Evaluation of crop arrangement and phosphorus rate on performance of maize-common bean intercropping in western Kenya

The effect of phosphorus (P) rate and crop arrangement on the performance of component crops in maize-bean intercropping systems was investigated at two sites; Malanga and Bugeng’i in western Kenya. A split plot design with five crop arrangements in the main plots i.e., one row of maize alternating with one row of beans (conventional), maize and beans planted in the same hole, two rows of maize alternating with two of beans (Mbili), sole maize and sole beans, in a factorial combination with three P rates; 0, 30, and 60 kg ha-1 in the subplots, was used. Bean yields were low (< 1 t ha-1) but they increased with increasing P rate at both sites. Response of maize to P fertilizer was however poor at Malanga mainly due to Striga weed infestation. Yields of beans did not significantly differ among crop arrangements at both sites. At Bungeng’i, there was a significant interaction between P rate and crop arrangement. At this site, the maize yield in the conventional arrangement increased with increasing P rate but for the Mbili arrangement, the grain yield from application of 30 kg P ha-1 was significantly higher than that at 0 kg P ha-1 and similar to that 60 kg P ha-1. Therefore, it is not beneficial to fertilize beyond 30 kg P ha-1 at this site with the Mbili arrangement. Intercropping was beneficial in all crop arrangements (Land equivalent ratio >1) and can therefore be practiced, except for maize and beans planted in the same hole with no P application at Bugeng’i