14. Utilization efficiency of applied nitrogen as related to yield advantage in maize/mungbean intercropping.
Field Crop Research, 30, 1992, pp. 41-51
This study was undertaken to examine the effects of rhizobial inoculation and applied nitrogen on growth and performance of intercropped maize (Zea mays L.) and mungbean [(Vigna radiata(L.)
The experiment was conducted to determine the effects of rhizobial inoculation and nitrogen applied at 0, 30, 60 and 90 kg ha-1 on growth and performance of intercropped maize and mungbean.
Inoculation decreased both dry matter and grain yield of intercropped maize and mungbean. Applied N at levels above 30 kg ha-1 increased the dry matter and the grain yield of maize but reduced that of the associated mungbean. Intercropping drastically reduced the dry matter yield of mungbean but maize showed negligible reductions;the reductions were evident when the crops flowered. Inoculation increased the land equivalent ratio (LER) by increasing the partial LER of maize. Applied N at high levels also increased the partial LER of maize but this failed to increase LER due to corresponding reductions in partial LER of mungbean. Nitrogen at 30 kg ha-1 produced the highest LER (1.40).
Applied N increased N uptake of maize but decreased that of mungbean.
Inoculation increased the N uptake of both mungbean and maize at 48 days and onward. Large reduction in N uptake of intercropped mungbean was observed when it flowered at 33 days but maize was affected 2 weeks later at the tasseling stage. Thus, the competition for N was acute when the crops were at the reproductive stage.
The LER analysis in terms of N utilization efficiency showed that N absorption efficiency of both maize and mungbean was reduced due to intercropping, and mungbean was more affected than maize.
Intercropping severely depressed N uptake in mungbean compared to maize but mungbean utilized the absorbed N relatively more efficiently than maize producing a higher quantity of grains per unit of absorbed N compared to sole mungbean.
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Africa, Ethiopia, study, greenhouse trials, underseed cropping, legumes, wheat, soil erosion
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