Ten mL of the upper layer was transferred to a 15 mL centrifuge tube containing 500 mg of Primary Secondary Amine and 1.5 g of anhydrous magnesium sulfate.The centrifuge tube was shaken for 30 s followed by centrifugation for one min.at 1500 rpm.Six mL from the upper layer was taken, concentrated to dryness using Turbovap , and the final volume was made up to one mL using n-hexane and analyzed by Gas Chromatograph.For recovery studies, pesticides at two levels organochlorines at 0.01 and 0.05 mg kg−1 and organophosphates at 0.025 and 0.125 mgkg−1 were undertaken.Certified reference materials of pesticides were purchased from Sigma Aldrich and stock solutions were prepared using pesticide grade solvents.Single laboratory method validation was carried out to found the recovery of pesticides.Spiking solutions were prepared from stock solution for measuring percentage recovery.For calibration were undertaken with six levels of serially diluted standard mixture prepared from stock solutions.Based on these working standard solutions, calibration curves were obtained and were used to evaluate the linearity of the gas chromatograph response helps to quantify the pesticide residue of the samples.The data on the moisture and nutrient composition of different types of weeds used in the study are illustrated in Table 2.0.Among the different types of weeds, moisture content varied from 68.8 to 86.7%, with higher value in mikania and lower in macranga.Normally a certain amount of moisture is essential for composting because the main site of microbial activity is in the thin water film on the surface of particles.The chemical nature of all the weeds under study was acidic in reaction with pH values varying between 5.1 and 6.3.

Content of oxidizable OC in general varied from 30.6 to 55.0%, higher values with lantana and lower with mikania.As in the case of oxidizable OC, relatively higher N was also observed in lantana followed by macranga , chromolaena and mikania.C:N ratio was almost similar in all the species,hydroponic nft ranging between 26.0:1.0 and 30.0:1.0.However, the substrate materials with higher N content or with narrow C/N ratio are always desirable in decomposition process, since N is supposed to promote the multiplication and activity of microorganisms, there by shooting up the decomposition at an increasing rate.Among the other major nutrients, P varied between 0.09 and 0.29%and K between 1.8 and 2.2%.Both P and K were higher in chromolaena.The percentage content of important mineral nutrients did not vary widely between the weeds, whereas the C:N ratio of the weeds varied between 26.0 and 30.0, the desired value being 25.0–30.0.The optimal start up conditions helps to promote the decomposition of weeds.The proper balancing of nutrients, content of moisture and aeration were noted as essential factors for effective conversion to humic mass.All the weeds such as chromolaena, lantana, macaranga and mikania used as feed stock in this study meet the required C:N with adequate content of nutrients.Temperature is one of the most important indicators, which rebound in the process of decomposition of organics and changes in microbial activities.The change in temperature occurred in the weed biomass with the elapsed time are illustrated in Fig.1.This figure portrayed that the temperature in the weed stack, applied with various inocula viz; cow dung, urea, microbial consortium and jeevamrutham got elevated and reached to a peak of about 54.0 °C, 63.0 °C, 53.0 °C and 66.0 °C respectively after 10 days of decomposition process while the control pile remained with 48.0 °C.It was also noted that all the piles attained thermophilic temperature shortly after stack establishment.The temperature in the weed biomass applied with urea, microbial consortium and jeevamrutham reached the highest levels on 3rd day and continued to remain at higher levels in the following days.This high temperature was enough for destroying the microbial pathogens, and to assure rapid degradation of weeds.During the formation of humic substance, the heap applied with urea attained the highest temperature at 4th day and the lowest at 50th day of composting.However, the maximum temperature attained in the heap applied with jeevamrutham was on par with urea and microbial consortium, and the same heaps attained a temperature of >70.0 °C on 3rd day itself, which is definitely due to the intense activity of microorganisms.During the initial activation days, the simple organic compounds such as sugars are mineralized by microbial communities and produced CO2, NH3, organic acids and heat.The optimum range of temperature in the decomposition process was 40.0–65.0 °C allowing to kill pathogens above 55.0 °C.During this phase, thermophilic microorganisms deteriorate cellulose and lignin in the substrate materials.

Finally, during the maturation stage, the temperature slowly decreased owing to the reduced microbial activity resulting from a diminishing stock of biodegradable compounds.The hike in temperature during the initial days of the experiment is due to mineralization and transformation of organic matter,whereas in the later stage, the stabilized condition resulted in scaling down the production of heat.The initial boosting of temperature varying between 48.0 °C and 72.0 °C within a short time of stack establishment in this study is due to the intense microbial activities triggered by the application of additives; cow dung, urea, microbial consortium and the farm derived microbial formulation.Normally, temperature varies over time and by the shape of the decomposing stack, and followed a pattern consistent with degradation of organic feed stock by microorganisms.In the last phase of maturation, bacterial numbers decline and fungal population increases in all the treatments as easily decomposed material got exhausted.At this stage recalcitrant materials dominate and temperature decline to the ambient level.Application of additives to decomposing organics is supposed to have significant impact on the period of decomposition.In the present study, the time taken for decomposition of weed biomass without any additives was 120 days.But, the period got reduced to 100, 70, 94 and 75 days with the addition of cow dung, urea, microbial consortium and jeevamrutham respectively.Application of microbial consortium and jeevamrutham could reduce the decomposition period from 120 days to 70–75 days, while the reduction was only up to 100 days with cow dung.The intense activity of vast numbers of microorganisms such as bacteria, fungi and actinomycetes coupled with relatively higher content of N, contributed from cow urine as well as pulse flour might be the probable reason for intense decomposition and subsequent reduction in jeevamrutham applied piles.Results of the study pointed out that microbial formulation namely jeevamrutham was equally effective with laboratory produced microbial consortium in reducing the period for converting weed biomass to humic substance.Moreover, the practice of application of urea during the process of decomposition can be eliminated by the use of microbial inoculum.Quality evaluation of humic mass produced from weeds was carried out with respect to various basic physico-chemical properties, nutrient potential, and presence of toxic contaminants.Those humic substances in general were with acceptable color, i.e., coffee brown.The heat generated during the initial period of experiment is believed to have profound effect on the color of the final product.

The heat generated during the process generally depends up on the type of feed stock and activity of microorganisms.The coffee brown color of humic substances generally indicates high content of OC, which is considered as the key factor for organic farming.The content of moisture in the final humic substances were 20.3%, 20.8%, 22.3%, 22.1% and 23.6% in control, cow dung, urea, microbial consortium and jeevamrutham applied treatments respectively.The higher content of moisture was associated with jeevamrutham applied treatment and lower in weed biomass alone.In the composting technology, moisture content between 40.0–60.0% of raw materials is normally recommended for the success of composting.Biological activity will be slow if the compost heaps start to dry and virtually cease if it dries out.During the maturation stage, lower moisture content is desirable as the compost become lighter, hydroponic channel making it easier to mix and increasing the shelf life.Content of moisture in the compost samples normally varied with the type of the raw material and season of the climate.According to the FAI , 15.0– 25.0% is the desired level of moisture in the finished composts.Moisture content less in the composts may not have been stored for longer period due to the preeminent moisture loss, whereas the excessively dry composts is usually dusty and unpleasant to handle.The bulk density of composts varied from 0.56 to 0.82 g/cm3 dry matter, with highest values with control.Application of various inocula could reduce the bulk density of final compost as observed in the treatments with urea , microbial con-sortium , cow dung and jeevamrutham.According to Indian regulatory rule of organic manure, bulk density is measured on dry weight basis as an indicator of particle size, and also indicates organic matter as well as inert material/ash content.The lower bulk density of the composts is desirable because it helps to increase the water holding capacity of soil when applied continuously for longer period of time.The important chemical characteristics of humic mass such as pH, TOC, oxidizable OC, N, C/N are given in the Fig.6.pH is an important property deciding the quality of this final decomposed product.In the present study the humic mass produced in all the treatments were alkaline in reaction with the values varying between 7.7– 8.3.

The lower pH was reported in weed biomass alone and the higher value in the treatment applied with jeevamrutham.Compared to the substrate materials, pH was high in the finished products of all the treatments.A good quality compost is supposed to have a pH between 6.5 and 7.5.However, considering the acidic nature of the soils of Kerala, the matured decomposed mass with pH more than 6.0 are beneficial for improving the chemical condition of the soil.pH was found to scale down at the end of decomposition, and this decline is mainly due to the volatilization of ammoniacal N and hydrogen ions released through the nitrification activities of nitrifying bacteria as well as the emission of large volumes of CO2.Carbon farming is mainly intended to enrich the soil with carbon, which is mainly dictated by the total organic carbon and dichromate oxidizable OC, and the values in this study varied between 22.8 – 39.4% dm and 19.6 – 33.8% respectively.There has been a strong relationship between oxidizable organic C and TOC valuesin the humic mass produced from weeds.They were with higher content of TOC obviously due to the higher carbon stock in the feed stock.As per the FAI guide lines, the oxidizable organic C in an ideal compost for soil application must be ≥ 16.0%.The decline in oxidizable organic C observed during the process of decomposition is definitely due to the microbial decomposition of organic substrates , as microorganisms consume carbon for energy.A decrease of oxidizable OC was considered as an indicator of maturity and stability of composts.C/N ratio is an important property governing the quality of humic substances produced after decomposition, the ideal value being < 20.0:1.0.The C/N ratios of most of the humic mass produced in this study were below 16.0:1.0, indicating a relatively higher content of N than C, which automatically leads to faster mineralization process, on application to soil.The CFU values of bacteria, fungus actinomycetes were more in the humic mass produced using farm derived jeevamrutham and comparatively very less in control and urea applied treatment.The treatment with microbial consortium ranked second after jeevamrutham.The species isolated were Bacillus sp, Pseudomonas sp, Erwinia sp.etc.Among these, Bacillus sp.are normal inhabitants in soil.Some fungal pathogens were present in all the samples and the major fungal species were aspergillus, rhizopus, mucor etc.The fungi Fusarium oxysporium was isolated from the treatment without any inoculum.These organisms prevent the proliferation of bacterial pathogens by increasing temperature, and thus facilitating the growth of thermophilic microbes.The phenolic and carboxylic acid groups of phyto chemicals present in the humic mass are also supposed to impart resistance against pathogens.The world population is expected to increase to 9.5 billion people in the next 40 years.This calls for an increase of over 60% in food production worldwide at least by 2050 to combat the crisis faced by the continuously increasing population.Unfortunately, natural resources such as: land meant to sustain food production and meet the demands of such an expected population increase are diminishing coupled with the high cost of the limited existing land.