生物降解地膜对土壤微生物丰度、活性及群落结构的影响 - 土壤碳循环与地膜覆盖课题组

【目的】推广生物降解地膜有望从根本上解决农田土壤残膜污染问题，但目前其对土壤微生物的影响情况尚不明确，这一定程度上限制了生物降解地膜在农业上的应用和推广。【方法】本研究基于2018年在辽宁阜新和海城建立的地膜覆盖玉米定位试验（试验设计相同，包含透明、黑色生物降解地膜和透明、黑色塑料地膜覆盖，以及不覆膜处理），测定了2019年春季土壤呼吸速率和春秋两季的土壤水解酶活性（β-葡萄糖苷酶、半纤维素酶、N-乙酰葡萄胺糖苷酶、亮氨酸氨基肽酶和酸性磷酸酶）、微生物量碳氮含量、磷脂脂肪酸（PLFA）含量。【结果】地膜短期覆盖对土壤可溶性有机碳、酶活性、微生物量碳氮及PLFA含量无显著影响。对于两个试验地点，覆盖生物降解地膜土壤呼吸速率均表现高于塑料地膜的趋势，说明生物降解地膜有提高微生物活性的潜力。【结论】生物降解地膜的应用在短期内没有对土壤微生物活性产生负面影响，但不同类型地膜对土壤的长期影响仍需要进一步监测和综合评价。Biodegradable film mulching (BFM) is likely an ultimate solution for plastic film pollution in farmland soil. However, the effect of BFM on soil microorganisms is unclear, which would limit the application of biodegradable plastic film mulch in agriculture. In 2018, we built a BFM field experiment both in Fuxin and Haicheng, Liaoning Province, replicately. They had the same experiment design with five treatments, including clear and black biodegradable film mulching, clear and black traditional plastic film mulching, and no mulching. Soil respiration rate, hydrolytic enzyme activities, microbial biomass and phospholipid fatty acid (PLFA) were measured in the spring and autumn of 2019. The results showed short-term plastic film mulching had no effect on soil dissolved organic carbon, enzyme activities, microbial biomass and PLFA. However, soil respiration rate was higher under BFM than under traditional plastic film mulching in both sites, suggesting that BFM can enhance soil microbial activity. The long-term impact of biodegradable film mulching on soil microorganisms is necessary, although short-term biodegradable film mulching does not affect soil microorganisms.