Department of Agronomic, Universidade Federal Rural do Semi-Árido, Mossoró, Rio Grande do Norte, Brazil.
Department of Crop Production, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.
PLoS One. 2020 Nov 25;15(11):e0242350. doi: 10.1371/journal.pone.0242350. eCollection 2020.
In Brazil, the atrazine has been applied frequently to join with glyphosate to control resistant biotypes and weed tolerant species to glyphosate. However, there are no studies about atrazine's behavior in soil when applied in admixture with glyphosate. Knowledge of atrazine's sorption and desorption mixed with glyphosate is necessary because the lower sorption and higher desorption may increase the leaching and runoff of pesticides, reaching groundwaters and rivers. Thereby, the objective of this study was to evaluate the adsorption mechanisms of atrazine when isolated and mixed with glyphosate formulations in a Red-Yellow Latosol. The maximum adsorbed amount of atrazine in equilibrium (qe) was not altered due to glyphosate formulations. The time to reach equilibrium was shortest when atrazine was mixed with the Roundup Ready® (te = 4.3 hours) due to the higher adsorption velocity (k2 = 2.3 mg min-1) in the soil. The highest sorption of atrazine occurred when mixed with the Roundup WG®, with the Freundlich sorption coefficient (Kf) equal to 2.51 and 2.43 for both formulation concentrations. However, other glyphosate formulations did not affect the sorption of atrazine. The desorption of atrazine was high for all treatments, with values close to 80% of the initial adsorbed amount, without differences among isolated and mixed treatments. The change in the velocity and capacity of sorption for the atrazine mixed with some glyphosate formulations indicates that further studies should be conducted to identify the mechanisms involved in this process.
在巴西，莠去津经常与草甘膦联合使用，以控制抗草甘膦生物型和耐草甘膦杂草。然而，目前还没有关于莠去津与草甘膦混合使用时在土壤中行为的研究。了解莠去津与草甘膦混合时的吸附和解吸情况是必要的，因为较低的吸附和较高的解吸可能会增加农药的淋溶和径流，从而到达地下水和河流。因此，本研究的目的是评估莠去津在单独使用和与草甘膦制剂混合使用时在红壤黄壤中的吸附机制。由于草甘膦制剂的存在，莠去津在平衡时的最大吸附量（qe）没有改变。当莠去津与农达®（te = 4.3 小时）混合时，达到平衡的时间最短，这是由于土壤中更高的吸附速度（k2 = 2.3 mg min-1）。当莠去津与 Roundup WG®混合时，莠去津的吸附量最高，两种制剂浓度的 Freundlich 吸附系数（Kf）分别为 2.51 和 2.43。然而，其他草甘膦制剂并不影响莠去津的吸附。所有处理的莠去津解吸率都很高，接近初始吸附量的 80%，单独和混合处理之间没有差异。莠去津与某些草甘膦制剂混合后吸附速度和容量的变化表明，应该进行进一步的研究以确定涉及该过程的机制。
