Efficacy of the association of cover crops with maize and direct sowing short-term effect on crops? yields in maize-cotton cropping system in Western Burkina Faso.

Abstract

To improve the productivity and sustainability of cotton and cereals based system, direct sowing under mulch was tested for its efficacy on cotton and maize yields on the research station of Farako-Bâ, in Western Burkina Faso. The experimental design was a complete randomized blocks of Fisher with four replications. Conventional tillage by annual moldboard plowing (T7) was compared with direct sowing under mulch-based cropping system (DMC) using maize association with cover crops defined as: maize without cover crop (T1), maize + Brachiaria ruziziensis (T2), maize + B. ruziziensis + Mucuna cochinchinensis (T3), maize + B. ruziziensis + Panicum maximum (T4), maize + B. ruziziensis + Stylosanthes hamata (T5), and maize + Crotalaria juncea (T6). Cover crops were planted 21 days after maize emergence between the rows of this main crop. The biomass produced by the cover crops and maize straws were evaluated as well as maize and cotton yields, during the first 6 years of the study, from 2010 to 2015. Results showed that among cover crops, the biomass production was significantly lower with C. juncea. The associations of cover crops with maize increased significantly the production of total dry matter compared to plots without cover crops, in the conventional tillage. Association with cover crops did not influence significantly nitrogen, phosphorus and potassium contents of maize and the maize’s yields even if the depressive effects were recorded. Compared to the conventional tillage, the DMC appeared also effective on seed cotton yields even without a significant improvement during the 6 first years of the study. These promising results, confirm the feasibility in tropical conditions of DMC which must be continued to better analyze its long-term effects on soil properties. Key words: Cover crops, mulch-based cropping system (DMC), conventional tillage, biomass, yield.