State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China; Soil Physics and Land Management, Wageningen University & Research, P.O. Box 47, 6700 AA, Wageningen, the Netherlands; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Soil Physics and Land Management, Wageningen University & Research, P.O. Box 47, 6700 AA, Wageningen, the Netherlands.
Environ Pollut. 2018 Nov;242(Pt A):338-347. doi: 10.1016/j.envpol.2018.07.006. Epub 2018 Jul 3.
The intensive use of pesticide and plastic mulches has considerably enhanced crop growth and yield. Pesticide residues and plastic debris, however, have caused serious environmental problems. This study investigated the effects of the commonly used herbicide glyphosate and micrometre-sized plastic debris, referred as microplastics, on glyphosate decay and soil microbial activities in Chinese loess soil by a microcosm experiment over 30 days incubation. Results showed that glyphosate decay was gradual and followed a single first-order decay kinetics model. In different treatments (with/without microplastic addition), glyphosate showed similar half-lives (32.8 days). The soil content of aminomethylphosphonic acid (AMPA), the main metabolite of glyphosate, steadily increased without reaching plateau and declining phases throughout the experiment. Soil microbial respiration significantly changed throughout the entirety of the experiment, particularly in the treatments with higher microplastic addition. The dynamics of soil β-glucosidase, urease and phosphatase varied, especially in the treatments with high microplastic addition. Particles that were considerably smaller than the initially added microplastic particles were observed after 30 days incubation. This result thus implied that microplastic would hardly affect glyphosate decay but smaller plastic particles accumulated in soils which potentially threaten soil quality would be further concerned especially in the regions with intensive plastic mulching application.
农药和塑料薄膜的大量使用极大地促进了作物的生长和产量。然而，农药残留和塑料碎片造成了严重的环境问题。本研究通过 30 天的微宇宙实验，研究了常用除草剂草甘膦和称为微塑料的微米级塑料碎片对中国黄土土壤中草甘膦降解和土壤微生物活性的影响。结果表明，草甘膦的降解是逐渐的，并遵循单一的一级降解动力学模型。在不同的处理（有/无微塑料添加）中，草甘膦表现出相似的半衰期（32.8 天）。土壤中氨甲基膦酸（AMPA）的含量，草甘膦的主要代谢物，在整个实验过程中稳步增加，没有达到平台和下降阶段。土壤微生物呼吸在整个实验过程中发生了显著变化，特别是在高微塑料添加的处理中。土壤β-葡萄糖苷酶、脲酶和磷酸酶的动态变化尤其明显，特别是在高微塑料添加的处理中。经过 30 天的培养后，观察到比最初添加的微塑料颗粒小得多的颗粒。因此，这一结果表明微塑料几乎不会影响草甘膦的降解，但在土壤中积累的更小的塑料颗粒可能会对土壤质量构成威胁，特别是在塑料薄膜应用广泛的地区，这一点需要进一步关注。
