Poplar (Populus deltoides) Based Agroforestry Systems for an Alluvial Soil under Irrigated Condition in Western Uttar Pradesh

Poplar with high productivity in 6-12 years rotation is being preferred, particularly as boundary plantations, in various agroforestry systems in northern part of India. A quantitative approach is an important step in the quest for a better understanding of the complex mechanisms of tree-crop interaction, which should offer scientific basis for designing more productive and sustainable agroforestry systems. This paper reports on the quantitative estimations of various interactions occurring at the tree line/crop interface of Poplar and wheat grown on irrigated alluvial soil in Western U.P. No significant adverse effect was noticed on wheat crop when grown with association of 3 year old boundary plantation of Poplar. However, a significant decline of 15.5 per cent was recorded only up to a distance of 3 m from the tree base due to 4 year old plantation. Water use of the system increased upto 6 m from the tree line which caused moisture stress to the wheat crop. At the same time boundary plantation of Poplar had favourable effect on the micro-climate which improved the status of soil moisture between 6-9 m distance and increased the water use efficiency. Competition for natural resources was reduced between weeds and wheat due to reduction in weed population and biomass in the system. Litter production averaged 1103 kg ha^-1 in 3 and 4 year old plantation and this returned 12,2.5,8,21.3 and 8.6 kg ha^-1 ofN, P, K, Ca and Mg to the soil. Addition of leaflitter near the tree line tended to change the physico-chemical properties of the soil.