东平湖湿地土壤不同形态无机硫含量及其时空分布特征

  目的  了解东平湖湿地土壤不同形态无机硫含量水平与分布特征。  方法  采集东平湖湿地表层土壤样品（0 ~ 5 cm）和不同植被区（芦苇区、菹草区、植被混生区和对照区）土壤柱样（0 ~ 10 cm），分析样品中总无机硫（TIS）及其各形态（水溶性硫、吸附性硫、盐酸溶解性硫及盐酸挥发性硫）的含量，探讨了不同形态无机硫含量的时空分布特征及其影响因子。  结果  东平湖湿地表层土壤总无机硫含量范围为31.26 ~ 117.36 mg kg?1，均值为75.85 mg kg?1；各形态的平均含量占比为水溶性硫（43.49%）> 盐酸溶解性硫（27.37%）> 吸附性硫（26.78%）> 盐酸挥发性硫（2.36%）；其含量的空间分布总体表现为湖区码头附近显著升高，大汶河入湖口较低。柱状土壤总无机硫、水溶性硫、吸附性硫与盐酸溶解性硫含量总体表现为夏季和芦苇区最高，且随土层深度的增加逐渐降低；菹草区总无机硫、吸附性硫、盐酸溶解性硫由于受季节与植被区的交互作用影响而无显著季节变化。表层土壤和柱状土壤不同形态无机硫含量间存在一定的正相关关系，且与有机质多呈显著正相关；柱状土壤中各形态无机硫含量（除盐酸挥发性硫外）与pH显著正相关，而与Eh显著负相关。  结论  东平湖湿地土壤不同形态无机硫的时空分布主要受到人类活动、植被分布和水动力条件的影响，且土壤有机质、温度、pH和Eh为其关键影响因子。

Forms and Distribution Characteristics of Inorganic Sulfur in Soils of Dongping Lake Wetland

  Objective  The aim is to understand the speciation content and distribution characteristics of inorganic sulfur (S) in Dongping Lake Wetland.  Method  Twenty soil surface samples (0 - 5 cm) were collected around Dongping Lake, and soil column samples (0 - 10 cm) were also collected in different seasons from vegetable areas (reed area, Potamogeton crispus area, mixed vegetation area and control area with no vegetation). The contents of inorganic S in different forms which according to the order of extraction are H₂O-S (HS), Adsorbed-S (AS), HCl-Soluble-S (HSS) and HCl-Volatile-S (HVS) were analyzed. Furthermore, the spatial distribution characteristics and its influencing factors were discussed.   Result  The results showed that the content of total inorganic S (TIS) in the surface soils of Dongping Lake Wetland ranged from 31.26 mg kg?1 to 117.36 mg kg?1 with the mean value of 75.85 mg kg?1, and the average proportions of the inorganic S speciation contents were in the order of HS (43.49%) > HSS (27.37%) > AS (26.78%) > HVS (2.36%). The spatial distribution of inorganic S speciation contents in surface soils showed that they were generally significantly higher near the wharves of the lake area but were lower at the entrance of the Dawen River. The contents of TIS, HS, AS and HSS in the columnar soils were significantly different in vegetation areas, depths and seasons. Specifically, the inorganic S speciation contents were the highest in summer and in reed area, and the contents decreased with the increase of depth. Nevertheless, the TIS, AS and HSS contents in the Potamogeton crispus area had no significant seasonal change due to the influence of the interaction effect. Some forms of inorganic S in the surface and columnar soils were significantly positively correlated with each other, and there were generally significant positive correlations between the inorganic S forms and organic matter. Besides, the inorganic S forms except HVS in columnar soils were also positively correlated with soil pH but negatively correlated with soil Eh.   Conclusion  The spatial distribution of soil inorganic S in Dongping Lake wetland was mainly affected by human activities, vegetation distribution and hydrodynamic conditions; and soil organic matter, temperature, soil pH and Eh were the key influencing factors.