Cereal yield response to conservation agriculture practices in drylands of West Africa: A quantitative synthesis

Abstract

a b s t r a c tTo address the decline in crop productivity in the drylands of West Africa, many initiatives have focused on combating soil degradation. Various practices including (1) parkland trees associated with crops, (2) coppicing trees, (3) green manure, (4) mulching, (5) crop rotation and intercropping, and (6) traditional soil/water conservation have been tested. The present study attempts to provide a comprehensive, quantitative synthesis of existing reports on the effect of conservation agriculture (CA) practices on crop yield response in Burkina Faso, Mali, Niger and Senegal. Out of a total of 155 reports found, 63 fulfilled all the appropriate criteria to be included in the meta-analysis of the effect of various conservation agriculture practices on the yield response of maize, millet and sorghum. The study revealed significant variability in cereal yield response (and hence risk) with all the practices examined. Despite the variability, the mean effects of the six CA practices on crop yield were more positive than negative except with parkland trees. However, for this last practice, species like Faidherbia albida exerts more positive impact on crop yield. Yield increases relative to the control were higher with green manure and mulching than with coppicing trees and parklands. Increases in yield in the six CA practices were higher on low to medium productivity sites for maize, millet and sorghum. Coppicing trees and rotations improved yields when the rainfall is >800 mm whereas the opposite happens with parkland and soilewater conservation measures. Mulching performed better when the rainfall is <600 mm. The variability (and hence yield risks) calls for more understanding of the processes and application of appropriate tree management to reduce crop yield losses while still providing products (fruits, leaves, wood, etc.) and services (soil carbon building up) for long-term sustainability of the production systems in drylands of West Africa.

Management of crop water under drought: a review

“…In more subhumid conditions, however, legume cover crops, often established within relay intercropping system, could offer possibilities to alleviate N-fertilizer constraints and improve soil fertility. Bayala et al (2012) studied conservation agriculture in semi-arid tropics and showed that cover crops were found at sites with rainfall higher than 600 mm, while positive yield effects were reported when rainfall exceeded 800 mm.…”

Climate Smart Agriculture as Final Goal: Use of Improved Cereals Varieties in Cinzana, Mali.

“…In fact, 20 to 40 percent of annual rainfall is lost as runoff leading some times to severe erosion (Tacko Kandji et al, 2006) and globally only 10% -15% of rainfall will be used by crops for transpiration (Bationo and Buerkert, 2001). To tackle the problem , several, proven soil and water conservations techniques that restore degraded lands and improve water infiltration in the soil (Gigou et al, 2006;Zougmore et al, 2014) and agroforestry technologies that restore soil fertility and control soil erosion were also developed (Bayala et al, 2012) to help farmers adapt to climate change.…”

Implications of tillage practices, management of soil surface and fertilizer application on sustainable dryland agriculture: A case study of Eastern Rwanda

“…Results from this study support Vanlauwe et al (2014) who suggested that the appropriate use of fertilizer should be considered as a fourth principle of CA in order to enhance crop productivity in addition to three that currently define CA which are minimum disturbance of soil, keep soil cover and crop diversification. The early effects of tillage on yields can be attributed to the site potential as reported by Bayala et al (2012) that conservation agriculture treatments have positive effects on yield in poor to medium soil quality than in high quality soils. This raises the need for assessment and understanding the effects of CA under different ecological and socio-economic conditions as suggested by (Giller et al, 2009).…”