Possible Replacement of Wheat Post Herbicides with Soil Herbicide Pendimethalin

Abstract

The experiment was conducted between 2016-17 to evaluate the efficacy of PRE emergence and POST herbicides for effective weed control in wheat crops and analyse if pendimethalin may replace usually spring post-applied herbicides. The applied PRE emergence herbicide was pendimethalin and POST herbicides were prosulfuron, amidosulfuron + iodosulfuronmethyl- natrium + mefenpyr-diethyl, pyroxsulam, amidosulfuron + iodosulfuron-methylnatrium + mefenpyr-diethyl + fenoxaprop-p-ethyl. The weed population consisted mainly of annual and some perennial weeds. Weediness comprised 31 plants m-2 in the control plots and 1.3-9.0 plants m-2 in the plots treated with herbicides. The highest numbers of individuals were recorded for Persicaria maculosa (8.0 plants m-2), Chenopodium album (7.3 plants m-2), Apera spica-venti (7.0 plants m-2) and Convolvulus arvensis (3.0 plants m-2). Most POST herbicides effectively reduced dominant weeds with the highest efficacy in plots treated with herbicide amidosulfuron + iodosulfuron-metil-natrium + mefenpir-dietil (95.9%). Furthermore, the efficacy of PRE herbicide pendimethalin with two doses was lower compared to POST herbicides, besides amidosulfuron + iodosulfuron-metil-natrium + mefenpir-dietil + fenoxaprop-p-ethyl. The treated plots with herbicides showed a statistically higher wheat yield compared to control plots. The PRE herbicide pendimethalin may replace POST herbicides, but this depends strongly on used dosage, climatic conditions and weeds that germinate in the spring. Wheat yields differed among PRE herbicide pendimethalin applications and POST herbicide, ranging between 5115 and 7003 kg ha-1.