Nutrient uptake by wheat and Phalaris minor as influenced by weed management practices

A field experiment was conducted during Oct.-April 1998 and 1999 to evaluate the effect of time of sowing, cultivars, row spacing and weed control measure on the uptake of nutrients by P. minor and the availability of nutrients to the crop. Ear1y sowing (25^th Oct.), closer row spacing (15 cm) significantly decreased the nutrient removal by the P. minor compared with later sowing (10^th Nov. and 25^th Nov.) and wider row spacing (22.5 cm) respectively and thus resulted in higher nutrient uptake by the crop due to lesser dry matter production of P. minor. Uncontrolled weeds at harvest stage depleted on average 28.6, 4.2 and 44.4 kg N, P and K/ha. Isoproturon 0.94 kg/ha reduced the nutrient removal by the P. minor leading to increase in nutrient uptake by the crop.