Abstract: This paper studied the biodegradation of humic acid degradable mulching film  by observing microbial growth through experiments of microbiological degradation and controlled soil-buria. Meanwhile, the weight loss was also measured during degradable mulching film degradation. Microbial number and soil enzyme activities in mulched film soil were tested to explore the impact of used plastic film on the metabolic activities of microbes. The results showed that microorganisms stimulated the degradation of mulch film, fungi played obvious role in film degradation, and film with the highest starch content had fast degradation speed. The intermediate product during film degradation could  increase soil microbial number and color their biochemical activity. Compared with the soil without plastic film, the numbers of bacteria, fungus, and actinomycetes, activities of catalase and sucrase, soil respiration in the soil covered with plastic film were increased by 205.1%, 110.4%, 46.9%, 156.2%, 198.6%, and 24%, respectively. The influences were related not only to the content of humic acid, but also to the degradation degree of the film.

Key words: humic acid, degradable mulching film, biodegradability, soil microorganism

摘要： 为研究腐植酸可降解地膜的生物降解性，采用微生物降解试验和受控埋土试验观察微生物生长情况，并测定了可降解地膜在降解过程中的重量损失；以埋有地膜的土壤为材料测定了微生物数量和土壤酶活性，探讨了残膜对土壤微生物代谢活动的影响。结果表明：微生物对地膜的降解起促进作用，真菌对地膜降解的影响最为明显，且淀粉含量最高的地膜降解速度最快；地膜降解的中间产物能促进土壤微生物的数量和生化活性，与无地膜填埋土壤相比，埋有地膜a土壤的细菌数量提高了205.1%，真菌数量提高了110.4%，埋有地膜b土壤的放线菌数量提高了46.9%；埋有地膜b土壤的过氧化氢酶活性提高了156.2%，埋有地膜a土壤的蔗糖酶活性提高了198.6%，埋有地膜b土壤的呼吸强度提高了24%，其影响不仅与腐植酸含量有关，还与地膜的降解程度有关。

关键词: 腐植酸, 可降解地膜, 生物降解性能, 土壤微生物