Demand-Driven Technologies for Sustainable Maize ... - IITA

124chimique. L’effet relatif de l’application de la fumure organique étaitdans l’ordre suivant: fumure de vache > tiges de M. pruriens > élagagesde L. leucocephala > résidus de maïs. Le pourcentage moyen d’engraiséquivalent aux applications des matières organiques était de 24, 18,12, et 11% pour la fumure de vache, tiges de M. pruriens, résidus demaïs, et élagages de L. leucocephala respectivement. Les résultats ontmontré que dans des systèmes intensifs, une combinaison de 5 tonnesfumier de vache ha -1 et des taux d’engrais inorganiques optimumrecommandés, pourraient permettre d’atteindre les rendements élevésescomptés. En conclusion, dans les conditions de faibles intrants et dansles systèmes défi cients en nutriments, l’application de fumier de vacheou de tiges de M. pruriens, pourrait mieux réduire les exigences enengrais inorganiques de la culture de maïs.IntroductionSole-planted maize (Zea mays L.) and maize-based cropping sequencesare predominant cropping systems in the Nigerian savanna. Followingthe development and availability of extra-early maize varieties tofarmers, maize production has expanded to new frontiers within thesavanna. However, low inherent soil fertility and/or declining soil fertilityis a major factor limiting grain yield of maize in the Nigerian savanna.Most of the soils are highly weathered and poorly buffered with meagrereserves of nutrients in the rooting zone. A large part of the savannasoils are, therefore, susceptible to nutrient depletion with intensivefarming because of their low buffering capacity (Balasubramanianand Nnadi 1980; Kang and Wilson 1987). Although the applicationof inorganic fertilizers is an effective means of increasing crop yieldsin arable systems, fertilizer costs, amongst other constraints, preventfarmers from using them in recommended quantities and balancedproportions. On average, the estimated amount of inorganic fertilizer(N, P 2O 5and K 2O) available to and used by farmers in Nigeria isabout 4.5–5.6 kg nutrients ha -1 arable land (Ofori and Sant’Anna1990; Ange 1995; Dudal 2002), an amount that is far below therecommended rates for maize and, therefore, insuffi cient to meetcrop nutrient demands. There is increasing evidence that the mostpromising way to improve crop yields, especially in smallholderfarming systems, is by increasing inorganic fertilizer use effi ciencythrough the addition of organic amendments (Jones et al. 1997;Uyovbisere et al. 1999). Vanlauwe and Sanginga (2004) indicatedthat this approach was driven by the lack of a suffi cient amount ofeither inorganic or organic amendments, the recognition that bothinorganic and organic amendments fulfi l a set of different functionsand the potential for creating added benefi ts when applying organicresources in combination with inorganic amendments.