沙柳沙障腐烂过程对土壤微生物生物量及酶活性的影响

为探究沙柳沙障腐烂过程土壤微生物生物量及酶活性的变化规律,以铺设10年的沙柳沙障为研究对象,采用野外原位取样和室内指标测定法,结合RDA多元数据排序分析,揭示影响土壤微生物生物量及酶活性的主要环境因子。结果表明:(1)随铺设年限的增加,土壤中的C:N与C:P呈上升趋势,10年后的C:N是1年的16.14倍,而N:P呈下降趋势,10年后下降83.96%;(2)随腐烂程度的加剧,土壤MBC、MBN与MBP均呈先上升后下降趋势,7年均达到最大值,分别为1年的2.67,2.18,1.43倍;(3)土壤碱性磷酸酶活性随铺设年限增加呈先上升后下降趋势,6年时最大且表现出显著性差异(P<0.05),但脲酶与蔗糖酶活性均为1年时显著大于其他各组(P<0.05);(4)RDA分析结果表明,土壤理化因子对土壤微生物生物量及酶活性影响的大小顺序为速效钾>含水率>碳氮比>碱解氮>酸碱度>速效磷>氮磷比>碳磷比,即速效钾与含水率为主要驱动因子。研究结果对进一步探讨荒漠生态系统土壤 碳、氮、磷养分循环提供了重要的理论依据。

Effects of Salix psammophila Sand Barriers Decay on Soil Microbial Biomass and Enzymes Activities

The purpose of this study was to investigate the changes in soil microbial biomass and enzymes activities during the decaying of Salix psammophila sand barriers. The sand barriers which had been laid for ten years were used as the research object. The research methods included field in-situ sampling and laboratory tests. Combined with RDA data sequencing analysis, the main environmental factors affecting soil microbial biomass and enzymes activities were revealed. The results showed that the values of C:N and C:P in soil increased with the increase of laying years. The C:N value in 10 years was 16.14 times of that in one year, while the N/P decreased by 83.96% after 10 years. The soil MBC, MBN and MBP increased firstly and then decreased with the decaying, and reached the maximum value in the 7th year, which was 2.67, 2.18 and 1.43 times that in the 1st year, respectively. With the increase of decaying years, the activity of soil alkaline phosphatase increased first and then decreased. It peaked in the 6th year and showed a significant difference (P<0.05), but the activities of urease and sucrose in one year were significantly higher than those in others (P<0.05). The RDA analysis showed that the sequences of the major soil physical and chemical factors affecting soil microbial biomass and enzymes activities were as follows:available potassium>water content>C:N ratio>alkaline hydrolysable nitrogen>pH>available phosphorus>N:P ratio>C:P ratio. The main driving factors were soil available potassium and water content. The results of this study could provide an important theoretical basis for the study on soil carbon, nitrogen and phosphorus cycling in the desert ecosystem.