Managing soil fertility in organic farming systems

12 Complex relationships exist between different components of the organic farm and 13 the quantity and quality of the end products depend on the functioning of the whole 14 system. As such, it is very difficult to isolate soil fertility from production and 15 environmental aspects of the system. Crop rotation is the central tool that integrates 16 the maintenance and development of soil fertility with different aspects of crop and 17 livestock production in organic systems. Nutrient supply to crops depends on the use 18 of legumes to add nitrogen to the system and limited inputs of supplementary 19 nutrients, added in acceptable forms. Manures and crop residues are carefully 20 managed to recycle nutrients around the farm. Management of soil organic matter, 21 primarily through the use of short-term leys, helps ensure good soil structure and 22 biological activity, important for nutrient supply, health and productivity of both 23 crops and livestock. Carefully planned diverse rotations help reduce the incidence of 24 pests and diseases and allow for cultural methods of weed control. As a result of the 25 Archived at http://orgprints.org/8060 complex interactions between different system components, fertility management in 1 organic farming relies on a long-term integrated approach rather than the more short2 term very targeted solutions common in conventional agriculture. 3 4