The Efficiency of Integrated Pre-Emergence and Post-Emergence Herbicides in Nutrient Uptake by Wheat and Nutrient Depletion by Weeds in Sesame-Wheat Cropping System in Khuzestan

In order to investigate the effect of pre-emergence and post-emergence herbicides on nutrient depletion, weed population and nutrient uptake by wheat in sesame-wheat cropping system in Khuzestan a field experiment was conducted in randomized complete block design with three replications in the research farm of Shahid Chamran University of Ahvaz in 2019-2020. Treatments included no weeding, hand weeding, Pendimethalin+Atlantis, Pendimethalin+Metribosin, Trifluralin+Atlantis, Trifluralin+Metribozin, Pendimethalin+2,4-D, Trifluralin+2,4-D, green mungbean+2,4-D and 2,4-D in plots seeded by wheat cv. ‘Mehregan’. Weed population varied notably among the experimental treatments. At 60 days after sowing, while the mean number of weeds was 5.6 plants per m-2, it was significantly different among the weed control treatments. Moreover in this growth stage, Pendimethalin+Atlantis and Pendimethalin+Metribuzin treatments significantly reduced the weed population compared to the control no weeding condition. Generally, hand weeding and Pendimethalin+Atlantis treatments improved the growth and yield of wheat compared to Trifluralin+Atlantis, Trifluralin+Metribosin, and Trifluralin+2,4-D treatments, due apparently to reducing weed interference and increasing the uptake of nitrogen, phosphorus and potassium of the wheat plants. We concluded that the pre-emergence application of Pendimethalin herbicide along with post-emergence application of Metribozin and Atlantis herbicides at the seedling stage of wheat may increase the absorption of nutrients and grain yield.