Performance of Leucaena, sorghum or cowpea and resource sharing in an agrisilviculture system in semi-arid India.

摘要

In an agrisilviculture system, trees and crops compete for above and below ground resources. This study aimed at quantifying the effect of shoot pruning and root barriers around pollarded trees on the production of crop and tree components with and without application of fertilizer to the crop. Sorghum (1991 & 1992) and cowpea (1993 & 1994) were grown as intercrops with Leucaena trees on a shallow red soil (alfisol) under rainfed conditions at Hyderabad, India.;Impact of root barriers was not significant on either crop. The study suggested that competition for light was stronger than for soil water. Straw and grain yield of sorghum, and dry matter yield of cowpea were found to be roughly proportional to the amount of light intercepted by the crop at harvest.;Pruning of trees twice during the cropping season reduced tree diameter growth and branch and foliage yield compared to no pruning. Unpruned trees yielded 5643 kg ha;The study highlighted the competitive interaction between trees and crops. The agrisilvi-system produced about 50% more biomass with unpruned trees than with pure crop or pure tree. Based on cash value (fodder yield equivalent) it would require 1.55 times as much land if trees and crops were grown separately compared to agrisilvi-system with unpruned trees. Soil nitrogen economy and stability of fodder and fuelwood production can be achieved with pollarded-unpruned leucaena trees in an agrisilvi-system but grain crop yields are severely depressed. Thus, there was little advantage of the agrisilvi-system over pure cropping for meeting the present and increasing demand of food production. For this agrisilvi-system to be adopted by subsistence farmers in India further refinements must be developed so that crop yields are maintained.;Crops grown with pruned trees had higher leaf area index and dry matter than did those with unpruned trees. The grain yield of sorghum was 76% and 39% of the pure crop yield (1553 kg ha