Influence of pre and post emergence herbicide application on weed growth and nutrient removal in wheat (Triticum aestivum L.)

Two years field experiment was conducted during rabi seasons of 2015-16 and 2016-17 at Instructional Farm (Agronomy), Rajasthan College of Agriculture, MPUAT, Udaipur. The experiment comprised of fifteen treatments viz. pendimethalin 0.75 kg ha-1; sulfosulfuron 0.025 kg ha-1; metribuzin 0.21 kg ha-1; clodinafop 0.06 kg ha-1; metsulfuron 0.004 kg ha-1; pendimethalin + metribuzin 0.75 + 0.175 kg ha-1; pendimethalin fb sulfosulfuron 0.75 + 0.02 kg ha-1; pendimethalin fb clodinafop 0.75 + 0.05 kg ha-1; pendimethalin fb metsulfuron 0.75 + 0.004 kg ha-1; metsulfuron + sulfosulfuron 0.003 + 0.02 kg ha-1; pinoxaden + metsulfuron 0.06 + 0.004 kg ha-1; mesosulfuron + iodosulfuron 0.012 + 0.0024 kg ha-1; clodinafop + metsulfuron 0.06 + 0.004 g ha-1, two hand weeding at 30 & 45 DAS and unweeded control, replicated four times in Randomized Block Design. Wheat variety Raj.- 3765 was used as a test crop. All weed control treatments appreciably reduced density and dry matter of monocot and dicot weeds. Among herbicides, application of tank mixed metsulfuron + sulfosulfuron mixture provided maximum per cent reduction in density and dry matter (90.05 & 95.35%) of total weeds over unweeded control followed by mesosulfuron + iodosulfuron, clodinofop + metsulfuron and pinoxaden + metsulfuron (88.8, 88.0 and 87.4 & 94.7, 94.4 and 94.2%) at 60 DAS which resulted into highest weed control efficiency (95.4, 94.7, 94.4 and 94.2%) and proved significantly superior over rest of the herbicidal treatments. However, variations were at par with two hand weedings. The minimum NPK content 2.52, 0.41 and 1.24 per cent, respectively were recorded with weed control through metsulfuron + sulfosulfuron.