Effect of increased intimacy between maize and beans in an intercrop system on growth and yield of maize under varying nitrogen levels.

Abstract

Field Nairobi's experiments Faculty of increasing were conducted at the University Agriculture farm to investigate of the merits plants of the proximity between maize and bean in an intercrop system and how N-fertilizer levels influence this interspecific interaction. Four planting patterns and four nitrogen levels were tested in a factorial experiment and laid out in a completely randomised block design with three replicates. The planting patterns consisled of sole maize, maize and beans intercropped in alternate rows, maize and beans intercropped as alternating plants in the same row and maize and beans intercropped in the same hi I I. The N levels were 0, 50, 100 and 150 Kg N/ha. Maize variety Embu 512 and bean variety GLP-2 were used. Plants were sampled biweekly during the growing season to determine dry matter weight and leaf area. At the end of the vegetative cycle, yield and yield components were also measured. Results and at 19 showed that at 15 and 19 WAE in the first season WAE in the second season, maize intercropped with beans in alternate rows had statistically inferior dry matter compared to maize sown in the rest of the patterns, whose dry matter plants yields were statistically similar. Dry matter of maize significantly increased with N application at sampling times. Dry matter of bean plants patterns, was all not significantly affected by the planting but N application significantly increased this parameter. Planting patterns had no significant effect on Leaf area indices of both maize and bean plants, but this parameter was significantly increased with N application in maize plants. Planting patterns and nitrogen application had a significant effect on maize grain yield in bolh spasons. The interaction between the planting patterns and N levels was significant in the first season. At 0 and 50 Kg N/ha, maize intercropped with beans in the same hole significantly outyielded maize sown in the rest of the patterns; whereas sole maize and maize intercropped with beans in the same row, whose yields were statistically similar, gave significantly higher grain yield than maize intercropped with beans in alternate rows. At 100 and 150 Kg N/ha, sole maize had grain yield that was non-significantly higher than those of maize intercropped with beans in the same row or same hole, but statistically higher than that of maize intercropped with beans in alternate rows. In the second season, a tal I N Ieve 1s, there were no significant differences among the planting patterns except at o and 50 Kg N/ha where maize intercropped with beans in the same hole significantly out-performed maize intercropped with beans in alternate rows. Maize intercropped with beans in the same hole did not significantly respond to application of more than 50 Kg N/ha whereas maize sown in the rest of the patterns did not significantly respond to application of above 100 Kg N/ha. Both planting patterns and N levels had a significant effect on the number of kernels per cob-row, lOO-kernel weight and cob-length, but had no effect on the number of rows per cob. Planting patterns had no significant effect on bean yields, but N application significantly increased this parameter. Based on these results, it was concluded that increased intimacy between maize and bean plants in an intercrop system increased maize yields only under low N levels.