Among the thirteen growth models the two-linear model describes the weight gain of piglets from organic farming best. This model aims at two different growth periods which actually are caused by the general conditions of the piglets’ rearing. From this moment on the piglets have no longer the opportunity to suckle milk. This implies that solid feed is the only food source and likewise water is the only source of liquid. Due to the loss of the familiar surroundings the piglets furthermore have to cope with new drinking and feeding troughs, new stable mates, new climate control and also a new germ flora. In addition to the stress attributable to weaning the immune protection of the maternal antibodies that were ingested with the colostrum directly after birth decrease and the piglets’ own immune system is still under development. In this context sometimes antibiotics are administered prophylactically in intensive livestock farming. This is not standard in organic farming with the result that in the first days of post-weaning the weight gain declines or stagnates completely.

Not until after coming through that period piglets show an increased weight gain, what corresponds with the point of intersection of the two straight lines of the model at an age of about 50 days. In contrast to De Behr , who described a step-wise linear growth model for Belgian Blue cattle less than 20 month of age, the point of intersection was not fixed in advance, but it was determined from the growth data only through the goodness of fit. The Mediterranean region has been cultivated for millennia and is the site of the evolution of settled agriculture and the center of origin of a range of important crops . Over the centuries, soils have been slowly but continuously degraded by removal of nutrients in harvest products, by intensive grazing and/or soil erosion. Adverse climatic conditions of variable and frequently inadequate rainfall and a long dry season characteristic to the Mediterranean climate render the region’s landscape vulnerable to over-exploitation and further degradation . In recent decades, agricultural production has intensified in the Mediterranean region, especially the increase with continuous cropping instead of fallow and application of mineral fertilizer.

To mitigate the negative impact of such intensification, various management practices have been developed, such as rotations as an alternative to mono-cropping , reduced tillage or no/zero tillage instead of conventional tillage, the production and use of compost from manure, straw and other organic residues or development of fertilizer best management practices . In a major shift from conventional production systems, conservation agriculture systems, embracing ZT for minimal soil disturbance, surface residue retention and crop rotation, have been adopted extensively in Australia, Canada, the USA and Latin America . This development has been driven by labor and energy savings, control of soil erosion, better soil moisture conservation  and the opportunity for earlier sowing and better yields. In addition to soil conservation, CA systems in the majority of cases have been shown to increase the amount of soil organic matter, which improves soil quality and the environmental sustainability of agro-ecosystems. The build-up of SOM involves sequestration of carbon , which may contribute to mitigation of increasing atmospheric CO2 levels , even though the potential contribution may be limited. Uptake of CA by farmers in the Mediterranean region is lagging behind uptake elsewhere in the world, even in countries such as Morocco and Tunisia where considerable research has been done . Only during the last few years some progress has been achieved .

Retention of residues in agro-ecosystems where livestock play an important role is a potential obstacle to CA adoption. In the Mediterranean region of West Asia and North Africa , sheep and goats are an integral part of farming systems – and crop residues are a crucial part of small ruminant’s diet, especially during the dry season . To address some of these issues, the International Center for Agricultural Research in the Dry Areas has carried out experiments on-station or demonstrations with farmers, to test ZT and residue retention and their impact on crop yield . Few studies have been published so far focusing on soils of the Mediterranean region and how they are affected by ZT/CA practices. Therefore, in the long-term ZT/CA trials at ICARDA’s headquarters at Tel Hadya in Syria, a range of soil quality indicators were regularly monitored during 2008 to 2012, to help explain increases in crop yields that were observed under the various ZT systems. The study also sought to identify suitable indicators of increased soil quality, and quantify the amount of C that can be sequestered under partial residue retention and the impact of surface residue on soil moisture conservation and soil water evaporation.In the B4 trial, the effects of tillage and early and late planting were tested in a four-course rotation of wheat, chickpea, barley, and lentil.