Efficacy of S-Metolachlor and Acetochlor on Weed Control in Sweet Corn

Abstract

Weeds are a major problem in sweet corn production systems. This is because weeds compete for various growth factors. Affecting the yield of sweet corn decreased. Farmers in Sukhothai province make use of the use of paraquat and atrazine as herbicides for weed control. However, because to the ban on paraquat since 1 June 2020, it is necessary to recommend alternate herbicides instead. The objective of this study was to examine the effectiveness of pre-emergence herbicides, specifically s-metolachlor and acetochlor, in managing weed growth in sweet corn. The experiment site was done at Srisumrong district, Sukhothai province during March 2020 - February 2021 (spray paraquat in the trial plot before 1 June 2020) The Randomized Block Complete Design (RBCD) consisted of 11 treatments and 5 replications. The treatments included a weedy check, hoeing, and the farmer practice of using atrazine followed by paraquat. Additionally, acetolchlor was applied at either 340 and 538 grams of active ingredient per Rai, either 1 and 7 days after planting (DAP). s-metolachlor was also applied at either 255 and 340 grams of active ingredient per Rai, either 1 and 7 DAP. The major weeds found in this area were Echinochloa colona, Digitaria cilliaris and Cyperus rotundus. Both the rates of s-metolachlor and the different days of use demonstrated greater weed control efficiency compared to both rates of acetochlor and the farmer's usual practice. The weed number and dry weight of the s-metolachlor treatments significantly exhibited a decrease compared to the other treatments. The results of the sweet corn yield analysis indicate that the s-metolachlor treatments exhibited outstanding ear number and fresh yield compared to the acetochlor treatments and farmer practice. However, there was no significant difference observed when compared to the hoeing method. Soil samples were collected at depths of 0–15 cm showed that the s-metolachlor and acetochlor treatments had the dry weight of wheat was not differ with hoeing method and farmer practice. The soil depth of 15–30 cm revealed that the application of s-metolachlor at a rate of 340 grams of active ingredient per Rai, either 7 DAP.