绿洲化对土壤养分及化学计量特征的影响

为了阐明绿洲化过程中土壤养分含量及土壤碳氮磷生态化学计量值的动态变化特征，以乌兰布和沙漠东北部绿洲为研究对象，通过24 a的定位监测，分析了土壤有机碳（SOC）、全氮（TN）、全磷（TP）、碱解氮（AN）、速效磷（AP）及土壤C，N，P生态化学计量的动态变化特征。结果表明:（1）研究区土壤总体贫瘠，养分含量整体水平不高。但是随着绿洲建设时间的延长，土壤养分含量呈显著的线性增加趋势。（2）绿洲化过程中，土壤C:N，C:P，N:P，AN:AP的变化趋势总体上呈现先增大后减小的趋势，但是达到最大值的时间各不相同。（3）土壤C，N，P元素化学计量值与C，N，P元素之间的最优拟合关系显示C:N，C:P主要受SOC影响，N:P主要受N影响，表明SOC和N含量决定了研究区土壤中C，N，P化学计量特征的变化过程。

Soil Nutrient and Stoichiometry Characteristics in Process of Oasisization in the Ulan Buh Desert Oasis,Inner Mongolia

Ecological stoichiometry is the study of the balance of multiple chemical elements in ecological interactions, it is the important points and hotspot in ecology research. To illustrate the dynamic changes of soil ecological stoichiometry characteristics and soil carbon, nitrogen, phosphorus in the process of oasisization, a field study was conducted over a period of 24 years in Ulan Buh Desert Oasis, northwestern China. And the contents of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP) were investigated. The results showed as follows. (1) The soil fertility of research area was at the low level. But with the extension of oasis construction time, soil nutrient contents showed the extremely remarkable linear increasing trend. (2) The trend of soil C:N, C:P, N:P and AN:AP showed the increasing trend first and then decreasing trend. Nevertheless, the time to reach the maximum was different in the process of oasisization. (3) The optimal fitting relationship between the soil nutrients and their stoichiometric ratios showed that C:N and C:P were dominated by C, and N:P was dominated by N, indicating that SOC and N contents determine the changing process of C, N and P stoichiometric characteristics in the studied area.