Influence of residue management and simulated rainfall timings on pyroxasulfone efficacy and productivity of wheat in North West India.

The adoption of new advanced technology for finest one pass sowing solution in residue in North West India has resulted in increased interest among weed scientists to improve weed management strategies due to herbicide resistant Phalaris minor and herbicide efficacy. A study was conducted over two consecutive crop seasons at Punjab Agricultural University, Ludhiana and Krishi Vigyan Kendra, Muktsar, Punjab, India. The objectives of the study were to find out pyroxasulfone rate required as pre emergence (PRE) in residue removal and incorporation scenarios for weed control and to compare efficacy of PRE application under simulating rainfall at 2, 5 and 10 days after sowing (DAS) and its effect on wheat grain yield. Incorporation of paddy residue (RI) gave 3.8 & 3.7% and 1.8 & 5.1% higher grain yield than residue removal (RR) at Ludhiana and Muktsar during 2020–21 and 2021–22, respectively. At Ludhiana, pyroxasulfone 191.25 g ha⁻¹ recorded significantly less Phalaris minor than pyroxasulfone 127.5 ha^-1 but provided similar control of broad leaved weeds (Rumex dentatus and Medicago denticulata). However, both doses of pyroxasulfone recorded similar control of grass and broad-leaved weeds at Muktsar. Simulated rainfall increased the efficacy of pyroxasulfone and recorded less P. minor when given at 2 DAS than 10 DAS at Ludhiana but at Muktsar all simulated rainfall events did not affect weed density and biomass. Phyto-toxicity of pyroxasulfone was not observed on wheat crop when simulated rainfall was applied 2, 5 and 10 DAS in wheat sown under different residue scenarios at both the locations. • Paddy straw residue incorporation at 7 t ha⁻¹ gave 3.8 & 3.7% and 1.8 & 5.1% higher grain yield than straw removal (0 t ha⁻¹) at Ludhiana and Sri Muktsar Sahib during 2020–21 and 2021-22 seasons, respectively. • 13.7 and 21.1% higher grain yield was observed in 2020–21 than in 2021–22 at PAU, Ludhiana and Muktsar due to unconventional weather conditions during 2021–22. • Pyroxasulfone 191.25 g ha⁻¹ provided greater P. minor control than pyroxasulfone 127.5 ha⁻¹ at Ludhiana, but both doses were not significant to affect broad leaved weeds at Ludhiana Similarly, at Muktsar, no dose effect of pyroxasulfone was observed for both broadleaf and grass weeds. • Simulated rainfall increased the efficacy of the herbicide and provided greater P. minor control with 2 DAS than 10 DAS at Ludhiana but at Muktsar all simulated rainfall events produced non-significant effect on weed density and biomass. • Phyto-toxicity of pyroxasulfone was not observed on wheat crop when simulated rainfall was applied 2, 5 and 10 DAS under all residue treatments. [ABSTRACT FROM AUTHOR]