College of Environmental Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 225127, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Sci Total Environ. 2024 Dec 1;954:176341. doi: 10.1016/j.scitotenv.2024.176341. Epub 2024 Sep 18.
Microplastics are a potential threat to agricultural sustainability. However, the effects of microplastics at environmentally relevant concentrations on the plant-soil-microbiota system in realistic field conditions are largely unknown. Herein, we conducted a two-year field trial to study the effects of polyethylene (PE) microplastics at 0, 100, and 600 mg/kg on crop growth, soil properties, and the composition and function of microbial communities in a farmland with rice-wheat rotation. PE did not affect wheat growth but it increased the rice grain weight by 42.5 % at 600 mg/kg, and enhanced rice height by 35.4 % and 30.2 % at 100 and 600 mg/kg, respectively. The presence of PE significantly decreased soil available phosphorus during the wheat season, while it reduced soil total nitrogen, NH-N and available phosphorus during the rice season. There were five and sixteen bacterial orders identified changed by PE in wheat and rice soils, respectively. Specifically, PE at different concentrations differentially altered the abundances of sulfate-reducing bacteria Thermodesulfovibrionia, Thermoactinomycetales and Syntrophobacterales, and further modified soil sulfate respiration in wheat soils. During the rice season, PE (100 mg/kg) increased the abundance of Xanthomonadales by 98.0 % and enriched the functional groups of intracellular parasites, while PE (600 mg/kg) inhibited twelve cluster of orthologous group function classes and disturbed bacterial metabolism. This study suggests that PE exhibits a greater impact on the plant-soil-microbiota system during the rice season compared to the previous year's wheat season, highlighting the importance of crop type and cultivation practices in determining the environmental risks of microplastics in agroecosystems.
微塑料是农业可持续性的潜在威胁。然而，在现实田间条件下，环境相关浓度的微塑料对植物-土壤-微生物群落系统的影响在很大程度上尚不清楚。在此，我们进行了为期两年的田间试验，研究了聚乙烯（PE）微塑料在 0、100 和 600 mg/kg 下对稻麦轮作农田中作物生长、土壤性质以及微生物群落组成和功能的影响。PE 对小麦生长没有影响，但在 600 mg/kg 时增加了稻谷重量 42.5%，在 100 和 600 mg/kg 时分别增加了水稻高度 35.4%和 30.2%。PE 的存在显著降低了小麦季土壤有效磷含量，而在水稻季则降低了土壤全氮、NH-N 和有效磷含量。在小麦和水稻土壤中分别有 5 个和 16 个细菌目因 PE 而发生变化。具体而言，PE 在不同浓度下差异地改变了硫酸盐还原菌 Thermodesulfovibrionia、Thermoactinomycetales 和 Syntrophobacterales 的丰度，并进一步改变了小麦土壤中的土壤硫酸盐呼吸。在水稻季，PE（100 mg/kg）增加了黄单胞菌目（Xanthomonadales）的丰度 98.0%，并富集了细胞内寄生虫的功能群，而 PE（600 mg/kg）抑制了 12 个同源功能群功能类，并扰乱了细菌代谢。本研究表明，PE 在水稻季对植物-土壤-微生物群落系统的影响大于前一年的小麦季，突出了作物类型和耕作措施在确定农业生态系统中微塑料环境风险方面的重要性。
