EFFICIENT WEED MANAGEMENT OF WHEAT UNDER CONSERVATION AGRICULTURE SYSTEMS WITH THE BEST POST-EMERGENCE HERBICIDE AND AT THE RIGHT APPLICATION RATE

Abstract

Planting wheat in a strip-tilled field is a challenge for controlling weeds at the early crop growth stage and ultimately yield has to sacrifice. Therefore, a study was done to select suitable herbicides and their appropriate application rate for getting effective weed control and optimum yield of strip-planted wheat under the conservation agriculture (CA) system. A two-year study (July 2017 to March 2019) was done that started with untreated non-puddled transplanted rainy season rice (following general weed management by applying pyrazosulfuron-ethyl: 10 g a.i ha−1 as pre-emergence control and bispyribac-sodium: 20 g a.i ha−1 as post-emergence control) and ended with strip-planted wheat. Rice was harvested retaining 20 cm standing residue and the subsequently planted wheat crop received post-emergence (POST) herbicides as treatments. Three POST herbicides named ethoxysulfuron (Sunrise; early post-emergence: 150 g a.i ha−1), carfentrazone-ethyl plus isoproturon (Affinity; late post-emergence: 50.75 g a.i ha−1) and carfentrazone-ethyl (Hammar; late post-emergence: 24 ml a.i ha−1) were applied at their label rate and double of the label rate and compared with a non-treated control (manually weeded at 20 and 40 days after wheat sowing). Pendimethalin was commonly applied in wheat to control pre-emergence weeds. The study identified 17 weed species in the strip-planted wheat field during 2017-18 and 09 species during 2018-19. Application of carfentrazone-ethyl plus isoproturon both at the label rate and double of the label rate controlled all weeds most effectively; however, the study suggests label rate application of carfentrazone-ethyl plus isoproturon in strip-planted wheat for attaining optimum yield and economic profit.