Utilization efficiency of nitrogen, phosphorus and potassium as related to yield advantage in corn and mungbean intercrops

Growth, dry matter yield and uptake of N, P and K by intercropped corn and mungbean were better than when the component population in mixture were maintained at respective full sole crop populations i.e. 50,000 plants/ha of corn and 300,000 plants/ha of mungbean. Inoculation increased the leafiness of mungbean, and the uptake of nutrients by both the component crops which in turn increased the yield of dry matter. Nitrogen applied to corn at 60 and 90 kg/ha increased markedly leaf area index, crop growth rate and net assimilation rate and the uptake of N, P, and K by corn but decreased these traits in associated mungbean. The competition for nitrogen was evident in mungbean when it flowered at 33 DAS [days after sowing] but corn was not affected until two weeks later. Grain yield of corn was not affected by mungbean population in mixture but mungbean yield decreased as the population of either component was increased above the full sole crop population. Inoculation increased grain yield of both corn and mungbean. Mungbean yield decreased significantly above 30 kg/ha of applied N with corresponding increased in the yield of corn. Intercropping reduced the yield of mungbean by 35 % to 59%, corn was less affected. Lower population of either component increased the harvest index in intercropping compared to the sole crops. The yield advantage measured in terms of land equivalent ratio (LER) was higher at full sole crop population of either component crop. Inoculation improved the LER significantly by improving the partial LER of corn. The beneficial effect of applied N on increasing the partial LER of corn at higher levels was eroded by corresponding decrease in partial LER of mungbean. The highest LER of 1.40 was recorded at 30 kg N/ha. Corn attributed the major share in yield advantage but there was some indication that the magnitude of yield advantage was considerably affected by the yield of mungbean component