塔吉克斯坦不同土地利用方式对土壤微生物群落功能多样性的影响

Effects of different land use types on diversity of microbial community function in Tajikistan

利用Biolog EcoplateTM技术对塔吉克斯坦国哈特隆州具有典型代表性的土地利用方式土壤微生物代谢功能多样性分析,为制订合理的土壤管理措施防止土壤退化提供科学依据。结果表明:不同土地利用方式下土壤微生物群落代谢活性差异显著,对总碳源利用强度的大小顺序为:山前草地>水浇地小麦>李子树//棉花间作>地膜栽培滴灌棉花>旱地小麦>樱桃树//棉花间作>露地栽培沟灌棉花。根据不同土地利用方式土壤微生物碳源利用模式差异将其划分为4类功能群。主成分分析显示,氨基酸、碳水化合物及羧酸类碳源是影响土壤微生物活性的重要碳源。Shannon、McIntosh指数的总体趋势是山前草地>地膜栽培滴灌棉花>露地栽培沟灌棉花>水浇地小麦>李子树//棉花间作>旱地小麦>樱桃树//棉花间作,而Simpson指数除山前草地外,其他农田土壤间差异不显著。研究结果证明,各种农田用地土壤微生物群落代谢功能与天然草地相比均呈现出不同程度的衰减趋势。合理的水、肥投入和管理,有利于丰富农田土壤微生物群落功能多样性,减轻土壤生物功能退化程度。

Changes in functional diversity of soil microbial community under different land use patterns in Tajiki- start were investigated in order to provide scientific instructions to develop rational measures for preventing soil deg- radation and realizesustainable use of resources. By using BIOLOG Eco plate system, seven kinds of typical land use patterns were selected in Khatlon that is the major agriculture region of the country for taking and analyzing soil sam- ples to compare the properties in soil microbial community functional diversity. The results showed that the utiliza- tion activity, kind and amount of carbon source used by microbial community under different land use types varied markedly. The AWCD （average well color development） values were changed in the following order： natural grass- land＇ s〉irrigated wheat＇ s〉plum tree and cotton intercropping＇ s〉mulch drip irrigation cotton＇ s〉dry land wheat＇ s〉 cherry tree and cotton intercropping＇ s〉open furrow irrigation cotton＇ s. The functional groups were divided into four types according to carbon utilization models of soil microbial community in different land use types. The Principal Component Analysis （PCA） identified 3 principal component factors in relation to carbon sources, explaining 73.9%, 9.3% and 7.7% of the variation respectively. Sixteen categories of carbon sources were significantly positive- ly related to the principal component 1 （PC 1 ）, and carbohydrates, amino acids and derivatives were the main carbon resources separating the 3 principal component factors. The differences of Shannon and McIntosh index values in mi- crobial functional diversity were holistically in an order of natural grassland〉open furrow irrigation cotton〉mulch drip irrigation cotton〉irrigated wheat〉intercropping of plum tree and cotton〉dry land wheat〉intercropping of cherry tree and cotton, while no significantly different existed for Simpson index in cultivated lands except the natural grass- land. It was suggested that soil microbial community functional diversities were quite different under different land use patterns. The carbon utilization efficiency in natural grassland was significantly higher than in the others, and de- crease of soil biological properties and biochemical function in the cultivated lands may result in deterioration of soil quality. Also, rational fertilization, irrigation practices and land management could increase the metabolic activity of communities for carbon and improve the functional diversity.