文档介绍：. Watson et al. 239
Soil Use and Management (2002) 18, 239±247 DOI:
Managing soil fertility anic farming systems
*, , , . Jackson3 & . Rayns3
Abstract. Complex relationships exist between ponents of anic farm and the quantity
and quality of the end products depend on the functioning of the whole system. As such, it is very dif®cult
to isolate soil fertility from production and environmental aspects of the system. Crop rotation is the central
tool that integrates the maintenance and development of soil fertility with different aspects of crop and live-
stock production anic systems. Nutrient supply to crops depends on the use of legumes to add nitro-
gen to the system and limited inputs of supplementary nutrients, added in acceptable forms. Manures and
crop residues are carefully managed to recycle nutrients around the farm. Management of anic mat-
ter, primarily through the use of short-term leys, helps ensure good soil structure and biological activity,
important for nutrient supply, health and productivity of both crops and livestock. Carefully planned
diverse rotations help reduce the incidence of pests and diseases and allow for cultural methods of weed
control. As a result of plex interactions between different ponents, fertility management
anic farming relies on a long-term integrated