Lu Xiaonan, Wang Lili, Guggenberger Georg, Sun Yue, Hu Runan, Li Tingxuan
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China.
Institute of Earth System Sciences, Section Soil Science, Leibniz Universität Hannover, 30419, Hannover, Germany.
J Environ Manage. 2025 May;381:125296. doi: 10.1016/j.jenvman.2025.125296. Epub 2025 Apr 12.
The persistence of farmland microplastic (MP) pollution has raised significant concerns regarding its effects on soil organic carbon (SOC) pools in the context of soil pollution but also of global climate change. Nevertheless, the effect of MPs on SOC mineralization as well as dissolved organic carbon (DOC) transformation with different water levels in paddy soils remained uncertain. In this study, we investigated the effect of micro polyethylene (PE) on SOC decomposition in paddy soils under alternating wet and dry (AWD) and continuous flooding (CF) conditions through a 205-day microcosm experiment. Polyethylene addition reduced cumulative CO emissions by 5.1-14.8 % under both water conditions. The presence of PE influenced SOC mineralization under CF conditions by diminishing the activity of cellobiohydrolase enzymes and increasing the microbial community diversity. Conversely, at AWD the addition of PE impeded SOC mineralization by reducing the activity of polyphenol oxidase enzymes. However, PE addition resulted in higher DOC content and at low dose of PE addition (0.25 % w/w) increased DOM bioavailability. The most significantly positive effect was found with the addition of 1 % w/w PE, which increased DOC content by 37.2 % and 18.5 % compared to Control (CK) under AWD and CF conditions, respectively. The strong correlation observed between DOC and mineral-associated organic carbon (MAOC) concentrations might result from DOC adsorbed to mineral surfaces to form MAOC and then affect SOC mineralization. Accordingly, AWD is a more efficient management to attenuate the impact of MPs on SOC decomposition compared to CF. Our study is noteworthy in the development of sustainable agricultural practice management in plastic-contaminated soil-crop systems.
农田微塑料（MP）污染的持续存在引发了人们对其在土壤污染以及全球气候变化背景下对土壤有机碳（SOC）库影响的重大担忧。然而，微塑料对水稻土中SOC矿化以及不同水位下溶解有机碳（DOC）转化的影响仍不确定。在本研究中，我们通过为期205天的微观实验，研究了微聚乙烯（PE）在干湿交替（AWD）和持续淹水（CF）条件下对水稻土中SOC分解的影响。在两种水分条件下，添加聚乙烯均使累积CO排放量降低了5.1-14.8%。在CF条件下，PE的存在通过降低纤维二糖水解酶的活性和增加微生物群落多样性来影响SOC矿化。相反，在AWD条件下，添加PE通过降低多酚氧化酶的活性阻碍了SOC矿化。然而，添加PE导致DOC含量更高，并且在低剂量添加PE（0.25% w/w）时增加了DOM的生物有效性。添加1% w/w PE时发现最显著的积极影响，与对照（CK）相比，在AWD和CF条件下，DOC含量分别增加了37.2%和18.5%。DOC与矿物相关有机碳（MAOC）浓度之间观察到的强相关性可能是由于DOC吸附到矿物表面形成MAOC，进而影响SOC矿化。因此，与CF相比，AWD是一种更有效的管理方式，可减轻微塑料对SOC分解的影响。我们的研究在受塑料污染的土壤-作物系统中可持续农业实践管理的发展方面值得关注。
