Abstract

Effects of phosphorus rate and crop arrangement on yields and economic benefits in maize-bean cropping systems were investigated for two seasons: Short rains (SR) of 2015 and long rains (LR) of 2016 in Western Kenya. A split plot design with five crop arrangements in the main plots; one row of maize and beans alternating (conventional), maize and beans planted in the same hole (SH), two rows of maize alternating with two of beans (Mbili), sole maize and sole beans, and three P rates; 0, 30, and 60 kg ha-1 in the subplots was used. There were no significant effects of crop arrangement on maize and bean yields in LR but bean yields increased with increasing P rate in both seasons. Within a crop arrangement, maize yields also increased with P rate in the SR. Conventional and Mbili arrangements had similar yields for both beans and maize which were superior to SH at 60 kg P ha-1 in SR. Sole beans significantly out-yielded intercropped ones. Intercropping was only beneficial (LER > 1) with adequate rainfall in SR but financial returns were too low for all the tested practices because of low yields coupled with high production costs and low producer prices.

Key words: Crop arrangements, intercropping efficiency, phosphorus.