Efficiency Of Intercropping Research Articles

Comparison of nitrogen, phosphorus and potassium utilization efficiency in maize/mungbean intercropping

SUMMARYEffects of rhizobial inoculation and applied nitrogen on the utilization efficiency of N, P and K were studied in relation to the yield advantage in additive maize/mungbean intercrops at Los Baños, Philippines in 1988. Inoculation increased grain yield of both maize (Zea mays L.) and mungbean (Vigna radiata (L.) Wilczek). Yield of maize increased by 60% in the sole crop and 71% in the intercrop as the N application rate was increased from 0 to 90 kg/ha, with a corresponding decrease of 29–35% in the yield of the associated mungbean. Intercropping reduced mungbean yield by 35–57%; maize was less affected. Inoculation also improved the land equivalent ratio (LER). The highest LER (1·49) was obtained at 30 kg N/ha with inoculation.Nutrient absorption by both maize and mungbean was reduced due to intercropping, mungbean being more affected than maize. The reductions in the N absorption efficiency of maize ranged from 4 to 37% and those of mungbean from 37 to 58%. Increases in N rate increased N absorption of maize but caused greater reductions in N absorption of mungbean. Reductions in P absorption by intercropped maize declined with increases in applied N and with inoculation. Inoculation, however, had a lesser effect on K absorption efficiency.Land equivalent ratio analysis in terms of N, P and K utilization efficiency showed that the increase in LER over unity was due largely to a higher total uptake of nutrients by the component crops in the mixture than by the sole crops. The greater efficiency of intercrops than of the sole crops in converting absorbed nutrients to grains also contributed to the yield advantage.

The combined effects of nitrogen fertilizer and density of the legume component on production efficiency in a maize/cowpea intercrop system

The combined effects of applied nitrogen and of legume density on the yields and efficiency of cereal/legume intercropping were examined, using maize and cowpea. The levels of applied nitrogen were 0, 30, 60 and 120 kg N ha −1, and intercrop cowpea densities were 80 000, 100 000, 120 000 and 150 000 plants ha −1. The interaction of applied N and density of companion cowpea on yield of maize was negative. In maize, the yield losses due to intercropping were alleviated to some degree by N application, but in cowpea they were accentuated, and it appeared that maize was more competitive than cowpea. Maize was more efficient than cowpea in the utilization of N to produce grain; with each increment of N, efficiency declined in maize but was almost constant in cowpea. The Land Equivalent Ratio (LER), a measure of the efficiency of intercropping, declined with increasing levels of applied N but did not change significantly when intercrop cowpea density exceeded 100 000 plants ha −1. The LER values followed trends in cowpea rather than maize yields, and this may be attributed to shading of cowpea by maize.

Evaluation and Presentation of Intercropping Advantages

SUMMARYIt is proposed that two distinct objectives should be recognized in the evaluation of intercropping advantages: (i) a biological objective to determine the increased biological efficiency of intercropping and (ii) a practical objective to determine the advantages that are likely to be obtained by a farmer. The sole crop systems with which intercropping must be compared to satisfy these objectives are defined. Evaluation in relative, absolute, monetary and nutritional units is discussed and some aspects of presenting intercropping data in graphical form are illustrated.