Soil Physics and Land Management, Wageningen University & Research, P.O. Box 47, 6700 AA, Wageningen, the Netherlands.
Soil Physics and Land Management, Wageningen University & Research, P.O. Box 47, 6700 AA, Wageningen, the Netherlands.
Environ Pollut. 2019 Jan;244:323-331. doi: 10.1016/j.envpol.2018.10.046. Epub 2018 Oct 12.
This study investigates the dynamics of glyphosate and AMPA in the soil surface layer of two fields growing glyphosate-resistant crops in the loess Pampas of Córdoba Province, Argentina. Glyphosate decay and AMPA formation/decay were studied after a single application, using decay kinetic models. Furthermore, glyphosate and AMPA concentrations were investigated in runoff to evaluate their off-site risk. During a 2.5-month study, cultivations of glyphosate-resistant soybean and maize received an application of 1.0 and 0.81 kg a.e. ha, respectively, of Roundup UltraMax. Topsoil samples (0-1, 1-2 cm) were collected weekly (including before application) and analysed for glyphosate, AMPA and soil moisture (SM) contents. Runoff was collected from runoff plots (3 m) and weirs after 2 erosive rainfall events, and analysed for glyphosate and AMPA contents (water, eroded-sediment). Under both cultivations, background residues in soil before application were 0.27-0.42 mg kg for glyphosate and 1.3-1.7 mg kg for AMPA. In the soybean area, the single-first-order (SFO) model performed best for glyphosate decay. In the maize area, the bi-phasic Hockey-Stick (HS) model performed best for glyphosate decay, due to an abrupt change in SM regimes after high rainfall. Glyphosate half-life and DT were 6.0 and 19.8 days, respectively, in the soybean area, and 11.1 and 15.4 days, respectively, in the maize area. In the soybean area, 24% of the glyphosate was degraded to AMPA. In the maize area, it was only 5%. AMPA half-life and DT were 54.7 and 182 days, respectively, in the soybean area, and 71.0 and 236 days, respectively, in the maize area. Glyphosate and AMPA contents were 1.1-17.5 times higher in water-eroded sediment than in soil. We conclude that AMPA persists and may accumulate in soil, whereas both glyphosate and AMPA are prone to off-site transport with water erosion, representing a contamination risk for surface waters and adjacent fields.
本研究调查了阿根廷科尔多瓦黄土高原上两个种植抗草甘膦作物农田土壤表层中草甘膦和 AMPA 的动态。在单次施药后，使用降解动力学模型研究了草甘膦的降解和 AMPA 的形成/降解。此外，还研究了径流中的草甘膦和 AMPA 浓度，以评估其场外风险。在为期 2.5 个月的研究中，种植的抗草甘膦大豆和玉米分别接受了 1.0 和 0.81 kg a.e. ha 的草甘膦 UltraMax 的处理。每周（包括施药前）采集表土样品（0-1、1-2 cm），并分析草甘膦、AMPA 和土壤水分（SM）含量。在两次侵蚀性降雨事件后，从径流场（3 m）和堰收集径流，并分析草甘膦和 AMPA 含量（水、侵蚀沉积物）。在两种作物种植区，施药前土壤中的背景残留量分别为草甘膦 0.27-0.42 mg kg 和 AMPA 1.3-1.7 mg kg。在大豆区，草甘膦降解的单一阶（SFO）模型表现最佳。在玉米区，由于高降雨后 SM 制度的突然变化，双相曲棍球棒（HS）模型对草甘膦降解的表现最佳。草甘膦半衰期和 DT 在大豆区分别为 6.0 和 19.8 天，在玉米区分别为 11.1 和 15.4 天。在大豆区，24%的草甘膦降解为 AMPA。在玉米区，只有 5%。在大豆区，AMPA 半衰期和 DT 分别为 54.7 和 182 天，在玉米区，分别为 71.0 和 236 天。水侵蚀沉积物中的草甘膦和 AMPA 含量分别是土壤中的 1.1-17.5 倍。我们得出结论，AMPA 会在土壤中持续存在并可能积累，而草甘膦和 AMPA 都容易随水侵蚀发生场外迁移，对地表水和相邻农田构成污染风险。
