Variations in the Light Interception and Associated Physiological Traits of Cowpea and Fodder Sorghum Grown under Different Agroforestry Systems

Abstract

Light interception is major factor for characterizing the resource capture and use efficiency of cropping systems under intercrops. Agroforestry system is land use practices that combine agricultural crops and trees in different ways and has shown to benefits agriculture and forestry. The choice crop in agroforestry depends on light availability penetrated through trees which would alter the physiological processes in turn to yield. The experiment was conducted out with cowpea followed by fodder sorghum as intercrops under four agroforestry systems viz., Khaya senegalenesis, Melia dubia, Dalbergia sissoo and Casuarina equisetifolia and measured the light interception, gas exchange parameters and yield traits. Light interception ratio of cowpea under Dalbergia sissoo were observed maximum with 76 % and minimum of 58 % in Khaya senegalenesis @ 60 days after sowing. In case of gas exchange parameters, photosynthetic rate and stomatal conductance of cowpea and fodder sorghum were found significantly higher under Dalbergia sissoo compared to other agroforestry systems. The yield traits for cowpea and fodder sorghum were recorded higher in open space followed by Dalbergia sissoo while lower yield was noticed in cowpea under Khaya senegalenesis and Casuarina equisetifolia in case of fodder sorghum. The yield reductions in cowpea and fodder sorghum under Dalbergia sissoo were 19 % and 31% compared to open conditions indicating the differential response of C3 and C4 crops towards intercepted light. Microclimatic variables mainly altered due to influence of canopy structure that was reflected in reduction in temperature especially under Khaya senegalenesis. In conclusion, cowpea was found to be better intercrop mainly under Melia dubia based on gas exchange and yield parameters.