LASSOCIATION MAIS-NIEBE ET LA RESTITUTION ORGANIQUE SONT-ELLESLE MOTEUR DUNE GESTION DURABLE DES SOLS A LOUEST DU BURKINA FASO ?

Are maize-cowpea associations and organic restitution the driving force behind sustainable soil management in western Burkina Faso? Soil fertility management is one of the key factors in the sustainability of cropping systems in western Burkina Faso. With this in mind, a study was carried out on the management of crop residues, fertilization and the inclusion of legumes in the cropping system. The aim was to determine the effects of mulching, insertion of cowpeas into the cropping system and organo-mineral fertilization on soil fertility. The experimental design was a strip split plot with 4 replications and three treatments corresponding to 3 crop residue management methods, 3 cropping systems with or without maize and cowpea, and 2 types of fertilization. Trials were conducted from the 2018 to 2020 cropping seasons. Soil moisture, the number of fungal and bacterial colonies and soil chemical characteristics were determined in 2020. The results show a significant increase in soil moisture on maize-wheat association plots of 9.28 and 8.58% for the 0-20 cm depth and 6.85 and 5.31% for the 20-40 cm depth respectively compared with pure maize and cowpea cultivation. For crop residue management and fertilization, soil moisture levels were identical for all treatments. Concerning soil micro-organisms, the results show that five (05) types of fungi were identified on the different treatments: Aspergillus flavus, Aspergillus niger, Fusarium moniliforme, Geotrichumcandidum and Trichoderma sp. The results obtained show no significant difference between treatments at the 5% threshold, either for fungi, bacteria or soil chemical characteristics. Consequently, the maize-cowpea association can be considered a sustainable soil fertility management practice in the western region of Burkina Faso. However, the choice between recycling crop residues by mulching and applying organo-mineral fertilizer must be determined by the farms themselves, according to their socio-economic reality.