Influence de la date du semis du niébé sur le rendement du cotonnier dans l'association cotonnier-niébé

Résumé

In the Northern Cameroon, cotton (Gossypium hirsutum L.) and cowpea (Vigna unguiculata L. Walp.) are being intercropped to an increasing extent, with cowpea crops benefitting from cotton pesticide treatments. Trials were conducted to determine the optimum planting time for cowpea when intercropped with cotton: simultaneous sowing of cotton and cowpea; sowing of cowpea at the first cotton weeding; and sowing of cowpea when the cotton ridges were formed. With simultaneous sowing, the mean cotton yield was 50% less than under monocropping conditions. Cotton yield was reduced by 16% and cowpea yield by 54% when cowpea was sown during the cotton ridging process. We thus recommend sowing cowpea when the cotton ridges are formed, i.e. approximately 5-6 weeks after the cotton crop is sown. Contamination of cowpea crops by cotton pesticides should be considered in this respect.