中文摘要：

利用群落水平生理活性（CLPPs）和磷脂脂肪酸（PLFAs）方法，研究人工苜蓿、谷子、青贮玉米、原始群落等土地利用方式对宁夏中部干旱区荒漠草原土壤微生物群落结构与功能的影响。结果表明：不同土地利用方式显著改变革兰氏阳性菌（18：lngc）、腐生真菌（18：2n6t）的生物量。青贮玉米、苜蓿利用方式下，土壤细菌、真菌的微生物生物量分别比谷子利用方式高0．79～1．41倍、0．84～0．94倍；革兰氏阳性菌（G＋）、革兰氏阴性菌（G-）的生物量比谷子利用方式高0．33～1．00。倍、1．05～1．64倍，革兰氏阴性菌（G-）的生物量增加幅度显著高于革兰氏阳性菌（G＋）。和典型植被群落相比，玉米、谷子利用方式真菌在微生物群落中所占比例分别提高了16．87％、32．51％，土地利用方式会改变土壤真菌所占比例，加速了土壤向“真菌型”转化的速度。苜蓿、青贮玉米利用方式提升了以碳水化合物、芳香化合物、氨基酸类化合物为碳源的微生物类群代谢功能多样性，以羧酸类化合物为碳源的微生物类群受土地利用方式影响较小；然而，谷子利用方式下微生物群落对芳香类化合物利用能力明显较强，以羧酸类和氨基酸类化合物为碳源的微生物类群明显受到抑制。土壤微生物群落结构、功能多样性受土地利用方式影响出现差异；RDA分析表明以碳水化合物、芳香类化合物、氨基酸类化合物为碳源的微生物类群和土壤碱解氮正相关，以多聚化合物为碳源的微生物类群和土壤全磷质量分数呈正相关。革兰氏阴性菌、革兰氏阳性菌的变化显著受到土壤全磷质量分数的影响。不同土地利用方式下土壤碱解氮、全磷质量分数会对土壤微生物结构与功能产生影响，土壤微生物群落结构、功能多样性的变化是土壤因子与微生物相互作用的结果。

英文摘要：

Using community level physiological profiles（CLPPs） of Biolog GN plate and phospholipids fatty acids（PLFAs） biomarker method, with different land-use patterns such as the artificial alfalfa, silage corn, millet and natural vegetation community in the middle arid region of Ningxia, we studied the diversity of soil microbial structure and function of desert grassland. The results showed that the biomass of gram-positive bacteria （ 18 ： 1n9c）, saprophytic fungi （18 ： 2n6t ） had been influenced significantly. Microbial biomass of bacteria and fungi were increased 0.79-1.41 times,0.84-0.94 times respectively under the land-use patterns of alfalfa and corn. Compared with the millet, the biomass of gram-negative bacteria （G-） and the gram positive bacteria（G＋） were over 0. 33--1.00 times and 1.05-- 1.64 times. The increased rate of biomass of gram-negative bacteria （G-） in soil was obviously greater than the gram positive bacteria（G＋ ）. Compared with the natural vegetation communities, the proportion of fungi in soil microbial community had been changed under the different land managements, the rate of fungi under corn, millet use patterns were increased by 16. 87%, 32. 51%, the change of soil microorganism from bacteria of soil type to fungi of soil type accelerated. The metabolic function diversity of the major microbial groups was enhanced significantlyunder the alfalfa, corn use patterns,these major microbial groups used the carbohydrates, aromatic compounds, amino compounds as the main carbon source, but the microbial groups still had a stronger utilization ability to aromatic compounds and nearly had not influenced by land-use patterns. However, soil microbial communities still had a weaken utilization ability on carboxylic acids compounds and amino compounds for millet using pattern and had a strong utilization ability for aromatic compounds as carbon source. Soil microbial community structure and function diversity showed a obviously different spatial distribution pattern