Agro-techniques for increasing productivity of wheat (Triticum oestivum) under poplar (Populus deltoides) plantation

Abstract

Field experiments were done to standardize the agronomic practices of wheat grown in association with poplar ( Populus deltoides Bartr.) plantation at Ludhiana, Punjab. The study was conducted under block plantation of pop- lar (Clone G-48) grown at a spacing of 5 x 4 m, (accommodating 500 trees/ha) at the age of 2, 3 and 4 years in 2004, 2005 and 2006, respectively. The soil of the site was low in available N and medium in available P. Three seed rates (100, 125 and 150 kg/ha) and combinations of 3 N (125, 187.5 and 250 kg N/ha) and 2 P levels (27 and 40.5 kg P/ha) were evaluated to find out the optimum fertilizer and seed requirement of wheat (cv. PBW 343) inter- cropped with poplar. The height and diameter of trees increased from 10.4-15.1 m and 10.4 - 16.5 cm, respectively in the span of 2 years (2004-06). Wheat yield under poplar reduced with the increase in tree age. However, the crop under poplar responded positively to higher fertilizer and seed rates. The yield of sole wheat was significantly higher when compared with intercropped wheat. Among 3 seed rates, 25% additional seed rate (125 kg/ha) over recommended to sole wheat significantly increased (6%) the grain yield of wheat under poplar plantation. Among different fertilizer levels, grain yield of wheat was significantly higher (3.93 tonne/ha) at 50% additional N than rec- ommended to sole wheat with recommended P i.e. at 187.5 kg N and 27 kg P/ha. N and P uptake by wheat was higher in sole wheat than under poplar. Additional application of seed and nutrients over the recommended levels significantly increased their uptake. The benefit cost ratio in poplar plantation were highest with the application of 150 kg/ha seed and 187.5 + 27 kg N + P/ha to wheat.