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以辽河口滨海湿地不同盐分土壤为研究对象,采用室内密闭培养法研究了盐分与土壤有机碳矿化的关系。结果表明,不同样点间土壤电导率(EC1∶5)差异显著。74 d的培养期间,不同盐分土壤表层(0~10 cm)和下层(10~20 cm)的累积矿化量分别为6.54和2.79 g C·kg-1。根据一级动力学拟合结果,相应的有机碳潜在矿化势(C0)和矿化系数(k)分别为14.5、3.84 g C·kg-1和0.009、0.017 d-1。表层土壤的C0值高于下层土壤,且C0值在不同样点间差异显著。不同盐分土壤C0值与EC1:5、有机碳(SOC)、全氮(TN)、Ca2+、Mg2+、Cl-含量之间呈显著正相关,而k值与上述指标呈显著负相关。逐步回归分析表明,供试土壤的C0值更多地受Cl-和SOC的限制,而k值主要受SOC的限制。研究表明,盐分和土壤有机质性质的协同效应对辽河口滨海湿地不同盐分土壤有机碳的矿化具有重要作用。
Taking saline soil of Liaohe Estuary wetland as research object, the relationship between salinity and organic carbon mineralization was studied by indoor airtight culture method. The results showed that soil conductivity (EC1: 5) was significantly different among different sample sites. During 74 days of incubation, the cumulative mineralization of soil layers (0-10 cm) and lower layer (10-20 cm) were 6.54 and 2.79 g C kg-1, respectively. According to the results of the first-order kinetics fitting, the potential mineral potential (C0) and mineralization coefficient (k) of the corresponding organic carbon are 14.5, 3.84 g C · kg-1 and 0.009,0.017 d-1, respectively. The C0 value of the surface soil was higher than that of the lower soil, and the C0 value was significantly different among different sampling sites. There were significant positive correlations between C0 values and EC1: 5, organic carbon (SOC), total nitrogen (TN), Ca2 +, Mg2 + and Cl- contents in different salinity soils, while k value was negatively correlated with the above indexes. Stepwise regression analysis showed that C0 values in the soils were more limited by Cl- and SOC, while k values were mainly limited by SOC. The results show that the synergistic effect of salinity and soil organic matter plays an important role in the mineralization of organic carbon in different salt soils in the Liaohe Estuary wetland.