Fertilizer Trial Results Of Maize And Maize-bean Intercrop Trials In Kenya

Fertilizer trial studies were conducted in all major crop producing agro-ecological zones (AEZs) of Kenya. The aim of the study was to establish reliable and current response curves for major food crops to applied nitrogen and phosphorus. The experimental sites of 0.5 ha were located in various AEZs. The experiment considered N and P205 at four levels each (0, 25, 50 and 75 kg/ha). Maize, Kenya's main food crop, was tested in pure stand and intercropped with beans. The study shows that intercropped beans affected maize yields differently in different environments. At 60 percent of the trial sites, intercropped maize yields were 5 to 47 percent less, while at 24 percent of the sites maize yields were 1 to 32 percent more, than sole crop maize yields. At 25 percent of the sites, gross monetary returns were less with intercropping. Maize response to N was widespread, especially in the western parts of Kenya and around Lake Victoria. P responses were few and rather localized, especially in the upper parts of Kisii, the Molo area and at Githunguri in Central Kenya. Crop response to applied nutrients was not found to relate well to characteristics of agro-ecological zones or to soil test levels. It was found to be feasible to predict the nitrogen and phosphorus intercrop needs from the maize sole crop response curves. Sets of equations are presented which enable the prediction of points on the intercrop response curves using the sole crop data
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