Efficacy of Tank Mix Application of Sulfonylurea Herbicides Against Broadleaf Weeds in Wheat and their Residual Effects on Succeeding Crop of Sorghum under Zero Tillage

摘要

A field experiment was conducted during 2004-05 and 2005-06 at Agronomy Research Farm of Chaudhary Charan Singh Haryana Agricultural University, Hisar to evaluate different sulfonylurea herbicides applied as tank mixture against weeds in wheat and their carry-over effects on succeeding crop of sorghum grown for fodder. All the herbicidal treatments resulted in significant reduction in plant population of different broadleaf weeds compared to weedy check. Density of individual weeds was also reduced with the corresponding increase in the dose of herbicides in the tank mixture; however, control of Cirsium arvense was comparatively less than other broad leaf weeds. Sulfosulfuron+metsulfuron 15+4 g/ha, sulfosulfuron+triasulfuron 15+30 and 15+40 g/ha. and metsulfuron+triasulfuron 3+30 g/ha proved better against all weeds and on an average of two years, they reduced the dry weight of total weeds to the extent of 87 to 96%. Consequently, these four treatments produced effective tillers and grain yield ofwheat more than all other herbicidal treatments and were statistically at par to weed free check during both the years. Weeds allowed to grow throughout the crop season reduced the grain yield of wheat to an extent of 40-42% during two years of study. The residual effects of only sulfosulfuron+chlorsulfuron 15+20 g/ ha, sulfosulfuron+metsulfuron 15+4 g/ha, sulfosulfuron+triasulfuron 15+40 g/ha and metsulfuron+triasulfuron 3+30 g/ha on succeeding crop of forage sorghum were noticed in terms of reduced plant height (45 DAS), fresh weight (kg/m~2) at 45 DAS and fodder yield of sorghum (75 DAS) only under the situation where field was prepared by giving One harrowing fb one pass of one cultivator and planking before sowing of sorghum (i. e. after wheat harvest). But such residual toxicity on sorghum was not observed due to any herbicidal treatment in the plots where sorghum was sown under unprepared (no-tillage) condition after wheat harvest during both the years.