不同覆盖方式对黄土高原地区苹果园土壤 有机碳组分及微生物的影响

【目的】研究不同覆盖方式对黄土高原地区苹果园土壤有机碳各组分及微生物群落活性的影响。【方法】通过野外果园定位试验，分层采集0—100 cm土层的土样，对麦草覆盖、起垄黑地膜覆盖及清耕3个不同处理方式下，土壤有机碳各组分及微生物群落功能多样性进行研究。【结果】麦草覆盖可显著增加0—60 cm土壤总有机碳（TOC）、颗粒有机碳（POC）、轻质有机碳（LFOC）、易氧化有机碳（ROC）和可溶性有机碳（DOC）含量，在1—3年内随着覆盖年限的增加而增加，其中在0—20 cm土层中TOC含量每年约增加1.9 g•kg-1，而微生物量碳（MBC）的含量表现出逐年降低的趋势。起垄黑地膜覆盖的土壤TOC含量低于对照，而POC、LFOC、ROC、DOC、MBC的含量高于对照，但均随着覆盖年限的增加而降低，3年后0—20 cm土层中TOC含量降低0.91 g•kg-1。麦草覆盖和黑地膜覆盖处理的微生物群落碳源利用率（AWCD）、微生物群落Shannon 指数（H）和微生物群落丰富度指数（S）均高于对照处理，同样也表现出逐年降低的趋势，其中覆膜处理下降更加剧烈。【结论】麦草覆盖提高了土壤有机碳各组分的含量，而起垄黑地膜覆盖逐年降低有机碳各组分含量。两处理开始均可提高土壤微生物群落碳源利用率、微生物群落的丰富度和功能多样性，但同样出现了逐年降低的趋势，而覆膜处理降低得更加迅速。

Effects of Different Mulching on Soil Organic Carbon Fractions and Soil Microbial Community of Apple Orchard in Loess Plateau

【Objective】The objective of this study was to investigate the characteristics of soil total organic carbon, labile organic carbon and soil microbial community under different mulching treatments for one to three years in apple orchards in the Loess Plateau. 【Method】Long-term orchard experiments were carried out, and soil samples were taken from 0-100 cm soil layers to study the effects of different mulching treatments on various soil organic carbon fractions and soil microbial community. The experiment consists of three mulching treatments: straw mulching, black plastic-film mulching, and bare tillage. 【Result】Compared with bare tillage, straw mulching significantly increased soil total organic carbon contents, particulate organic carbon contents, light fraction organic carbon contents, dissolved organic carbon contents and readily oxidizable organic carbon content in 0-60 cm soil layers, and increased with the increased years of coverage in one to three years, in which soil total organic carbon contents increased by 1.9 g•kg-1 per year in 0-20 cm soil layers. But the microbial biomass carbon contents tended to decrease with the increased years of coverage. In the black plastic-film mulching treatment, soil total organic carbon contents were less than the control, but labile organic carbon contents were higher than the control. Soil total organic carbon contents and labile organic carbon contents both decreased with the increased years of coverage, soil total organic carbon contents decreased by 0.91 g•kg-1 in 0-20 cm soil layers after three years. The results showed that AWCD, Shannon index (H) and Richness index (S) in the straw mulching and plastic-film mulching treatments were higher than the bare tillage, and also decreased with the increased years of coverage. The plastic-film mulching decreased significantly. 【Conclusion】Straw mulching could improve soil organic carbon contents while black plastic-film mulching reduced soil organic carbon contents. Two mulching treatments both increased the diversities of soil microbial community, the utilization rate of carbon source, richness of soil microbial community, and also decreased with the increased years of coverage. But the black plastic-film mulching treatments showed more obviously.