A meta-analysis of long-term effects of conservation agriculture on maize grain yield under rain-fed conditions

Conservation agriculture is often encouraged for use in rain-fed maize systems in Southern Africa. The purpose of this meta-analysis is to identify the factors on maize yield in these conditions. Twenty-six studies lasting over 5 years were analyzed. Results indicate much variability and dependence on multiple influences on yield, such as rainfall, mulch cover, soil texture, nitrogen inputs, and climate. Some results include: mulch cover in high rainfall areas leads to lower yields, well-drained soils are necessary in order to see improved yields over time, and higher nitrogen inputs are necessary to achieve higher yields. The authors conclude that conservation agriculture and its related techniques must be adapted to specific biophysical conditions in order to have a beneficial impact on maize yields.