Abstract
An experiment was conducted to determine the effects of component populations on the performance of maize-mungbean intercropping and to relate N utilization efficiency to the yield advantage. The dry matter yields of maize and mungbean in the mixtures studied and the land equivalent ratio (LER) were at a maximum when the component crops were at their respective sole crop populations of 50 x 103 and 300 x 103 plants ha-1, respectively. Component populations of mungbean did not have a significant effect on the grain yield of maize but mungbean yield decreased as the population of either component crop was increased. Nitrogen absorption by both maize and mungbean was lower in intercropping compared with that in the sole crops; the proportional reduction in N absorption efficiency of maize ranged from 0.28 to 0.37 and that of mungbean from 0.50 to 0.57. Increasing the maize population caused a reduction in the N absorption efficiency of mungbean although it increased the N absorption efficiency of maize. The N absorption efficiency of maize and mungbean intercropped in all combinations of populations was higher than that of the sole crops added together. This was the major source of the increase in LER over unity. The N conversion efficiency, measured as the unit of grains produced unit-1 of N absorbed, decreased in intercropped maize but increased slightly in mungbean. However, in contrast to the absorption efficiency of nitrogen, the contribution of the overall conversion efficiency towards increasing the LER over unity was negative.
