行间生草葡萄园土壤微生物量与土壤养分的通径分析

在酿酒葡萄(Vitis vinifera)园行间播种白三叶草(Trifolium repens L.)、紫花苜蓿(Medicago sativa L.)和高羊茅(Festuca arundinacea Schreb),以清耕为对照,研究了土壤微生物量、土壤微生物呼吸强度和土壤微生物熵的变化及其与土壤养分的关系。结果表明:与清耕(对照)相比,白三叶草和紫花苜蓿处理显著提高了土壤有机质、全氮含量,显著降低了速效磷含量;而高羊茅处理土壤有机质和速效钾含量显著低于清耕。白三叶草、紫花苜蓿和高羊茅处理土壤微生物量C含量分别比清耕增加65.2%,61.6%和6.7%;微生物量N含量分别比清耕增加53.6%,52.4%和15.0%。各生草处理土壤微生物熵均显著高于清耕,但土壤微生物呼吸强度与清耕之间无显著差异。微生物学指标总体与土壤有机质、全氮、碱解氮、速效钾呈显著或极显著正相关,与全磷和速效磷呈显著或极显著负相关。通径分析表明,碱解氮、全氮是影响土壤微生物量C、N和微生物呼吸强度、微生物熵重要的直接作用因子。

Path Analysis Between Soil Microbial Biomass and Soil Nutrient Contents in Cover Cropping System of Vineyard

Two perennial legumes(white clover and alfalfa) and a perennial grass(tall fescue) were sown in inter-rows of Cabernet sauvignon vineyard.The effects of inter-row cover cropping on soil microbial biomass,respiration strengths,microbial quotient,soil nutrient contents and their relationships were studied with clean tillage as control.Results showed that white clover and alfalfa increased the contents of soil organic matter and soil total N significantly,and decreased available P contents;tall fescue significantly decreased soil organic matter and available K contents.The soil microbial biomass carbon contents of white clover,alfalfa and tall fescue increased 65.2%,61.6%,6.7%,respectively,and soil microbial biomass nitrogen contents increased 53.6%,52.4%,15.0%,respectively,compared with control.The soil microbial quotients in cover cropping treatments were increased significantly,but the soil respirations had no significant differences between cover crop treatments and control.The soil microbial indicators showed significant positive correlations with soil organic matter,total N,hydrolyzable N and available K,and significant negative correlations with total P and available P.Path analysis indicated that in the vineyard intercropping system,soil hydrolyzable N and total N were direct factors affecting the accumulation of soil microbial biomass,respiration strengths and microbial quotient.