College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
Sci Total Environ. 2022 Jul 20;831:154927. doi: 10.1016/j.scitotenv.2022.154927. Epub 2022 Mar 31.
Plastic film mulching can help farmers meet food production requirements and even increase output. Although the environmental impact of this mulch has received attention, uncertainty remains about certain soil components and the course of its long-term effects. In particular, it is not clear whether the long-term use of mulching film will affect the electron transfer capacity (ETC) of natural organic matter in the soil. This study evaluated the electron-accepting capacity (EAC) and electron-donating capacity (EDC) of soil humic acid (HA) in different-size aggregates in response to different film mulching years (0-6 years). The EAC of HA in the soil showed a downward trend as mulching years increased, while the EDC fluctuated. EAC decline in microaggregates (MIA) was more significant than that of macroaggregates (MAA). Film mulching changes the physical and chemical properties of soil and the activity of enzymes, changes the chemical structure of HA, and ultimately affects HA electron transfer. In addition, compared with that in MAA, the chemical structure of soil HA in MIA has a stronger correlation with enzyme activity and ETC and thus is more significantly affected by mulching. These results provide an in-depth understanding of the role of HA in soil aggregates of different sizes in processes related to the agricultural soil environment under mulching conditions.
塑料薄膜覆盖可以帮助农民满足粮食生产需求，甚至增加产量。尽管这种覆盖物的环境影响已经引起了关注，但某些土壤成分及其长期影响的过程仍然存在不确定性。特别是，长期使用覆盖膜是否会影响土壤中天然有机质的电子传递能力（ETC）还不清楚。本研究评估了不同薄膜覆盖年限（0-6 年）下不同粒径团聚体中土壤腐殖酸（HA）的电子接受能力（EAC）和电子供体能力（EDC）。随着覆盖年限的增加，土壤 HA 的 EAC 呈下降趋势，而 EDC 则波动。微团聚体（MIA）中 EAC 的下降比大团聚体（MAA）更为显著。薄膜覆盖改变了土壤的物理和化学性质以及酶的活性，改变了 HA 的化学结构，最终影响了 HA 的电子传递。此外，与 MAA 相比，MIA 中土壤 HA 的化学结构与酶活性和 ETC 的相关性更强，因此受覆盖的影响更为显著。这些结果深入了解了在覆盖条件下与农业土壤环境相关的过程中，不同大小土壤团聚体中 HA 的作用。
