Optimizing Seed Rate and Herbicide Doses With or Without Adjuvant for Weed Control and Its Influence on Yield of Winter Wheat

A field trial was conducted to evaluate the interactive effect of seed rates and herbicides in combination with adjuvants on weed dynamics and wheat yield. This study was comprised of 3 seed rates; 100 kg h -1 (S1), 130 kg h -1 (S2), 160 kg h -1 (S3), and 3 herbicide dosages (100% recommended dose of Mesosulfuron-methyl + Iodosulfuron-methyl-sodium (H1), 75% of the dose (H2), and 75% dose + adjuvant (H3). The results revealed that average weed density, fresh weight, and dry weight were lower in seed rate 160 kg h -1 by 33.37%, 31.52%, and 28.78% compared to 100 kg h -1 before herbicide application, respectively. After 30 days of herbicide application, weed density, fresh weight, and dry weight were 42.16%, 34.74%, and 40.91% less in treatment with the combination of S3H3 compared with S1H2. Yield and yield parameters were significantly affected by the different seed rates and herbicide dosages. 1000-grain weight, spikelets, and grains/spike were greater in the lower seed rate (100 kg h -1 ) with H3, while the grain yield, biological yield, and harvest index were 26.05%, 21.81%, and 5.39% higher in the treatment S3H3 as compared with S1H2. To achieve optimal grain yield, a seed rate of 160 kg h -1 is recommended, along with 75% of the recommended herbicide dose with adjuvant.