Biomass production, photosynthesis and quality of Panicum maximum under Leucaena leucocephala based silvopastroral system in semi arid tropics

Growth, biomass production, photosynthesis and quality attributes of Panicum maximum were studied underthe canopiesof seventeenyearold trees of Leucaena leucocephala underrainfed insemiarid tropicalenvironment. The full grown canopy of L. leucocephala at the spacing of 4x4 m allowed only 30–35% of total photosynthetic active radiation (PAR) which resulted reduction in under canopy temperature to 4.1°C. P. maximum produced 25.56 t/ha green and 7.37 t/ha dry biomass under the tree canopies of L. leucocephala. The dry matter yield reduced to 13.4% under the tree canopies over the open grown grasses. The decrease in biomass production under tree canopies may be due to reduction in leaf area index. P. maximum accumulated higher chlorophyll a and b under the shade of tree canopies indicating its shade adaptation potential. Rate of photosynthesis, transpiration and stomatal conductance decreased under the shading of tree canopies due to lower availability of PAR. Higher accumulation of crude protein, starch, sugar and nitrogen in leaves and stem of P. maximum indicates that this grass species also maintained its quality under L. leucocephala based silvopastoral system. The higher soil moisture, organic carbon content and available nutrients under L. leucocephala + P. maximum, maintained the sustainable growth and biomass production of the system for longer period. On the basis of overall growth performance, biomass production, chlorophyll accumulation and quality attributes, P. maximum is recommended for high shading environment of L. leucocephala in the silvopasture system under rainfed of semi-arid tropics.