Journal of Research

Field investigation was conducted on a sandy loam soil at Punjab Agricultural University, Ludhiana during rabi seasons of 1999–00 and 2000–01 to study nutrient uptake in wheat-Phalaris minor ecosystem in relation to seed rate, row spacing and herbicides. Crop raised with 150 kg ha⁻¹ seed rate increased grain yield of wheat by 12.3% over recommended seed rate (100 kg ha⁻¹). The crop raised at closer spacing of 15 cm reduced the dry matter accumulation of P. minor by 32.3 per cent leading to increase in grain yield of wheat by 10.5% compared to that at 22.5 cm. Post-emergence application of clodinafop 0.06 kg ha⁻¹ gave selective control of resistant P. minor and increased wheat grain yield by 128.9% over isoproturon 0.94 kg ha⁻¹. The crop raised with higher seed rate of 150 kg ha⁻¹ and at closer row spacing of 15 cm recorded significantly higher uptake of N, P and K, while the nutrient depletion by the P. minor decreased considerably compared to the crop raised with recommended seed rate of 100 kg ha⁻¹ and row spacing of 22.5 cm, respectively. The depletion of N, P and K by P. minor in isoproturon 0.94 kg ha⁻¹ treated plots was significantly higher compared to clodinafop 0.06 kg ha⁻¹. Post-em. application of clodinafop 0.06 kg ha⁻¹ reduced the nutrient removal by P. minor appreciably, leading to their increased utilization by the crop.