On-farm evaluation of the contribution of sole and mixed applications of organic matter and urea to maize grain production in the Savannah.

Abstract

The study was conducted in research villages in the derived savannah (DS) and northern Guinea savannah (NGS) benchmark areas of the Ecoregional Programme for the humid and sub-humid tropics in Sub-Saharan Africa to investigate the possible benefits of combining organic matter with urea under a range of on-farm conditions. Biophysical and socioeconomic characteristics of the area are discussed. The maize response to combined applications of organic matter and urea in on-station field trials at four locations (Bouaké, central Côte d'Ivoire; Glidji, southern Togo; Sékou, southern Benin and Zaria, northern Nigeria) and the maize grain yield in a researcher-managed on-farm trial in two villages (Eglimé and Zouzouvou) in the DS benchmark area, southern Benin, and in two other villages (Kayawa and Danayamaka) in the NGS benchmark area, northern Nigeria, are presented and discussed. In the DS, a 2-year farmer-managed trial was initiated in 1999 by the Research and Development branch of INRAB in southern Benin, wherein cowpea was used as an in-situ source of organic matter. In the NGS, demonstration trials were initiated at seven states of the northwestern and northeastern Nigeria. Preliminary yield data support observations made earlier under on-station and researcher-managed on-farm conditions: maize grain yields in the sole fertilizer treatment were similar to yields in the mixture treatment in which approximately 40% of the fertilizer N was substituted by manure.