Soil fertility trends and management in Conservation Agriculture : a South African perspective

Conservation Agriculture (CA) is an integrated approach that consists of a suite of practices, namely no-till farming, cover crops, and crop rotation that includes at least three crops. In the global context, CA is implemented widely in South America (Argentina and Brazil) and North America (United States and Canada), with smaller proportions in Australia and New Zealand. There is little implementation of CA elsewhere in the world mainly because of natural resource constraints. Benefits of the system include increases in soil organic matter and related increases in organic N in soils. Experimental results show extremely strong stratification of important plant nutrients, particularly P, K and Ca, at very shallow soil depths (