Long-term Effects of Integrated Nutrient and Weed Management on Weed Population Dynamics and Nutrient Uptake in Semi-arid Wheat Production

Abstract

A field experiment was conducted at Research Farm of the Department of Soil Science, CCS Haryana Agricultural University, Hisar, Haryana, India, to evaluate the long-term effects of nutrient management and weed management practices on the population dynamics of major weed species in wheat. Experiment was laid out in a split-plot design, comprising seven nutrient management treatments viz. NP: Recommended doses of nitrogen (150 kg/ha) and phosphorus (60 kg/ha); FYM: Farmyard manure at 15 t/ha; FYM+NP: FYM at 15 t/ha combined with N (150 kg/ha) and P (30 kg/ha); PM: Poultry manure at 5 t/ha; PM+NP: Poultry manure at 5 t/ha with N (150 kg/ha) and P (30 kg/ha); PMUD: Press mud at 7.5 t/ha; and PMUD+NP: Press mud at 7.5 t/ha combined with N (150 kg/ha) and P (30 kg/ha) in the main plots and four weed control treatments viz. PRE: Pendimethalin at 1.5 kg/ha applied pre-emergence; PRM: Pendimethalin at 1.5 kg/ha PRE followed by clodinafop + metsulfuron-methyl at 64 g/ha as a post-emergence (RM) application; weedy check; weed-free check in the subplots, each replicated three times. Among nutrient treatments, FYM+NP consistently recorded the lowest densities of Anagallis arvensis (2.94–3.23 plants/m²) and Melilotus indica (3.11–3.40 plants/m²), while, PM treatment markedly reduced Coronopus didymus, Rumex dentatus and Phalaris minor with minimum densities ranging from 3.26-4.64, 2.52-3.49 and 1.962.66 plants/m2, respectively. Total weed dry matter remained comparatively higher under PMUD+NP, with values of 2.98, 6.21, 8.48 and 10.05 g/m² at 30, 60, 90 and 120 DAS, respectively. FYM+NP resulted in the highest nutrient uptake by weeds (0.21% N, 0.111% P and 1.45% K), indicating enhanced nutrient availability. Among weed management treatments, PRE and PRM significantly reduced the densities of all major weed species compared to the weedy check. At 30 DAS, minimum weed populations were recorded under PRE, whereas, PRM was more effective during later stages of crop growth in herbicides treatment. Weed dry matter was highest under PRM at 30 DAS, while, higher at 60–120 DAS under PRE.