Rainfed rice response to fertilizer in the Sudan Savanna of West Africa

Abstract

In West Africa, rice (Oryza sativa L. and Oryza glaberrimaI Steud) production is not meeting current demand. Low yields are attributed to diverse biotic and abiotic constraints including nutrient deficiencies, inadequate agronomic practices, and socioeconomic constraints. This study quantified yield and profit responses of rainfed rice produced in the Sudan Savanna of Burkina Faso and Mali to fertilizer N, P, K, and Mg-S-Zn-B treatment. The mean yields were 2.2 and 2.4 Mg ha-1 for upland rice in Finkolo and for lowland rice in Longorola in Mali, respectively, and 1.5 and 2.2 Mg ha-1 for upland rice at Boni and Karaba in Burkina Faso. Lowland rice grain yield was not affected by nutrient application at Longorola. The grain yield increases with 30 and 60 kg ha-1 N were, respectively, 0.30 and 0.48 Mg ha-1 at Karaba, 0.21 and 0.34 Mg ha-1 at Boni, and 0.32 and 0.41 Mg ha-1 at Finkolo indicating similarity in response. Grain yield response to P was observed only at Karaba. If fertilizer were applied at 50% rather than 100% of the economically optimum rate, as might be the case for financially constrained farmers, the mean yield increase was 36% less but agronomic efficiency was 23% higher and the profit cost ratio was 66% higher. There was no response to K or to Mg-S-Zn-B. The results, therefore, indicate high potential for profitable response of rainfed upland rice production for Sudan Savanna to fertilizer N but little potential for other fertilizer nutrients. These results should, however, be considered together with other field research results in making fertilizer use decisions.

Simulating the Capacity of Rainfed Food Crop Species to Meet Social Demands in Sudanian Savanna Agro-Ecologies

“…This data helps to assess the plausibility of the simulated yields, given the scarcity of experimental studies on high-input rainfed rice, showing good agreement with the simulated yields of the most productive plots., Moreover, yields at fertilizer application rates of 100 kg N ha −1 are similar to those simulated with CERES at rates of 90 kg N ha −1 in the humid zone of Ghana [81]. Rice yield data at fertilization rates lower than 100 kg N ha −1 have been gathered from one single study [82] conducted in both upland and lowland fields (assumed to correspond to low fertility soils and hydromorphic soils, respectively) in the Sudanian zone of Burkina Faso and Mali. Yields in non-fertilized soils coincide with some of the observations reported in the literature [82,83].…”

“…Rice yield data at fertilization rates lower than 100 kg N ha −1 have been gathered from one single study [82] conducted in both upland and lowland fields (assumed to correspond to low fertility soils and hydromorphic soils, respectively) in the Sudanian zone of Burkina Faso and Mali. Yields in non-fertilized soils coincide with some of the observations reported in the literature [82,83].…”