民勤绿洲退耕地自然恢复过程中土壤微生物量碳、氮、磷的动态变化

以石羊河下游民勤绿洲内不同退耕年限（1、2、3、4、5、8、15、24、31年）退耕地为对象，分0~10、10~20、20~30、30~40 cm 4个土层，调查分析退耕地在自然修复过程中土壤微生物生物量碳、氮、磷在不同土层、不同退耕年限的动态变化以及和土壤养分的相关性。结果表明：（1）土壤微生物量碳、氮、磷与土壤全氮、速效钾、有效磷之间存在一定的相关性，其中有效磷的含量与土壤微生物量碳、氮、磷之间均存在较显著的正相关性，且其相关系数较全氮和速效钾更高；（2）土壤微生物量在不同深度的土层内随退耕年限的增加其变化规律是不一样的；（3）各土层土壤微生物量之间具有显著差异，土层越深，土壤微生物量越低，并且，随着退耕年限的增加各土层土壤微生物量之间的差异逐渐减小。

Dynamic Change of Soil Microbial Biomass Carbon, Nitrogen and Phosphorus in Natural Recovery Process of Abandoned Farmland in Minqin Oasis

Dynamic change of soil microbial biomass carbon, nitrogen and phosphorus in different vegetation restoration years (1, 2, 3, 4, 5, 8, 15, 24 and 31 a) and different soil layers (0-10, 10-20, 20-30 and 30- 40 cm) and its correlation with soil nutrients in Shiyang River downstream Minqin oasis were analyzed. The results showed that (1) soil microbial biomass carbon, nitrogen and phosphorus had certain relationship with total nitrogen, available potassium and available phosphorus, available phosphorus had an obvious relationship with soil microbial biomass carbon, nitrogen and phosphorus, and the correlation coefficient was higher than that of total nitrogen and available potassium; (2) in different soil layers, the soil microbial biomass had different change rules with different vegetation restoration years; (3) the amount of soil microbial biomass carbon, nitrogen and phosphorus was dramatically different in different soil layers, the soil microbial biomass decreased with the increase of the soil depth, and the difference of soil microbial biomass in different soil layers gradually reduced with the increase of vegetation restoration year.