The meta-analysis by an international agricultural think tank says all three components of Conservation Agriculture (CA) must be used for long-term success. Proper levels of fertilizer are key for the greatest increases in yields. The yield benefits were lower in dry climates. CA works better on loamy soils than on sandy or clay soils. In poorly drained soils, mulch can cause waterlogging. In some regions, farmers prefer to use crop residues as livestock fodder or as cooking fuel. And, the market for some crops, such as legumes, used in the rotation is limited in some countries so farmers see little profit in them.
“Providing tailored advice for each region and despite evident advantages in many situations, CA may not be the solution for all,” says a summary by the Consultative Group on International Agricultural Research, although the technique “has a crucial role to play.”