Variation in maize yield gaps with plant nutrient inputs, soil type and climate across sub-Saharan Africa

Despite the number of site-specific studies conducted on the effect of inorganic fertilizer and organic inputs on maize yield, information is lacking on the variation in yield risks with soils and climate in sub-Saharan Africa (SSA). Information on yield risk could give an idea of where a particular input may not work well, and thus has low potential for adoption by farmers. Using analytical methods combining features of meta-analysis, response surface regression and generalized additive models, this work synthesizes information on variation of maize yield gaps and risks with inorganic fertilizer and organic inputs in relation to soils and climate. The organic inputs included in situ green manure from sunhemp (Crotalaria spp), velvetbean (Mucuna spp), sesbania (Sesbania spp), tephrosia (Tephrosia spp) and gliricidia (Gliricidia sepium). Yield gap (YG) was defined as the difference in grain yield between maize grown using a given nutrient input and without external nutrient inputs (i.e. control) under a specific study condition. Yield risk was defined as the probability of obtaining yields lower than or equal to the control across similar conditions. Yield gaps with the recommended rate of inorganic fertilizer were significantly higher on farmers' fields compared with research stations, while with organic inputs such differences were smaller. With inorganic fertilizer, yield risks were higher (up to 22%) on Nitosols (one of the most fertile soils), compared with Luvisols (

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DOI:

https://doi.org/10.1016/j.fcr.2009.11.014

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