中文摘要：

冻融作用对酶和微生物活性具有重要影响,进而影响植物群落的生长发育。为深入了解荒漠优势种梭梭群落冬季土壤生态过程,于2012年10月~2013年10月,对土壤冻融期、冻结期、融冻期和生长季的艾比湖典型样地进行野外实地观测、采样和室内分析。通过对比分析不同冻融阶段土壤含水量、pH值、有机质、全氮、酶活性和微生物数量的变化特征。结果表明：（1）土壤含水量,融冻期〉冻结期〉冻融期〉生长季,土壤pH值,生长季〉融冻期〉冻融期〉冻结期,各土层土壤含水量以浅层土表现最为显著（P〈0.05）,不同冻融阶段各土层pH值差异性较大,冻融期、冻结期和生长季表层土壤pH值较大,融冻期浅层土壤pH值较大。（2）土壤有机质和全氮含量的波动状况相似,分别在融冻期和生长季呈现波峰和波谷,不同土层间全氮和有机质含量差异性较小,以冻融期和生长季表现最为显著（P〈0.05）。（3）土壤酶活性的变化中,过氧化氢酶、脲酶和蛋白酶在融冻期含量最大,冻融期次之,蔗糖酶在冻结期活性最大,土壤微生物数量的变化以融冻期最大,除此之外,各冻融阶段细菌和放线菌占主导,真菌含量相对较少。（4）冻融循环次数分布于冻融期和融冻期,对土壤酶活性和微生物数量具有一定的影响,致使融冻期土壤各因子大于冻融期。

英文摘要：

Freeze-thaw action has an important influence on enzyme and microbial activity, and further affects the growth and development ofphytocoenosium. To gain an insight into the winter soil ecological process of Hal- oxylon ammodendron community-a dominant species in desert, field observation, sampling and indoor analysis were each carried out on a typical sample plot at Ebinur Lake in soil freeze thawing period, freezing period, thaw freezing period and growing season from October, 2012 to October, 2013. By comparatively analyze the change features of the soil moisture content, pH value, organic matter, total nitrogen, enzymatic activity and microbial biomass during different freeze thawing stages, this study got results as follows： （ 1 ） For soil moisture content, it shows： thaw freezing period 〉freezing period 〉freeze thawing period 〉growing season; and for soil pH value, growing season 〉thaw freezing period 〉freeze thawing period 〉freezing period. As for the soil moisture content in each soil layer, shallow soil was the most significant （P 〈0.05）. The pH values of the soil layers during differ- ent freeze thawing stages were quite different, the pH value of the surface soil was larger during freeze thawing period, freezing period and growing season, and the pH value of shallow soil was larger during thaw freezing peri- od. （2） The fluctuations of soil organic matter and total nitrogen content were similar, and the wave crest and wave trough appeared in the freeze thawing period and growing season, respectively. Differences of total nitrogen content and organic matter content among different soil layers are relatively small, and are most significant in the freeze thawing period and growing season （P 〈 0.05） ; （3） For the changes of soil enzyme activity, the maximum content of catalase, urease and protease occurred in thaw freezing period, followed by freeze thawing period; su- crose was most active during freezing period, and the soil microbial biomass changed to maximum duri