Penoxsulam influence on weed complex and productivity of transplanted rice and its residual effects in rice-wheat cropping system

Abstract

Field experiments were conducted to evaluate the bio-efficacy of penoxsulam 2.67% w/w (2.5% w/v) OD applied as post-emergence (PoE) in transplanted rice and its residual effect in succeeding wheat crop at CCS Haryana Agricultural University, Regional Research Station, Karnal. Penoxsulam 22.5 g/ha reduced the density (0.0 to 0.7/m2) and dry weight (0.0 to 6.3 g/m2) of grassy weeds during 2011 and 2012 and was similar to weed free check. Penoxsulam at 22.5 g/ha resulted in similar dry weight of grassy and broad-leaf weeds with all other herbicidal treatments, and was superior to bispyribac-sodium 20 g/ha in controlling grassy weeds during 2012 and bispyribac-sodium 20–25 g/ha in controlling broad-leaf weeds during both the years. It provided almost complete control of sedges. The grain yield under penoxsulam 22.5 g/ha (5.68 t/ha in 2011 and 6.89 t/ha in 2012) was at par with its higher dose (25 g/ha) and more than its lower dose (20 g/ha). It also resulted in net returns (’ 31921–55372/ha) and B:C ratio (2.03–2.68) almost similar/higher to recommended post-emergence herbicides. Weeds growing throughout the crop season reduced the grain yield of rice to the tune of 37.5 and 43.4% during 2011 and 2012, respectively. Penoxsulam 22.5 g/ha also performed well against weed complex in adaptive trials at farmers’ fields during Kharif 2017. There was no phyto-toxicity of penoxsulam even up to 50 g/ha on transplanted rice crop and also there was no residual phyto-toxicity on the succeeding wheat during 2011–12 to 2013–14. It also did not leave any detectable residual carry-over at harvest in soil, straw and rice grain when applied up to 45 g/ha.