Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, National Agricultural Experiment Station for Agricultural Environment (Liuhe), Key Laboratory for Combined Farming and Raising, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Murdoch Applied Innovation Nanotechnology Research Group/Surface Analysis and Materials Engineering Research Group, College of Science, Health, Engineering and Education, Murdoch University, Perth, WA 5150, Australia.
Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Sci Total Environ. 2022 Nov 15;847:157635. doi: 10.1016/j.scitotenv.2022.157635. Epub 2022 Jul 26.
Microplastics (MPs) are verified to affect the fate of ammonia (NH) in agricultural soils. However, the impacts and mechanisms of MPs coupled with biochar (BC), a widely used agricultural conditioner, on NH losses are mostly untapped. The aim of this study was to investigate the mechanisms of common MPs (i.e., polyethylene, polyester, and polyacrylonitrile) and straw-derived BC on NH volatilization in rice-wheat rotation soils. Results showed that BC alone and MPs with BC (MPs + BC) reduced 5.5 % and 11.2-26.6 % cumulative NH volatilization than the control (CK), respectively, in the rice season. The increased nitrate concentration and soil cation exchange capacity were dominant contributors to the reduced soil NH volatilization in the rice season. BC and MPs + BC persistently reduced 44.5 % and 60.0-62.6 % NH losses than CK in the wheat season as influenced by pH and nitrate concentration. Moreover, BC and MPs + BC increased humic acid-like substances in soil dissolved organic matter by an average of 159.1 % and 179.6 % than CK, respectively, in rice and wheat seasons. The increased adsorption of soil NH and the promotion of crop root growth were the main mechanisms of NH reduction. Our findings partially revealed the mechanisms of the coexistence of MPs and BC on NH mitigation in rice-wheat rotational ecosystems.
微塑料（MPs）已被证实会影响农业土壤中氨（NH）的命运。然而，与生物炭（BC）结合的 MPs 对 NH 损失的影响和机制在很大程度上尚未被开发。本研究旨在研究常见 MPs（即聚乙烯、聚酯和聚丙烯腈）和秸秆衍生的 BC 对水稻-小麦轮作土壤中 NH 挥发的影响机制。结果表明，与对照（CK）相比，BC 单独和 MPs 与 BC（MPs + BC）分别减少了 5.5%和 11.2-26.6%的累积 NH 挥发。在水稻季，增加的硝酸盐浓度和土壤阳离子交换容量是导致土壤 NH 挥发减少的主要原因。BC 和 MPs + BC 持续减少了 44.5%和 60.0-62.6%的 NH 损失，比 CK 低，这主要受 pH 值和硝酸盐浓度的影响。此外，BC 和 MPs + BC 分别比 CK 增加了 159.1%和 179.6%的土壤溶解性有机质中腐殖酸类物质。增加土壤 NH 的吸附和促进作物根系生长是减少 NH 的主要机制。我们的研究结果部分揭示了 MPs 和 BC 共存对水稻-小麦轮作生态系统中 NH 减排的作用机制。
