塔吉克斯坦不同土地利用方式对土壤微生物区系及活性的影响

Effects of Different Land Uses on Soil Microflora and Activity in Tajikistan

通过对塔吉克斯坦哈特隆州具典型代表性7种土地利用方式下的土壤微生物菌群数量、组成和活性测定,分析微生物指标与土壤肥力的相关性,比较不同土地利用方式下的土壤品质现状及趋势。结果表明,天然草地土壤微生物菌群数量最为丰富,显著高于农田土壤（P〈0.05）。农田土壤细菌数、放线菌数、氨化细菌、硝化细菌、好气性固氮菌数量较天然草地均呈现明显下降趋势,而真菌菌群数量呈现一定幅度的增加。不同土地利用方式改变土壤菌群组成,天然草地土壤细菌/真菌（B/F值）和放线菌/真菌（A/F值）分别高于各类耕种农田土壤的10.59-86.23和6.99-20.66倍;农田土壤微生物呼吸强度有不同程度下降,菌群结构向肥力降低和抗干扰能力削弱方向转化。相关性分析显示,土壤细菌数、放线菌数、好气性固氮菌、微生物总数、呼吸强度与土壤有机质、碱解氮、速效钾呈显著相关。综合各项微生物指标,对不同土地利用方式下土壤营养水平分析排序为天然草地〉李子树//棉花间作〉水浇地小麦〉樱桃树//棉花间作〉旱地小麦〉地膜栽培滴灌棉花〉露地栽培沟灌棉花。

Considering 7kinds of land use types in Hatelong,Tajikistan,the amount and structure of the soil microbial community and cellulolytic activity were investigated to analyze the correlation coefficients between the soil indicators and soil properties and comparing the status and trends of soil quality.The results showed that the soil microbial amount in piedmont grass was the richest,significantly more than other farmlands（P〈0.05）.Compared with piedmont grass,in farmlands the amount of bacteria,actinomyces,ammonifying bacteria,nitrobacteria and aerobic nitrogen-fixing bacteria were decreased,while fungi increased.The structure of the soil microbial community was influenced by different land uses.Comparing with piedmont grass,the ratios of bacteria to fungi（B/F）and actinomycetes to fungi（A/F）in other farmland soil decreased by 10.59-86.23times and 6.99-20.66times.Moreover,farmland soil resulted in soil respiration intensity reducing.Significant correlations were found between bacteria,actinomyces,aerobic nitrogen-fixing bacteria,total microbial,respiration intensity with organic matter,available nitrogen,and available potassium.Comprehensive various microbial indicators,the order of nutrient level was as followed：piedmont grass〉intercropping of plum tree and cotton〉irrigated wheat〉intercropping of cherry tree and cotton〉dry land wheat〉 mulch drip irrigation cotton〉open furrow irrigation cotton.