科研之友
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摘要
The herbicide metribuzin is recommended for weed control of sugarcane crops. However, the behavior of this herbicide on the straw left on the soil surface of mechanically-harvested sugarcane areas is not very known. This work aimed to evaluate the dynamics of the herbicide metribuzin applied on different amounts of sugarcane straw under different rainfall periods and intensities after application. Three assays were carried out to evaluate the performance of metribuzin applied on sugarcane straw: in assay 1, herbicide interception was assessed by 0, 1, 2.5, 5, 7.5, 10, 15, and 20 t ha(-1) of straw; in assay 2, herbicide leaching through 5, 10, 15, and 20 t ha-1 of straw was evaluated under rain simulation equivalent to 2.5 up to 100 mm rain, one day after application (DAA); and in assay 3, the effect of the time intervals between herbicide application and the first rain on herbicide leaching (0, 1, 7, 14, and 28 days) on the straw (10 t ha-1) was evaluated under the same rainfall amounts simulated in the second study. The results obtained in assays 1 and 2 were adjusted by the Mitscherlich model. The herbicide was quantified by HPLC. The amount of metribuzin passing through the different amounts of straw with simulation of 100 mm of accumulated rain is differentiated, being higher than 5 t ha-1 and lower than higher amounts up to 20 t ha(-1). The mean simulation of rainfall between 20 and 30 mm is sufficient to promote a transposition of metribuzin higher than 99%. Metribuzin is retained when applied on sugarcane straw, lasting for periods up to 28 DAA without rain.
- 出版日期2013-3
