outcomes cannot be solved by using a single sensor or a model alone, but only can be solved by effectively integrating various approaches . Such a “System-of-Systems” solution should simultaneously comprise the following features : scalable collection of ground truth data and cross-scale sensing of E, M, and C at the local field level; advanced modeling with necessary processes to support the quantification of carbon outcomes; systematic Model-Data Fusion , i.e. robust and efficient methods to integrate sensing data and models at each local farmland level; high computation efficiency and AI to scale to millions of individual fields with low cost; robust and multi-tier validation systems and infrastructures to test model/solution’s scalability, defined as the ability of a solution to perform robustly with accepted accuracy on all targeted fields.

Thus the “System-of-Systems” solution is a holistic framework including multiple sub-systems for sensing, monitoring, modeling, and model-data fusion,hydroponi bucket targeting to assure field-level accuracy, scalability, and cost-effectiveness. The “System-of-Systems” approach is so far the only pathway to implement the mass-balance approach to quantify SOC changes, which requires various localized observations and the integration of observations/data with models to accurately estimate each term in the massbalance equation and achieve the field-level accuracy. Compared with existing approaches , there are several advantages of using the mass-balance approach to quantify the change of SOC. First, all of the carbon budget terms are measurable, although some being costly, and can be used to verify model accuracy and provide a basis for confidence. Second, all the carbon budget terms can be measured and verified at relatively short time scales, i.e. from sub-hourly scale to annual time scale , which enables the quantification of annual change of SOC. In contrast, soil sampling is generally not able to detect annual changes, as the uncertainty of soil sampling is usually much larger than the annual change of SOC. Third, those carbon budget terms for calculating the carbon input to soil can be estimated using advanced remote sensing technologies , which offers an efficient and scalable way to achieve the field-level observational constraints in a large region due to the ubiquitous coverage of remote sensing technologies. Fourth, the carbon mass balance approach provides a holistic picture of the overall carbon budget of farmland soils, which enables a mechanistic understanding of differential impacts of management practices on SOC from field to field and from year to year, thereby could help farmers to improve their management practices along with the changing climate. Scalably sensing/estimating local information of E, M, and C at the field level is the first step of a “System-of-Systems” solution, which involves two seemingly different but inherently connected tasks: ground truth collection, and cross-scale sensing. Ground truth here is broadly defined as information that is collected on the ground to train, constrain or validate models. Agricultural ground truth is scarce and expensive to collect.

For example, collecting carbon flux data requires eddy-covariance flux towers, which are generally costly to set up and operate. However, we also have to face the reality that even with low-cost sensing technology or crowd sourcing efforts, one cannot collect ground truth for every field. Instead, we propose to develop “cross-scale sensing” approaches, especially those enabled by remote sensing, to scale-up “ground truth” collection to large scales. Cross-scale sensing can be demonstrated by the most recent development of deriving field-level photosynthesis information. Photosynthesis is the only term for land carbon input and also the largest carbon budget term . Ecosystem photosynthesis is the primary driver for crop litter and thus significantly contributes to the long-term change in SOC, as demonstrated in Section 2.3. Correctly quantifying photosynthesis at the field level puts significant constraint and reduces uncertainty on simulated crop carbon dynamics, crop litter and soil carbon dynamics . A recent breakthrough in the remote sensing of photosynthesis was made possible by full integration of leaf level chamber/sensor measurements, canopy-level hyperspectral sensing , and regional-scale mapping through satellite fusion data . The cross-scale sensing here is guided by the domain knowledge of plant physiology, radiative transfer modeling, and hyperspectral theories; ground truth data – in particular, leaf-level samples and eddy-covariance flux tower data – are extensively used in the model development stage, but once the translation from ground-truth data to satellite-scale signals can be robustly developed, satellite fusion data can expand the photosynthesis information for every single field every day since 2000 to present . Another advance in cross-scale sensing is the use of intermediate sensing to augment traditional ground truth collection, and enable the scaling from leaf-level or plot-level ground measurements to coarse satellite pixel size – a classic problem in the area of remote sensing. A typical example is the use of airborne hyperspectral imaging . Hyperspectral imaging can provide estimates of certain soil and plant traits with high accuracy , although its application for scalable mapping has been limited by its high cost.

A novel use of AHI is to treat AHI data as an intermediate bridge between ground truth collection and satellite scale-up. A general procedure is to first develop robust methods to translate AHI signals with targeted estimates based on data from intensive lab and field experiments; and then to use AHI as a strategic sampler to selectively “sample” over space and time, serving as a bridge from granular resolution of ground truth to large satellite pixels; and finally, to use satellite data overlaid with the AHI sampled area to translate satellite multi-spectral signals along with environmental variables into plant and soil trait estimation, thus deriving targeted E, M, C variables ubiquitously using satellite data. Though similar approaches have achieved success in mapping forests canopy bio-geochemistry , they have rarely been used in agroecosystems. Once advanced and automated pipelines are established to conduct AHI collection and data processing , AHI can be applied to estimate crop canopy nitrogen content, cover crop biomass, and crop residue fraction and tillage practices. Fig. 7 demonstrates how AHI is used to scale up the estimation of crop residue fraction and tillage intensity at the regional scale. Other sensing approaches, such as mobile vehicle sensing , IoT sensing network and robotics , could also achieve a similar function to augment ground truth collection and enable satellite scaling-up to regional scales. Table 1 provides a non-inclusive list of different critical E, M, C variables that currently have been estimated using cross-scale sensing technologies. Have sufficient and necessary processes represented. Coupled carbon-nutrient-water-energy cycling over farmland is the foundation for field-level carbon outcome quantification,stackable planters thus models should include a sufficient number of mechanistic pathways that clearly track the input, output and storage of water, carbon, nutrient and energy in crop lands under the interference of agricultural management. For the plant component, simulating the responses of crop carbon uptake and water use to different abiotic and biotic stresses is necessary as they largely determine the crop production and carbon input to the soil. From this perspective, proper representation of canopy energy balance, stomatal conductance, uptake and transport of water and nutrients from soil to canopy are needed to mechanistically simulate the crop carbon and nutrient uptake and crop water use . Many of the existing process-based models may lack critical processes or use over-simplified processes to model specific carbon outcomes. One obvious example, following our prior discussion on the importance of the holistic carbon budget of agroecosystems, is that most existing process-based models lack sufficient mechanisms that can model plant carbon processes as emergent phenomenon , resulting in significant errors when quantifying the downstream ΔSOC. For example, lack of explicit modeling of photosynthesis , plant stomatal responses to environmental stresses , and reproductive processes for yield can cause huge uncertainty of the modeled carbon input to the soil pools, contributing significant error to the simulated ΔSOC. For the below ground part, soil temperature, water, oxygen, and pH dynamics, bio-geochemical reactions related to carbon, nitrogen and phosphorus cycling, microbial activities and their regulation on SOM formation and stabilization as well as GHG emissions are core processes that need to be simulated. For example, recent studies identified two distinct pathways of SOM stabilization from litter decomposition, i.e. the DOM-microbial pathway in the early stage of decomposition, and the physical transfer pathway in the final stage of decomposition .

This work emphasized the importance of dissolved organic matter and microbial activities, and necromass in stabilizing SOM . Having those mechanisms and their interactions with related environmental drivers well represented in the soil carbon models is essential to accurately simulate the dynamics of SOC and its physical fractionations. Besides these biophysical and bio-geochemical processes, representing the farming management practices and their impacts on coupled carbon nutrient-water-energy cycling over farmland is critically needed to quantify the carbon outcomes. Neverthless, there should be a good balance between model complexity and practicality. Any model used for operational carbon outcomes quantification should have necessary complexity and processes, and new theoretical advances in science should be ultimately incorporated into existing models to improve representations of relevant processes. However, we also need to acknowledge that models with new mechanistic representations are not always better than simpler models in practice, especially when there is not enough data to constrain those new mechanistic representations. When evaluating the appropriate model structures for agricultural carbon outcomes, we should focus on two fundamental questions: Is a specific process indispensable for simulating the specific outcome and also achieving the desired accuracy? Is there sufficient data to parameterize that specific process at both field and regional scales? If the answer to either question is no, then including the new process may not necessarily benefit the quantification of carbon outcome for now. Maximum use of mechanistic process representation. To simulate biogeochemical and biogeophysical processes, many existing models use multiplication factors , law of the minimum , and empirically-derived response functions , all of which are ad hoc by nature. One consequence of these non-mechanistic modeling approaches is that different researchers applying the same method to a given process will obtain different mathematical representations, which then lead to a loose foundation to implement that particular process in these models . Moreover, non-mechanistic representation which lacks support from physical laws also limits the generality and scalability of the model simulations, especially when a model is used to extrapolate beyond the environmental and management conditions under which the model is previously developed or calibrated. For example, many models use the empirically-derived soil water stress functions to depict the down-regulation of crop carbon uptake and water use under water stress conditions, which causes inconsistencies and discrepancies in multi-model intercomparison simulations . A more mechanistic way to account for crop soil water stress would be to explicitly represent the plant-hydraulic-stomatal-photosynthetic coordination from soils to plant, and to atmosphere . Similarly, most models formulate soil carbon decomposition rate by assuming different controlling factors independently and multiplicatively scale the decomposition rate ; in reality, these factors are interacting and intertwined following specific mechanistic pathways to lead to decomposition rate, but very few existing models include such interactions and mechanistic pathways . Another example is how the impacts of different tillage practices are represented on soil physical and biogeochemical processes.

In the northern Peloponnese, currants were grown in Patras, in Vostizza , and in the village of Sikionas, just West of Corinth. Currants also spread to the southern coast of Aetolia in towns along the gulf, including Lepanto , Anatolikon , and Messolonghi. From these locations, currants were shipped to the port of Patras, which became the bulking center for currants grown in Ottoman territory before their journey westward.Despite the continuing cultivation of currants in Ottoman Greece in the sixteenth and seventeenth centuries, most currants were grown on the Venetian Ionian Islands during this time. The English traveler to the Ionian Islands Sir George Wheler wrote in the late seventeenth century that Zakynthos produced enough currants annually to fill five or six cargoes, and Kephalonia produced enough to fill three or four. At the same time, all the currant-growing regions around the Gulf of Corinth in Ottoman Greece—Anatolikon, Messolonghi, Patras, and Lepanto—together only produced enough to fill a single cargo.This continued throughout the eighteenth century and well into the nineteenth century, even as currant cultivation abated substantially on Zakynthos and Kephalonia and intensified somewhat in Ottoman Greece. In the eighteenth century, currants circulated through the early modern trade networks that connected the major trading hubs of the Mediterranean, including Venice, Trieste, Livorno, Smyrna, and Constantinople. The primary market was England, but they were also destined for consumption in Holland and elsewhere in Europe. By the end of the eighteenth century, there were six million Venetian liters of currants being exported from the Peloponnese, mainly from Patras.On the eve of the Greek Revolution, currant cultivation was growing, but currants remained the product of isolated zones of specialization around the Gulf of Corinth and on the Ionian Islands. The currant-growing places were not yet united into a region—they remained small islands surrounded by a sea of diverse cultivation. First, the demand for currants in Britain,livestock fodder system the main currant-importing country, increased due to changing consumption habits.

This was just the latest development in a longer process. In the eighteenth century in Britain, the growing middling and trading classes had adopted new consumption habits. Demand for luxury items was previously limited to the old elite, but with the expansion of British trade and growing prosperity, there was an increase in demand for luxury items and non-essential food commodities from faraway places such as tea and sugar and the porcelain and silver with which to consume them.The Industrial Revolution in Britain in the late eighteenth and early nineteenth centuries expanded this consumer class even more and increased demand for these commodities. Rituals were created to consume these commodities. For example, breakfast and tea-drinking were both new rituals that were introduced in Britain in the eighteenth century. These customs coincided with the introduction of hot beverages such as coffee, chocolate, and tea and the ceramic, silver, and steel commodities used to consume them. By the middle of the eighteenth century, it was customary among middling and trading groups to consume a breakfast of bread and tea.One of the commodities that experienced a rise in demand was puddings, or sweet desserts made with sugar and dried fruit—particularly Greek currants. As described above, the market for currants in England to be consumed in puddings goes back to the fourteenth century or earlier, but because of new consumption patterns, around the middle of the nineteenth century, this market began to grow at a much faster rate. By the middle of the century, currants were the main export of the Peloponnese and of all of the Kingdom of Greece, and the UK was their principle market.The second half of the nineteenth century marks the period that Nikos Bakounakis calls the “age of pudding” in Victorian Britain.38 Pudding consumption rose in Britain among the lower and middling classes, and dried fruits were an essential ingredient in these puddings.The publication of Charles Dickens’s A Christmas Carol in 1843 popularized the holiday ritual of serving Christmas pudding made with dried fruit and adorned with a sprig of holly. Christmas pudding became a mainstay of the season, and other puddings became popular as year-round favorites.

The recipe for spotted dick, for example, which seems to date to an 1849 cookbook marketed to middle-class British housewives, calls for “Smyrna raisins” or sultanas to create the “spots.”Puddings became a sign of abundance and of the happiness of the bourgeois family— Greek currants became an essential ingredient in the aspirations of the upwardly mobile British population. Pudding consumption rose in Britain among the lower and middle classes, and Greek currants benefitted from this general trend. During the period from 1846 to 1876, the consumption of sugar and currants rose dramatically. Annual sugar consumption in England was 14 lbs. per person in 1846, but it grew to 60 lbs. in 1876. Currant consumption rose to a similar degree: total currant consumption in England was 14,000 tons in 1844, and it rose to 46,000 tons in 1874. Moreover, as the demand for dried fruit increased, currants also captured a greater relative share of this market. Currants displaced other types of raisins in London and Liverpool. In the years 1831 to 1840, 48% of the raisins consumed in these cities were currants. This number grew to 66% from 1860 to 1869.In the 1870s, 55% to 75% of Greek currants were being exported to Britain to meet this growing demand.As a French traveler to Greece wrote in the middle of the nineteenth century, “If Greece were to cease to produce these precious little black grains, there would be no more plum-puddings, nor plum-cakes, nor any of those dainties of which plums or currants are the foundation…. England would have been deprived of the purest of her pleasures, and Greece of the most certain of her revenues.”44 The demand from Britain was also promoted by greater access to the currant trade in the Peloponnese in the nineteenth century. During this time, Patras rose in importance to become the main port of the Peloponnese and one of the three main ports in the Kingdom of Greece alongside Piraeus and Hermoupolis. In the eighteenth century, Patras was an important regional port that served as a “bulking” or collecting center for the Gulf of Corinth and Elis. Smaller ports such as Vostizza and Lepanto sent their cargoes to Patras to be collected before being sent on to European ports to the West.

The other major ports on the Peloponnese—Navarino, Methoni, Coroni, and Nafplion—shared the rest of the peninsula’s trade. The French Revolution was a turning point for Patras, when the French lost their control over trade in the eastern Mediterranean. For the duration of the French Revolutionary period , Greek merchants dominated trade in the eastern Mediterranean more than any other group. As a result, the French ports such as Coroni declined. Moreover, with the implementation of the Continental System, the British turned to the Eastern Mediterranean for sources of commodities and for markets for their manufactured goods. Consequently, Patras enjoyed a greater relative share of the peninsula’s trade and increasing trade with Britain. During the French Revolutionary period,Patras handled 30% of all Peloponnesian exports to Western Europe, and the rest was divided among the peninsula’s other ports.46 After the Napoleonic Wars, the English displaced the French in the Eastern Mediterranean. The Italian ports declined, but Patras continued to grow through closer connection to British ports in the Ionian Islands and Malta. From 1815 to 1820, Patras’s relative share of the peninsula’s trade with the West suddenly doubled from 30% to 60%. Due to the disruptions caused by the French Revolution, Patras emerged as the dominant Peloponnesian port for trade with Western Europe and the eastern Mediterranean.During the Greek War of Independence, Patras was completely destroyed, the population left, and the land was not cultivated. The war was a violent break with the past, but Patras and its vineyards were able to recover quickly. The destruction left Patras as a tabula rasa. Under the influence of British demand for currants,hydroponic nft gully the city was remade into a port-city with its orientation shifted to the sea. Before the war, the center of  Patras was perched on a hillside, and the city was oriented inward toward its hinterland. After the war was over, the old town on the hillside was rebuilt, but a new city was also built on the coast beside the old city on land that was previously occupied by vineyards .The engineer Stamati Voulgaris who planned the reconstruction of the city moved the demographic and economic center of the city from the hills to the sea and made plans for a new port. Patras after the Greek Revolution was therefore a new city with a “double” landscape: the sea and the plains on the one hand, and the hills on the other.The newly rebuilt Patras sent most of its exports to Britain and its territories in the eastern Mediterranean. Patras continued to ship to the Italian ports, but the percentage of total exports from Patras that were bound for London, the Ionian Islands, and Malta reached 73%.Patras also began receiving imports directly from European ports. Before the revolution, Patras received European commodities after they had stopped first in a larger Ottoman port such as Smyrna.

As a part of the newly independent Kingdom of Greece, Patras received cargoes of textiles sent from British ports in the Ionian Islands and Malta. Patras also imported other manufactured goods and food commodities such as sugar, coffee, and pepper.51 By the 1830s, therefore, the currant trade and Greek trade with Britain were both concentrated in the port of Patras. The technological innovations of the Second Industrial Revolution lowered the speed and costs of transit, promoting the continuing integration of Greek agricultural production with Western markets. Most significantly, improved steam ship transport in the second half of the nineteenth century meant that Patras no longer needed to trade with Britain through the ports in its Mediterranean colonies but could trade directly with British ports. By the middle of the century, merchants had opened steam ship lines to carry currants directly from Patras to London, Liverpool, Falmouth, Newcastle, and Southampton, and Patras also began importing directly from British ports. Patras continued to trade with Malta and the Ionian Islands, but now there was a direct connection as well.Steam ship transport also deepened the currant growing region’s connections to North America. The United States had begun importing Greek currants as early as 1835 due to the efforts of the Chian merchants Andreas and Pantellis Phakiris and their merchant house based in Patras.London had a near monopoly on shipping currants to the US and Canada at first, but by the end of the nineteenth century, steam ships were leaving Patras bound directly for North American ports.54 In fact, currants were the sole reason for trade between Greece and the US. Until the very end of the nineteenth century, currants made up 90– 100% of Greek exports to the US.A technical innovation in the practice of currant cultivation in the Peloponnese may have also played a role in the spread of currant cultivation further to the west and the south in the second half of the nineteenth century. This was a technique called “girdling” or “ring-cutting” . Ring-cutting involved removing a thin strip of bark in a ring around the base of the vine, about 2–3 cm. wide. Ring-cutting was done in mid-May at the appearance of the first growth on the currant vines. Ring-cutting was strenuous work performed by skilled laborers called harakotes. If done right, ring-cutting caused the fruit to grow larger, but there was plenty of room for error, and the stakes were high. If the faltseta, or pruning knife, cut too deep, the vine would die, but if it did not cut deep enough, the cut would be ineffective. The harakotis also had to determine the appropriate width of the cut based on the quality of the soil and the age and strength of the vine. Weaker vines and less fertile soil required a narrower cut, and hardier vines and more fertile soil required a wider cut. Moreover, the task had to be completed within ten days, “as otherwise the ripening of grapes would not be uniform and problems would arise at harvest-time.”Because it was physically taxing, time consuming, and required special skill, ring-cutting was highly paid work.Ring-cutting was introduced in the Peloponnese in 1848 when the technique was first applied by workers who came to the peninsula from Zakynthos.

The old rules of land use had changed to the benefit of some and the detriment of others. Less affluent Greek villagers were forced to assume a greater risk of subsistence failure so that wealthier Greeks might profit, and many people were compelled to resist such changes. Suddenly, in the early 1890s, foreign demand for Mediterranean agricultural products evaporated, and the gains of export agriculture in Greece were swiftly reversed. The ensuing economic crisis sent the Greek government into bankruptcy. Free-standing companies formed to undertake land reclamation projects were also bankrupted, and their backers in Paris, London, Athens, and elsewhere saw their investments disappear. Small farmers in the Peloponnese who had gone into debt to plant their plots with currant vineyards could no longer sell their produce, and they could not command the resources needed for their own families’ subsistence. Indebted, impoverished, and unable to find work, many of them abandoned their land, often emigrating in search of new opportunities. At the close of the nineteenth century, after much effort and at great expense, the landscape, agricultural system, and settlement patterns of rural Greece had been reformed to better satisfy foreign demand for Mediterranean agricultural commodities—a demand that no longer existed. The consequences of this period were felt in Greece for decades. This dissertation comprises two parts,stacking pots each built around a regional case study of foreign demand for Greek agricultural products creating homogenous zones of monocultural specialization out of diverse and fragmented landscapes. Part one focuses on the first case study region: the coastal, currant-growing areas of southern Greece.

Over the course of the nineteenth century, growing foreign demand for Greek currants made them into a global commodity. Because of this, in the parts of Greece that could grow currants, agricultural practice shifted from diversified agriculture and transhumant pastoralism to the much risker pattern of permanent lowland settlement and year-round currant monoculture. The currant-growing region expanded as currant vineyards extended from traditional zones of specialization to encompass the north and west coasts of the Peloponnese, the south coast of Aetolia-Acarnania, and the Ionian islands of Zakinthos, Kefalonia, and Ithaki, with the attendant alterations made to the Greek landscape in these places. Chapter three describes how and why Greek currants became such a highly demanded global commodity in the second half of the nineteenth century. Chapter four examines the consequent transformation in the Peloponnesian Greeks’ relationship with their environment as currant vineyards extended throughout the region and seasonal migration gave way to permanent lowland settlement. The physical landscape was also transformed as lowland wetlands were drained and hills were terraced to make the region better suited to intensive, specialized currant viticulture. The second part of this dissertation centers on the second case study region, Boeotia, in Central Greece. At the time that currants were taking off in the Peloponnese, different Greek products became profitable commodities in other parts of the country. In Boeotia, the most important crops were cotton and grains. Chapter five examines how demand for these Greek products created the imperative to drain a large lake in Boeotia and turn it into an irrigated estate for the intensive cultivation of cash crops. First, it describes the larger context within which these Greek goods became global commodities. Then, it describes the project to drain this lake to produce arable land for agriculture. Finally, chapter six describes how, after the physical landscape of Kopaïda had been transformed to suit these new imperatives, the region still had to be transformed socially and politically.

I conclude by examining the effects this period had on the long-term trajectory of development in Greece. The path of progress in rural Greece was neither straight nor smooth. As a result of landscape abandonment, rural depopulation, and the elimination of resources, the Greek rural economy remained impaired well into the twentieth century. Linear narratives of development in the Mediterranean have neglected the ways that the countryside of Greece was at its productive apex in the late nineteenth century, and they have also neglected the ways this early period of economic modernization stymied growth in the first half of the twentieth century. Before exploring these case study regions, the next chapter situates the present study within the historical literature on Modern Greece and the Mediterranean and elaborates on the methodological considerations underpinning this dissertation. Research in several disciplines has uncovered the effects of the incorporation of Mediterranean agricultural production into a global, capitalist system in the eighteenth and nineteenth centuries. The preponderance of research on this topic has come from an economic perspective. Economists and economic historians have demonstrated the ways development in Greece and the greater Mediterranean region during this time was tied to export agriculture, and they have also demonstrated the ways the globalization of Mediterranean agricultural production caused these countries to develop in a subordinate or “peripheral” position.1 Social and economic historical scholarship has also focused on the wide-ranging effects of the nineteenth century boom in Mediterranean commercial agriculture on the political organization of this region and the formation of classes and cultural identities.2 Despite compelling research on the long-term social and economic consequences of this period, the environmental transformations made in Mediterranean Europe in the nineteenth century to sustain intensive commercial agriculture are not well understood. The effects of global capitalism on the landscape and environment of the Mediterranean have been widely noted, but this area of inquiry has received less scholarly focus.

Recent scholarship on the Anthropocene and the so-called Capitalocene has brought these questions to the forefront. The spread of global capitalism in the nineteenth and twentieth centuries had significant and often permanent environmental effects in developing countries worldwide, including air and water pollution, deforestation, resource depletion, severe erosion, and an overall decline in biodiversity due to the destruction of ecosystems. With respect to the Mediterranean in general and Greece in particular, many questions remain about the environmental changes brought by global capitalism, including the regional variations exhibited, the mechanisms of landscape transformation, and the long-term social and economy consequences. Despite this gap, there is a great potential for such an environmental history of Modern Greece building on more well-developed fields. In this chapter, I situate the present study within the existing scholarship on the social and economic history of the Eastern Mediterranean in the nineteenth century, agriculture and historical ecology in the Mediterranean, and the global environmental history of capitalism. First, I review the literature on the incorporation of the Mediterranean into the emerging global, capitalist economy in the eighteenth and nineteenth centuries— this was the catalyst for the social and environmental transformations examined in the chapters that follow. In the second section, I argue that the scholarship on the historical ecology of the Mediterranean and “traditional” Mediterranean agriculture can help to contextualize the environmental changes seen in Greece in the nineteenth century. Finally, I situate this study within European, Mediterranean, and global environmental history. Here, I place the historical, anthropological,strawberry gutter system andarchaeological studies that have been done on Greece into a broader context and put them into conversation with the environmental historical literature on Italy, Egypt, Germany, and other places where the sub-field has enjoyed greater success. Over the course of the eighteenth and nineteenth centuries, labor and commodity markets in Southeastern Europe and the Eastern Mediterranean were more thoroughly integrated into a global economic system. The terminology commonly used to describe this process comes from World Systems Analysis. Immanuel Wallerstein developed the World Systems model to explain how capitalism functions on a global scale and how, because of market integration, some regions became rich and powerful while others seemed stuck in a trap of relative under-development. In Wallerstein’s model, the modern world-system—i.e. the capitalist world-economy—emerged in Northwestern Europe in the fifteenth century and slowly expanded by incorporating new labor and commodity markets. The expansion of the world economy divided the globe into three distinct zones that Wallerstein, borrowing from Dependency Theory and Andre Gunder Frank, termed the core, the periphery, and the semi-periphery. These categories reflect the distribution of wealth and functions within the system. The core regions imported raw materials from the periphery, manufactured them into finished products if necessary, and exported the surplus back to the peripheral territories for purchase and consumption. The core, therefore, possessed capital and the means of production, and the periphery supplied cheap, labor-intensive commodities.3Before this system emerged, the predominant world-system was the world empire. Unlike the modern world-system, which was singular, many world empires could coexist at once. Each world empire unified a single division of labor under a single state structure. Their economic integration was limited to the exchange of luxury goods. Strong world empires were capable of controlling production within their own domains, channeling revenue from production toward the center through taxation and controlling the distribution of wealth to keep the ruling class dominant. Weak world empires, meanwhile, were dismantled and incorporated into rival world empires. In contrast, the modern world-system unified a single division of labor within multiple state structures, and economic integration of states in this world-system went well beyond the exchange of luxury goods. The division of labor was no longer directed toward the maintenance of elite power within the state structure, as in a world empire. Instead, it followed a capitalist rationality and was directed toward the endless accumulation of capital in the world center.

World Systems Analysis has been one of the dominant paradigms for studying market integration in Southeastern Europe and the Eastern Mediterranean in the modern era. Inspired by this model, scholars since the 1970s have studied the incorporation of the Ottoman Empire and the Balkans into the European economy in the eighteenth and nineteenth centuries. Using Wallerstein’s vocabulary, they initially termed this process “peripheralization.” Trade took place in a few major Eastern Mediterranean port-cities—Salonika, Smyrna, Patras, Beirut, and others—and these cities’ Jewish, Greek, Maronite, and Armenian populations acted as intermediaries between Ottoman commodity-producers and European merchants.5 These minority merchants began shipping Ottoman agricultural products, including staples, to Europe. Through this process of commodification, the Porte lost its power to control agricultural production within the empire, and as a result, agricultural production shifted to meet European market demands. In the Balkans, large estates called çiftliks were amalgamated to produce agricultural products to be exchanged with Europe.6 As the Ottomans ceased to be able to control the agricultural production within their own realms, the empire ceased to be a self-contained world-empire, and the agricultural production within the empire ceased to be an engine of the reproduction of imperial authority. Through tax farming and the rise of contraband trade with Europe, Ottoman agriculture became commercial, and the Ottoman labor market was integrated into the world labor market.7 In addition to studying the process by which regions were incorporated into the European economy as a periphery, scholars have also been interested in the social and political consequences of peripheralization, particularly through the formation of national and class identities. For example, the disintegration of the Ottoman Empire into nation-states in the nineteenth and twentieth centuries is understood as an effect of market integration. The economic and intellectual ties ethnic minority merchants in the Ottoman Empire developed with the West facilitated the political transformation of the region. The creation of a cosmopolitan bourgeoisie and their conversations with the West helped to unravel the Ottoman Empire and reorganize the region politically into nation-states.As such, these cities are also considered sites of class formation. European economic penetration created commercial bourgeoisies that benefited from European capital as well as working class populations that resisted it, forming their class identities through labor organization and strikes.The world-systems model has been criticized for its adoption of a Eurocentric narrative that maintains that there was a single, modern European world-system into which the rest of the world was incorporated, overlooking the systems and networks that existed in these places before the moment of their incorporation.When applied to the Mediterranean, the model’s focus on “high commerce” may be said to “minimalize” the pre-modern economy—by neglecting the regional connectivity that existed well before the eighteenth century, the model does not take into account the dense trade in staples as well as luxury goods that occurred through the movement of small cargoes and was present since antiquity.Others have argued that World Systems Theory exaggerates the role of international influences as an explanation for Balkan economic under-development, and that Balkan “dependency” on Europe is too steep a claim.

Many studies illustrate that intensification can be unsustainable, but several notable projects in Africa and elsewhere have shown that sustainable intensification is possible and necessary to boost global crop production. Clearly, the world faces a looming and growing agricultural crisis. Yields are not improving fast enough to keep up with projected demands in 2050. However, opportunities do exist to increase production through more efficient use of current arable lands and increasing yield growth rates by spreading best management practices and closing yield gaps under different management regimes across the globe. A portion of the production shortfall could also be met by expanding croplands, but at a high environmental cost to biodiversity and carbon emissions. Alternatively, additional strategies, particularly changing to more plant-based diets and reducing food waste can reduce the large expected demand growth in food.We used annual crop census reports for harvested areas and yield from ,13,500 political units globally covering 20 years from 1989 to 2008 in this analysis though the database itself covers the years 1961 to 2008. The sum total of these census reports for the 20 years was approximately 1.8 million.Data were not available for all political units for each year. Details of the number of years data was available and its source is given in the Table S1. For the political units where data was missing for some years we estimated crop harvested and yield information using the average of the latest five years of reported data and constraining them with the reported numbers from the higher political unit as explained further in Text S1 and previous work. Population data and its projections per country were from the United Nation’s medium variant projections. Crop production was determined using the projected crop yields at current observed rates of yield change and harvested areas fixed at ,2007. Per capita harvested production is the ratio of production to population and a greater than 610% change from ,2007 is considered as significant either in the short- or long-term .While the relationship between the commercial agriculture sector and the Venezuelan state is often oppositional and conflictive,hydroponic nft this chapter argues that sectors of commercial agriculture also benefit from government policies.

This policy capture allows commercial farms to reproduce themselves and largely maintain their socio-economic position. Reading commercial agriculture and state relationships as conflictive, therefore, is incomplete and leaves relatively unpacked an important sector of Venezuela’s overall agro-food system. Specific relationships between the state and the commercial sector and the implications for reform of the smallholder sector are largely absent from contemporary analyses of the Venezuelan agrarian reform process that tend to focus almost exclusively on statepeasant relationships. This chapter addresses this analytical gap by considering relationships between the state, commercial agriculture, and the peasant sector. A more relational look between commercial agriculture and the Venezuelan state can also help problematize literature that characterizes the Chavista state as socialist in intention, if imperfect and incomplete in its implementation. The dynamics of commercial agriculture in the agro-food system reveals how agricultural policy in Venezuela’s petro-socialist context actively maintains commercial growers, the often-discursive ‘enemies’ of the agrarian reform. The state’s emphasis on raising production to maintain food availability in the face of scarcity and to reduce dependence of food imports, shapes policy in ways that help to reinforce the position of commercial agriculture, even as its stated policy emphasis is promotion of the smallholder sector and a reordering of agrarian social relations. The alignment of the major agribusiness federation FEDEAGRO—as well as FEDENAGA the cattle ranchers’ association—with the political opposition to the government, a number of high-profile fights over state land seizures, nationalizations of supermarket and agricultural input firms, and violence against peasants active in the agrarian reform process would seem to paint an overwhelmingly contentious picture of relations between commercial agriculture interests and the Venezuelan state. Indeed, landowners and commercial elites have stymied reform efforts through legal challenges, by wielding influence in local networks or regional institutions involved in agrarian reform, and by using violence against peasants involved in the agrarian reform process.

The land reform’s perceived attack on private property rights and the supposed failures of government intervention in the food system figure prominently in opposition critiques of the state. These oppositional aspects of the commercial sector vis á vis the state have often been portrayed in the literature on Venezuela as indicative of class conflict in a period of socialist transformation and representative of barriers to implementation of state policy . For example, Enríquez argues that roadblocks to reform in Venezuela’s land reform sector are in large part due to the functioning of ‘dual power’ in Venezuela, where Venezuela’s landed elite struggle to maintain their class position in a reform process that seeks to wrest control of the agricultural system and remake it privilege other actors and production systems. Enríquez argues the ‘old regime’ has been able to fight reform in the context of ‘brown areas’ , geographical, economic, political, or ideological spaces where old systems remain outside the control of the reformist state. These brown areas afford agricultural elites possibilities to block implementation of reforms that challenges their interests. In this reading, the Chavista government has been unable to completely capture state institutions in order to remake them to function for new, ‘socialist’ goals, or state institutions have failed to break landowner influence in specific areas of Venezuela. Harnecker’s analysis of the ‘revolutionary’ states of Venezuela, Bolivia and Ecuador argues that an old state and an emerging, more progressive state coexist in a ‘relationship of complementarity’ during a transition to socialism . Harnecker argues that the ‘bureaucraticism’ of the old state can impede progress towards development of the socialist state via persistent ‘excessive centralization’ . If we apply Harnecker’s frame to the agrarian reform, the continued hold on prime agricultural land by commercial producers in Venezuela is explained primarily by reform policies being bogged down in the bureaucratic morass of state institutions charged with their implementation. In this reading, Venezuela is characterized as a state transitioning to socialism whose revolutionary goals are being blocked by barriers emerging from this amalgamation of an ‘old’ and ‘new’ state.

This dissertation, however, argues that a simple oppositional/class conflict role in agrarian relations between the landed class and state and agrarian reform sectors, and the related assumption that a socialist economy is the primary goal of state policy-making, is incomplete. Harnecker’s vision of an old versus new state can leave unexamined relations between the state and the capitalist sector that can inform how reformist/revolutionary states engage with this sector in strategies that balance economic and political needs. Enríquez’s argument that incomplete control over institutions and territories by socialist actors impedes the transformation of rural social relations does not address the state’s relationships with the commercial agriculture sector nor the broader political economy dynamics of a petro-state and how they shape both policy formation and implementation. By engaging with structural and policy dynamics between the capitalist commercial agriculture sector and the state, this chapter seeks to firstly, bring in the capitalist sector into an analysis of state agro-food policy in order to understand Venezuela’s greater agrarian political economy, while avoiding overly facile characterizations of relationships between the state, commercial agriculture, and the peasant sector as necessarily conflictive. Secondly, this chapter links this broader agro-food policy analysis to political economic dynamics of Venezuela as a petro-state. This is not to argue that class conflict between agrarian elites and the state is not central to agrarian dynamics. Class conflict does indeed permeate the agrarian reform. Rather I argue that understanding commercial agriculture’s relationship to the state from a more critical perspective illuminates constraints on policy formation and implementation in Venezuela as a reformist state pursuing a mixed-economy model in an extractive industry context. This chapter draws on the state of Portuguesa as a case study to illustrate the dynamics of commercial agriculture and Chavista agro-food policy. Portuguesa is one of the most important agricultural centers within Venezuela,hydroponic channel especially in cereal and oilseed production and related agro-industry. In 2001, Portuguesa produced over half of the country’s rice and 90% of its sesame . Indicative of its influence in agriculture circles, the president of FEDEAGRO is a grower from Portuguesa, who also heads ASOPORTUGUESA, an important local grower association. This chapter is arranged in three parts. Part one examines the historical formation of agrarian relations in Portuguesa and charts the state’s development of a vertically-integrated agro-industrial sector. Part two analyzes contemporary agricultural policy and relationships between the state and commercial agriculture within Portuguesa.

Part three places these agrarian dynamics within the broader political economy of Venezuela as a petro-socialist state and its orientation towards a mixed economy in its agriculture sector. Portuguesa, especially the agro-industrial center of Acarigua-Araure, is at the core of Venezuela’s breadbasket. Prior to the 1940s, however, the area around Acarigua was a thinly populated area of tropical forest mixed with savanna whose economy was based primarily in exploitation of forests for lumber, cattle ranching, and whose peasantry grew some staple crops as well as serving as occasional labor in sawmills . Portuguesa was, thus, not central to the agrarian economy in the pre-oil era that was based on plantation production of coffee and cacao for export. The transformation into Venezuela’s premier agro-industrial area grew out of centralized state development programs that restructured agrarian relations and land ownership patterns, mobilized state capital for the development of mechanized and largely capital intensive agriculture, and subordinated the 1960s agrarian reform program to serving the labor and raw material needs of the emerging commercial growers . The eventual result was the formation of a vertically integrated, commercial agrarian elite that dominated the socio-economic life of the region. By the 1940s, rising GDP from the expansion of oil production and rapid urbanization in Venezuela created a growing demand for agricultural products that outstripped domestic production capacity. In response, policymakers sought to modernize the agricultural sector to raise production to meet national food needs. Efforts to modernize the agriculture sector by the military governments ruling Venezuela in the 1940s and 50s saw the Portuguesa economy transform into a principal crop producer in the nation. The Venezuelan state was instrumental in the establishment of a production system oriented towards larger-scale mechanization of commodity crops that displaced the previous agricultural systems. Managed by the state institution the Venezuelan Public Works Corporation , the Rice Plan established mechanized rice production by distributing parcels of up to 200 hectares—the minimum size deemed necessary for the successful introduction of mechanization—and generous agricultural credits . Resistance to land redistribution by larger landowners and smallholders who used state land for pasturing, was broken by the state governor who seized estates and removed landowners and smaller-scale traditional users . The Rice Plan was developed to provision growing domestic, rather than export markets. Within five years of the program’s initiation, Venezuela was producing enough rice to cover domestic consumption. Yet the growth of the sector required expansion from the existing savanna areas into Portuguesa’s adjacent tropical forests driving deforestation. While cleared forests areas initially provided higher yields, putting forested land into production required larger capital outlays, and producers adopted a strategy of diversified production, planting sesame in the dry season—rice being grown in the rainy season—and eventually integrated maize and sorghum and sugarcane into production systems . These dynamics drove increased mechanization and continued intensification of land use in the region. Alongside the national Rice Plan in Portuguesa was an agrarian colonization scheme that brought in and distributed land to European immigrants primarily from Germany and Italy. As part of the Venezuelan agrarian reform program peasants were settled next to European colonists in the colony of  Turén under the assumption that they would learn ‘modern’ and ‘rational’ cultivation techniques from the Europeans . Agrarian reform beneficiaries, however, received smaller parcels and insufficient state credit support compared to the European colonists, leading to eventually abandonment of many plots with the now landless peasants migrating to urban areas or becoming farm workers on the more successful estates . Like in the Acarigua-Araure center, agricultural expansion displaced traditional land users and drove the replacement of tropical forests with plowed fields.

Human subjects in this research are protected under the Committee for Protection of Human Subjects, protocol number 2018-04-1136 , of the Office for Protection of Human Subjects at UC Berkeley.Siskiyou is a large rural county located in the mid-Klamath River basin in Northern California . Since the mid-19th century, immigrants have historically engaged in agriculture, predominantly livestock grazing and hay production, and natural resource extraction, primarily timber and mining . Public records demonstrate that although the value of the county’s agricultural output and natural resource extraction is declining, these cultural livelihoods still shape the area’s dominant rural values of self-reliance, hard work and property rights . For instance, one county document stated that Siskiyou’s cultural-economic stability depends on nonintervention from “outside groups and governments” and residents should be “subject only to the rule of nature and free markets” . Another document, a “Primer for living in Siskiyou County” from the county administrator, outlined “the Code of the West” for “newcomers,” asserting that locals are “rugged individuals” who live “outside city limits,” and that the “right to be rural” protects and prioritizes working agricultural land for “economic purpose[s]” . We heard a common refrain that localities will eventually succumb to the allure of a taxable, profitable cannabis industry. Indeed, interviewees in Siskiyou universally reported economic contributions from cannabis cultivation, especially apparent in rising property values and tax rolls and booming business at horticultural, farm supply, soil, generator, food and hardware stores . However, a belief in an inevitable free market economic rationality may underestimate the deep cultural logics that have historically superseded economic gains in regional resource conflicts . As one local store owner told us, “I’d give up this new profit in a heartbeat for the benefit of our society.” Many long-time farming and ranching families remain committed to agricultural livelihoods for cultural reasons , even as the economic viability of family farms is threatened by increasing farmland financialization ,hydroponic gutter corporate consolidation and biophysical decline . Many interviewees felt that the recent rapid expansion of county cannabis cultivation and corresponding demographic changes were a visible marker of broader tensions of cultural continuity and endangerment.

As the sheriff expressed, cannabis cultivation would “jeopardize our way of life … [and] the future of our children” . This sense of cultural jeopardy , echoed by numerous interviewees, materialized in a range of negative quality-of-life comments about cannabis cultivation: noisy generators, increased traffic, litter and blighted properties, and unsafe conditions for residents. Non-cannabis farmers also reported farm equipment and water theft, livestock killed by abandoned dogs, wildfire danger, illicit chemical use and poisoned wildlife. Some non-cannabis farmers expressed a sense of regulatory unfairness — that their farms were subject to onerous water and chemical use regulations while cannabis growers “don’t need to follow the government’s regulations.” Enabling cannabis cultivators to pursue state licensure would facilitate just such civil regulation, but some feared that regulating this crop as agriculture would threaten “the loss of prime agriculturally productive lands for traditional pursuits” . If nothing less than the county’s culture and agricultural order were considered at stake, it is no wonder that absolute, even prohibitionist, solutions emerged in Siskiyou, with the Sheriff’s Office having a central role in defending local culture.Siskiyou’s sparsely populated landscape has been home to illegalized cannabis cultivators at least since the late 1960s, largely in remote, forested, and public lands in the western part of the county. Medical cannabis’s decriminalization in 1996 inaugurated a modest expansion of cannabis gardens throughout the county . However, for the next 19 years, Siskiyou did not establish regulations for medical cannabis, in line with locally dominant ideologies of personal freedoms and property rights. Instead, the county relied on de facto management of cultivation by law enforcement and the court system’s strict interpretation of state law . In 2015, informed by public workshops held by the Siskiyou County Planning Division, supervisors passed the county’s first medical cannabis ordinance, which seemingly balanced concerns of medical cultivators and other county residents. Regulation would be overseen by the Planning Division, which placed conditions on cultivation , limited plant numbers to parcel size and would establish an administrative abatement and hearing process for complaints.

The Planning Division, however, had been without code enforcement officers since 2008 budget cuts. Though the county authorized the hiring of one civil code officer in 2015, the Sheriff’s Office felt that the Planning Division “needed outside help” and moved to assist. Soon, the county’s limited abatement capacities were overwhelmed by vigorous enforcement and a wave of complainants. County supervisors, responding to the sheriff’s 2015 reports on the “proliferation” of cannabis gardens on private property, moved to heighten penalties for code violations, place numerous new restrictions on indoor growing and ban all outdoor growing . These strict county measures, which discarded and replaced publicly developed regulations, stoked reaction. When the Siskiyou County Board of Supervisors met in December 2015 to vote on these measures, advocates and cultivators presented 1,500 signatures to forestall its passage, a super majority of attending residents indicated opposition, and supervisors had to curtail 3 hours of public comment to vote. Despite this showing, supervisors passed the restrictive measures, prompting cannabis advocates to collect 4,000 signatures in 17 days to place the approved ordinances on the June 2016 ballot. Meanwhile, the Sheriff’s Office enforced the new stricter regulations . The Sheriff’s Office assumption of code enforcement blurred the line between noncompliance with civil codes and criminal acts. Stricter ordinances, still in effect in Siskiyou, created a broad, nearly universal category of “noncompliance.” No one we interviewed, including officials at the Planning Division and Sheriff’s Office, knew of a single cultivator officially in compliance. One interviewee estimated that growing 12 indoor plants would cost $40,000 in physical infrastructure, in addition to numerous licensing and inspections requirements, effectively prohibiting self-provisioning. The Sheriff’s Office notified the public that it would initiate criminal charges against “non-compliant” cultivators, specifically those suspected of cultivation for sale , child endangerment or suspected drug trafficking . Since the county regulations produced a situation where no one could comply, law enforcement could effectively criminally pursue any cultivator. The slippage from civil noncompliance to criminality was mirrored in enforcement practices. Investigations were “complaint driven,” meaning not only that warrants could be issued in response to disgruntled neighbors upset about a barking dog on a cultivation site, as one person reported, but that police officers could serve as a kind of permanent, general complainant and take “proactive action” when they spotted code violations .

Administrative warrants allowed deputies to enter properties with a lower evidentiary bar than they would have needed for criminal warrants, leading one patients rights group — Siskiyou Alternative Medicine — to file a lawsuit alleging county violations of Fourth Amendment protections against unreasonable search and seizure . In effect, cannabis’s criminal valences in the county endured through California’s shift of cannabis from criminal to civil provenance. Formerly illegal activities continued to be formally or informally treated as criminal matters,u planting gutter as researchers have noted with other stigmatized activities and groups, for example, after the decriminalization of sex workers in Mexico . Also, enforcement of civil matters can lead to substantive criminalization when those matters are stigmatized, as in the regulation of homelessness . While it is not unique for police officers to enforce civil codes, what is unique in Siskiyou County is the assumption of the entire civil process under the sheriff’s authority. To understand how this civil process became criminally inflected, in a county that voted for statewide cannabis legalization in 2016, one must first understand significant contextual shifts in who was growing cannabis where — and the challenge this posed to dominant ideas of land use, agriculture and culture. Since 2014, cannabis gardens have emerged on many of the county’s undeveloped rural subdivisions in unincorporated areas of Siskiyou. Subdivided into over 1,000 lots each in the 1960s, these subdivisions contain many parcels that are just a few acres in size and relatively inexpensive. Previously populated mostly by white retirees, squatters and a few methamphetamine users and makers, the parcels were often bought sight-unseen as investments or potential retirement properties, with most remaining unsold and undeveloped until the mid-2010s. In 2014, these subdivisions became destinations for Hmong Americans from several places, including Minneapolis, Milwaukee and Fresno; many of them cultivated cannabis. The inexpensive, sparsely populated, rural subdivisions enabled Hmong-Americans to live in close proximity to ethnic and kin networks, which multiple interviewees expressed was especially important for elders who had migrated to the United States as refugees after the Vietnam War. The county sheriff estimated that since the mid-2010s around 6,000 Hmong-Americans had moved to Siskiyou, purchasing approximately 1,500 parcels . In an 86.5% white county with just 745 non-cannabis farms and fewer than 44,000 people , this constituted a major demographic shift. Cannabis growers in Siskiyou’s subdivisions are especially vulnerable to detection. The subdivisions are often sparsely vegetated, dry and hilly, making them not only unproductive as agricultural lands but also highly visible from public roads, horseback, neighboring plots, helicopter and Google Earth. Green screen fencing, wooden stakes, portable toilets, generators, campers, plywood houses, or water tanks and trucks often signal cannabis cultivation but would be necessary for many land uses, especially since many lots are sold without infrastructure like water, sewer or electrical access. If detection of code violations depends upon visibility, Hmong Americans on subdivisions have been made especially visible and vulnerable to detection.

One lawyer, for instance, reported that 90% of the defendants present at administrative county hearings for code violations in fall 2015, when the first complaint-driven ordinance was put in place, were Hmong-American. One Hmong-American resident reported being stopped by police six times in 3 months and subjected to unfriendly white neighbors patrolling on horseback for cannabis — one of whom made a complaint for a crowing rooster, a questionable nuisance in this “right to farm” county. Numerous Hmong-Americans and sympathetic whites echoed these experiences. County residents confirmed their antagonism toward Hmong-Americans by characterizing them in interviews and public records as dishonest, thieves, polluters, negligent parents and unable to assimilate, and making other racializing and racist characterizations. While written regulations and enforcement profess race neutrality, in a nuisance enforcement regime based on visibility, Hmong Americans were more visible than others, leading many to argue that they were being racially profiled. Rhetoric emerging from the county government amplified racial tensions and visibilities. Numerous Sheriff’s Office press releases located the “problem” in subdivisions and attributed it to “an influx of people temporarily moving to Siskiyou” who were “lawbreakers” from “crime families” with “big money” and who threatened “our way of life, quality of life, and the health and safety of our children and grandchildren” . Just 2 days before the June 2016 ballot on the strict cannabis ordinances, state investigators responded to county reports that newly registered Hmong-American voters might be fraudulent or coerced by criminal actors and visited Hmong-American residences to investigate, accompanied by sheriff’s deputies . The voter fraud charges were later countered by a lawsuit alleging racially motivated voter intimidation; the suit was eventually dismissed for failing to meet the notoriously difficult criteria of racist intent. The raids may have discouraged some Hmong-Americans from voting, charges of fraud may have boosted anti-cannabis sentiment, and, one government official explained, “creative balloting” measures enabled some municipal voters in conservative localities to vote while others in more liberal places could not. The voter fraud charges, raids and legal contestation drew widespread media attention that further linked Hmong-Americans and cannabis. Amidst these now-overt racial tensions, the restrictive June 2016 ballot measure passed, allowing the Sheriff’s Office to gain full enforcement power over the “#1 public enemy to Siskiyou citizens … criminal marijuana cultivation” . Shortly after the June 2016 ballot measure affirmed stricter regulations, the Sheriff’s Office formed the Siskiyou Interagency Marijuana Investigation Team with the district attorney to “attack illegal marijuana grows” “mostly” around rural subdivisions . Within a month, SIMIT had issued 25 abatement notices and filed 20 criminal charges, in addition to confiscating numerous plants. Meanwhile, the Planning Division’s role had diminished — code enforcement officers were relegated to addressing violations not directly related to cannabis .

Historic water prices over the last 50 years for water deliveries from the Central Valley Project are listed in the 2000 Irrigation Water Rates Manual available at the library of the Bureau of Reclamation in Sacramento. Finally, the acreage of each district is derived with the help of geographic information systems of the irrigation district boundaries. Researchers also obtained observations on more than 15,000 groundwater wells in the Central Valley. Groundwater is a virtually unregulated resource and in many areas it provides a substitute for surface water in the event of a shortage. The depth of groundwater varies significantly, both spatially and temporally, between years and between months within a year. Researchers calculated the average well depth in the month of March, the beginning of the growing season, for each of the years 1990 to 1998 and then averaged the depths over these years. The groundwater depth at each farm location is derived as a weighted average of all well locations, where the weight is the inverse of the distance of each well to the farm to the power of 2.14—the exponent that minimizes the sum of prediction errors from cross‐validation. In the cross‐validation step each well is excluded from the data at a time and the depth is calculated using all remaining wells. There are several soil databases of potential interest to this analysis. In order of increasing detail, they are the: National Soil Geographic Database that relies on the National Resource Inventory , State Soil Geographic Database and Soil Survey Geographic Database . While SURGO is the most detailed soil database designed to allow erosion management of individual plots,there is no uniform reporting requirement for the United States. Furthermore, the observations in the June Agricultural Survey include all farms in the vicinity of a longitude/latitude pair, and hence, choosing field characteristics of one individual plot appears inappropriate. Instead,bato bucket the study uses the more aggregated soil database STATSGO, which groups similar soils into polygons for the entire United States.

Average soil qualities are given for each polygon. Although this soil database gives a first approximation of the actual average soil qualities, there might be significant heterogeneity, which is addressed in the empirical section. Finally, farmland close to urban areas has an inflated value compared to farmland elsewhere because of the option value of the land for urban development . Plantinga et al. examine the effects of potential land development on farmland prices and find that a large share of farmland value, more than 80% in major metropolitan areas, is attributable to the option to develop the land for urban uses. This study therefore constructed a variable to approximate population pressure by summing the population in each of the 7049 Census Tracts from the 2000 Census divided by the inverted square of the distance of the tract to the farm. Table 3‐1 displays the data’s summary statistics. This section presents the estimates for the hedonic regression with farmland value per acre as the dependent variable. The results are listed in Table 3‐2. The table uses feasible generalized least squares weights that account for the spatial correlation of the error terms.10Researchers conducted three spatial tests to test whether spatial correlation is indeed a problem. One test is the Moran‐I statistic . However, since this test does not have a clear alternative hypothesis, researchers supplemented it with two Lagrange‐Multiplier tests involving an alternative of spatial dependence: the LM‐ERR test of Burridge and LM‐EL test of Anselin et al. .The normal test statistic for the Moran‐I is 16.8, and the Lagrangian multiplier test are χ 2 ‐distributed with test statistics of 299 and 289, respectively. Therefore, all tests indicate that spatial correlation is indeed present. Hence the standard ordinary least squares estimate underestimates the true variance‐covariance matrix—OLS assumes all errors to be independent, even though they are in fact correlated. This suggests that standard OLS estimates of standard errors for hedonic regression equations generally might be misleading if the error terms among observations in close proximity are correlated. In fact, it is not uncommon in hedonic studies for variables to be statistically significant, yet to switch signs between alternative formulations of the model. Table 3‐2 therefore uses feasible GLS to construct the most efficient estimator by premultiplying the data by .

In the second stage, researchers estimated the model and use White’s heteroscedasticity consistent estimator to account for the heteroscedasticity of the error terms . The estimates in Table 3‐2 are based on observations with a farmland value below $20,000 per acre and water prices below $20. Including higher value observations in the analysis increases the R‐square of the regression, but the variable with the greatest explanatory power becomes population density. At the same time, the confidence levels for soil quality and water availability are reduced. Farmland with values above $20,000 per acre is generally close to urban areas, and the value of this land reflects what is happening in the urban land market, and the value of the future potential to develop this land for urban use—not what is going on in the local agricultural economy. Including these observations creates large outliers and results in estimates that are mainly driven by these outliers.Second, the research team excluded irrigation districts with expensive water prices from the analysis to get a better estimate of the net value of water. Only the net value of water, the difference between gross value and delivery cost capitalizes into farmland values. As an example, if the gross discounted value of an acre‐foot of water were $1000 and the annual delivery cost $50, the net value of the water would be zero . The researchers therefore test the sensitivity of the results to variations in water price by excluding irrigation districts with high prices from the analysis to get a better estimate of the net value of water. The coefficients on the climatic variables appear reasonable. The result for degree‐days implies that the quadratic form peaks at 1630 degree‐days. This is consistent with the agronomic literature, which indicates degree‐day requirements of this order of magnitude for several important crops grown in the Central Valley.While the coefficients are borderline significant under the feasible GLS model, the p‐value on the hypothesis that the linear and squared term on degree‐days is jointly equal to zero is 0.008, and degree‐days as a group are hence highly significant. One potential problem in the estimation using both the linear and squared variable is the high degree of colinearity between the two variables,dutch bucket hydroponic which will reduce the significance level of each individual variable. The correlation coefficient between degree‐days and degree‐ days squared is 0.98.

Another problem is that the variation in climatic variables with the Central Valley, the main growing region, is limited. In a related paper that examines the effect of degree‐ days on farmland values in the Eastern United States, the degree‐days variables are comparable in size and highly significant. Because many tree crops need cool nights, increasing temperatures substantially above the required degree‐days to grow a crop can only be harmful. The sign of the regression coefficient on water availability in Table 3‐2 makes intuitive sense: rights to subsidized surface water are beneficial. However, water rights have a price, as well as a quantity dimension. As mentioned before, only the net value of water capitalizes into farmland values. Therefore, the study tested the sensitivity of its results to variations in water price by excluding irrigation districts with high prices from the analysis, to get a better estimate of the net value of water. Restricting the sample to observations that have water rights with water prices less than $30, $40, and $50, and using no price restriction at all decreases the value of an acre‐foot from $809 in Table 3‐2 to $625, $583, $524, and $395, respectively, as the hedonic regression only picks up the net benefit of the water right. The linearity of the coefficient on water rights is confirmed when dummies for different ranges of water rights are included.14 The sample includes districts with zero private or federal water rights. These are districts that depend primarily on groundwater and state water. Since state water is very expensive, it is excluded from the estimation.15 Finally, a greater depth to groundwater is harmful, as it would result in larger pumping costs, but the coefficient of this variable is not significant. Soil variables have intuitive signs as well, and four of the five soil variables are significant at the 5% level. Higher values of the variable K‐factor indicate increasing erodibility of the top soil. Similarly, a higher clay content is also less desirable, as is low permeability, which indicates a soil that does not hold water. Finally, population density has a big influence on land prices: this variable is highly significant and of a large magnitude compared to the sample mean. The potential to sell agricultural land for urban development is often the most profitable option for farmers. The research team conducted several sensitivity checks, which are listed in Appendix 1. The results on water availability are remarkably robust, while the results for the variable degree‐ days are more sensitive to the particular implementation. However, the latter might be explained by the limited climatic variation in this project’s sample study. The team conducted a similar analysis for the Eastern United States with much larger variation in climatic variables, and find results that are again very robust and similar to the ones presented above. The coefficients on the climatic variables can now be used to calculate the impact of climate change on farmland values in California.

The impact of climate change on farmland values can be derived by evaluating the hedonic function both at the current climate and at a new predicted climate.First, note that a decrease in availability of federal and surface water would have a large and significant impact on the value of farmland. The coefficient on water availability is between $400–$850 per AF, depending on the price a district pays for water.Because researchers modeled surface water availability as additively separable from other exogenous variables, the impact is easily derived as the product of the value per AF and the decrease in water availability.As mentioned before, recent hydrological studies for moderate‐temperate climates utilizing a smaller geographic scale discovered that despite the increase in annual precipitation, the runoff during the main growing season , might actually decrease as a seasonality effect dominates the annual effect.The decrease in runoff translates into decreasing surface water availability, where the magnitude depends on the seniority of water rights. More senior water rights holders always get served first and are hence less prone to a decrease in water availability. For the same reason, junior rights holders will face potentially large reductions in availability. Given that the estimated value for cheap water is $809 per AF, a modest reduction of just 0.5 AF per acre will lower the value of the affected farmland by approximately $400 per acre. In this study’s degree‐day model, changes in temperatures have nonlinear effects on the resulting number of degree‐days. In fact, the study’s approach is conservative in the sense that temperatures above the upper threshold b2 = 32°C are assumed to have no impact on plant growth and 35°C are the same. The approach therefore assumes the marginal effect of further temperature increases to be zero, while some agronomic studies argue it should be negative.Table 3‐3 lists the average area‐weighted impact of a change in climatic conditions for three uniform temperature increases.The research team used the coefficient estimates from Table 3‐2 that corrects for the spatial correlation of the error terms.For comparison, the area‐weighted value of all observations in this study’s sample is $4,265. On average, the value of farmland in California would decrease by $482 per acre, or around 11%, under the hottest 3°C increase scenario. However, the distribution of impacts is quite different, ranging from large damages to modest benefits. Existing areas with a very hot climate—especially farms in the Imperial Valley—would face much larger relative decreases in value, while farmland around the Delta with its natural cooling mechanism would benefit slightly from an increase in temperatures, and hence degree‐days. Given the linear structure of the hedonic equation, the aggregate impact is simply a linear combination of the regression coefficients, and hence is itself normally distributed.