生草对渭北旱地苹果园土壤有机碳组分及微生物的影响

在渭北旱地苹果园行间播种毛苕子（Vicia villosa）、白三叶（Trifolium repens）、黑麦草（Lolium perenne）和早熟禾（Poa pratensis），以清耕为对照，对0100 cm土层的土壤有机碳各组分及微生物群落功能多样性进行研究。结果表明，行间生草可显著增加040 cm土层土壤的总有机碳（TOC）、颗粒有机碳（POC）、轻质有机碳（LFOC）、易氧化有机碳（ROC）、可溶性有机碳（DOC）和微生物量碳（MBC），豆科牧草毛苕子和白三叶的各有机碳含量总体上高于禾本科牧草黑麦草和早熟禾。其中在020 cm土层中，豆科牧草的TOC含量平均每年增加约1.2 g/kg，禾本科牧草每年增加约0.9 g/kg。生草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）均高于清耕处理，其中豆科牧草的微生物活性更高。因此，生草可以提高土壤有机碳各组分的含量、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，豆科牧草毛苕子和白三叶提高效应更加明显。

Effects of inter-row planting grasses on soil organic carbon fractions and soil microbial community of apple orchard in Weibei dryland

 Two perennial legumes (hairy vetch and white clover) and two perennial grasses(ryegrass and bluegrass) were sown in inter|rows of apple orchard in Weibei dryland. Soil samples were taken from 0-100 cm soil layers to study the effects of planting grasses on various soil organic carbon fractions and soil microbial community with clean tillage as control. Results showed that planting grasses could significantly increase soil total organic carbon content, particulate organic carbon content, light fraction organic carbon content, readily oxidizable organic carbon content, dissolved organic carbon content and microbial biomass carbon content in 0-40 cm soil layer. The contents of soil organic carbon fractions in perennial legume were mostly higher than perennial grass. Soil total organic carbon contents of perennial legume and perennial grass increased 1.2 g/(kg·a) and 0.9 g/(kg·a) in 0-20 cm soil layer, respectively. The AWCD, Shannon index (H) and Richness index (S) in the planting grass treatments were higher than the clean tillage, in which the microbial activity of perennial legume was higher. Therefore, growing grasses could improve soil organic carbon content, diversity of soil microbial community, the utilization rate of carbon source and richness of soil microbial community, in which perennial legumes (hairy vetch and white clover) increased more significantly.