Assessment of Tribenuron Methyl Soil Residual on Crops Germination Properties

Abstract

In recent years, higher doses of tribenuron methyl have been used to control weeds and increase wheat yield, significantly damaging subsequent crops. Therefore, experiments were conducted to determine the appropriate dose of tribenuron methyl (TBM) that has the highest amount of weed control and, at the same time, the minor damage to the next crop. The field experiment was carried out in a randomized complete block design in 2019 and 2020. The TBM doses were 5.62, 11.25 (recommended dose), 16.87, 22.5, and 28.12 g/ha and were applied during the tillering stage of wheat. At the end of the season (wheat harvest), soil sampling was performed in all plots 0, 30, 60, and 90 days intervalley. Then, the seeds of the test plants were cultivated in pots filled with the soil sample of each TBM dose under controlled greenhouse conditions in a completely randomized design. The results showed that the recommended doses and below (11.25 and 5.62 g/ha) did not have good efficacy in reducing weed dry weight (44 and 30% reduction compared to the check; RCC) and weed density (30 and 23% RCC) and consequently had the most negligible effect on chickpea, corn, lentil, cucumber, and canola emergence and other measured traits. The dose of 1.5 folds TBM (16.87 g ai ha⁻¹) had a more significant effect on reducing the mentioned traits (73 and 60% respectively), the yield of wheat was at its maximum (70% increase compared to the check), which did not differ significantly with higher doses. This dose had the adverse effect on test plant and reduced measured traits by 15 to 35% compared to the check. Its notable, that the detrimental effect of this dose over the time (60, 90 days after wheat harvest) significantly decreased compared to the higher doses. Finally, it is suggested to use the recommended dose at the proper time, which has the least negative effect on the next cultivated plants. If the use of a higher dose is inevitable, it is recommended to delay the cultivation of the next crop or consider a fallow period to reduce the adverse effects of the herbicide.