Effect of inoculation and varying bean densities on biomass and yield of inter cropped maize and beans

Abstract

Nitrogen is often the most essential nutrient for maize production, particularly with respect to biomass accumulation, leaf area index and grain yield. However, commercial fertilizers as a source of nitrogen, are becoming increasingly expensive and out of reach of most small scale farmers in the developing countries. To obtain a cheaper alternative source of nitrogen, field experiments were conducted at the University of Nairobi's Faculty of Agriculture farm to investigate the effect of rhizohial inoculation of beans on ,j , growth and yield of maize and beans at various bean densities inter-cropped with maize in the same hill and to examine the inter action between inoculation and density of beans inter cropped with maize in same hill. Two inoculation levels and four bean densities were tested in a factorial experiment .- laid out in a completely randornised block design with three replicates. The inoculation consisted of non-inoculated and inoculated treatments of beans. The varying bean densities were: One bean plant per hill, two bean plants per hill, three bean plant and four bean plants per hill. Each planting hill also carried one maize plant. Maize variety, Embu (Hs12) and bean variety GLP-2 were used, Both bean and maize plants were sampled during the growing season to determine the dry matter yield as well as the nodule number on the bean plants. At the end of the growing cycle, yield and yield components were measured. Soil samples were collected from the hills to determine the percent soil nitrogen in the hills at maize flowering (12 WABE), maize maturity (24 WABE) and one month after maize harvest (28 WABE). xiii In almost all parameters.results showed that the inoculated treatments were statistically not different from the non inoculated treatments. Bean grain yield increased with increasing bean density while maize yield decreased with increasing bean density. Yield components per plant of both maize and beans decreased with increasing bean density. The increasing bean density did not significantly affect the percent soil nitrogen at all stages of soil sampling . The interaction between inoculation and bean density treatments was not significant.