Long-Term Effects of Crops Residues Management on the Soil Chemical Properties and Yields in Cotton - Maize - Sorghum Rotation System in Burkina Faso

In cotton and cereals production systems, the most important cause of soil fertility degradation is the inappropriate crop residues management. In a long-term experiment carried out from 1982 to 2012, the effects of crop residues management (CRM) during 30 years on soil chemical properties and crops yields were evaluated in a cotton-cereals rotation. The experimental design was nonrandomized blocks having 3 treatments. Extensive CRM with exportation of residues was compared to semi-intensive CRM and intensive CRM and recycling the residues into compost and farmyard manure, respectively. The results showed that continuous cropping of soil during 30 years affects significantly (p <0.05), the main chemical characteristics of soil for comparing crop residues management practices. From 25th to 30th years, the decrease of carbon, Nitrogen and total P contents was very high as well as those of exchangeable bases, particularly, Ca2+ and Mg2+ contents. The cation exchange capacity (CEC) decrease was 63, 31 and 26%, respectively in extensive, semi-intensive and intensive CRM. Recycling crop residues into compost or farmyard manure does not prevent soil chemical degradation and crops yields decrease but allowed to reduce them significantly. Moreover, integrated management of crop residues, a reduction of soil tillage frequency and preventing soil erosion are suggested for a sustainable maintenance of soil chemical properties.