Weed dynamics, nutrient uptake and crop productivity in wheat under organic, inorganic and integrated nutrient management practices after twenty-six years of experimentation

A long-term field experiment initiated in 1995 at Research Farm of Chaudhary Charan Singh Haryana Agricultural University (CCSHAU), Hisar, India, was selected for research experiment during rabi season of 2021–22 with treatments: recommended dose of nitrogen (N) (150 kg/ha) and phosphorus pentoxide (P2O5) (60 kg/ha); farmyard manure (FYM) at 15 t/ha alone and in combination with N (150 kg/ha) and P2O5 (30 kg/ha); poultry manure at 5 t/ha alone and in combination with N (150 kg/ha) and P2O5 (30 kg/ha); press mud at 7.5 t/ha alone and in combination with N (150 kg/ha) and P2O5 (30 kg/ha) in main plot and weed management: pendimethalin at 1.5 kg/ha as pre-emergence alone and its sequential application with clodinafop + metsulfuron methyl (ready mix) at 64 g/ha as post-emergence; weedy check and weed-free in sub-plot with 3 replications in a split-plot design. Application of FYM at 15 t/ha + N (150 kg/ha) and P2O5 (30 kg/ha) produced a grain yield of 5341 kg/ha, representing a significant 17.4 % increase over the recommended dose of N (150 kg/ha) and P2O5 (60 kg/ha) with lowest weed density of Anagallis arvensis and Melilotus indica. Conversely, the highest weed density of Coronopus didymus, Rumex dentatus and Phalaris minor was observed under press mud at 7.5 t/ha + N (150 kg/ha) and P2O5 (30 kg/ha). Furthermore, the sequential application of pendimethalin at 1.5 kg/ha followed by clodinafop + metsulfuron methyl (ready mix) at 64 g/ha significantly increased yield and resulted in the lowest weed density. Under weedy check conditions, weeds removed 10.71, 5.87 and 73.22 kg/ha of N, phosphorus (P) and potassium (K) respectively reducing grain yield by 34.5 % compared to weed free conditions.