咸水滴灌林地风沙土中微生物群落代谢特征

选择Biolog技术方法，利用方差分析和主成分分析研究了不同矿化度水滴灌下塔里木沙漠公路防护林地土壤微生物的代谢活性。结果表明：随着培养时间的推移，微生物利用单一碳源的颜色平均变化率（AWCD）呈现升高趋势。培养48 h内小于0.5，处于缓慢增长期；48 h后进入对数增长期；216 h后进入稳定期；衰亡期不明显。随着滴灌水矿化度增大，AWCD值明显降低，这种差异主要由土壤微生物对胺类、酚类化合物、碳水化合物利用的差异所致。土壤微生物群落利用碳源活性的垂直差异明显，70~100 cm土层是AWCD值最高的区域，表层0~5 cm最小。AWCD值与土壤有机质、全氮、全磷、全钾、速效钾、速效磷的含量、pH值、阳离子交换量、容重的正相关系数均大于0.85。因此，土壤微生物利用碳源的代谢活性差异主要由土壤化学性质所致，土壤全量养分和酸碱度是主要驱动因子。胺类、酚类化合物、碳水化合物是区分不同矿化度水滴灌下土壤微生物群落生态功能的敏感碳源。

Characteristics of Sandy Soil Microbial Metabolisms in the Forests Drip-irrigated with Saline Water

The microbial metabolism activities in the sandy soils of the forests drip-irrigated with different saline water were investigated by Biolog method in this study. The main results are as below: (1) The microbial utilization capability of single carbon source (referred as AWCD value) continuously improved with increase of culturing time, the AWCD value was less than 0.5 and at a slow increasing stage within 48 h, then entered into a logarithm increasing stage after 48 h, a steady stage appeared after 216 h, but a declining stage was not found. (2) The AWCD values decreased notably with increasing salinity of the drip irrigation water, which mainly caused by differences of the microbial utilization capabilities of carbon sources including amine, phenolic compounds and carbohydrate among the different soil samples. (3) Vertical variations of the AWCD values among the different soil layers were significant, the biggest was at 70-100 cm, and the minimum was at the soil surface. (4) The positive correlation coefficients between AWCD vales and soil physical and chemical factors including contents of organism, total nutrient (N, P, K), available nutrient (N, P, K), pH value, cation exchange amount and bulk density, were greater than 0.85. So, the differences of microbial capabilities of utilizing the carbon sources could be subjected to the soil chemical properties; especially to the soil nutrient content and acidity-alkalinity. Amine, phenolic compounds and carbohydrate were regarded as sensitive carbon sources for distinguishing the soil microbial communities from the different drip-irrigated forest lands.