黄河三角洲湿地土壤质量综合评价

Comprehensive Assessment of Soil Quality of Wetlands in the Yellow River Delta

将山东黄河三角洲国家级自然保护区湿地分为新生湿地、退化湿地、天然稳定湿地和耕作区湿地。采用土壤质量指数法,利用GIS技术,对黄河三角洲湿地土壤质量进行综合评价及土壤质量分区。结果可见,湿地土壤质量总体较低,土壤有机质和全氮含量平均值分别低于全国第二次土壤普查养分的分级标准6 g/kg和0.5g/kg,属于最差等级。土壤盐度和有效磷含量空间变异性很高(变异系数>100%)。从14个土壤理化指标中筛选出全磷含量、全氮含量、盐度、铵态氮含量和全硫含量,构成最小数据集,用于计算土壤质量综合指数;耕作区湿地的土壤质量最高,新生湿地和天然稳定湿地土壤质量居中,退化湿地土壤质量最差。基于克里金(Kriging)空间插值,将研究区湿地的土壤质量分为4个区域,结果与4种湿地类型的分布基本一致。对于新生湿地,2012年的土壤质量综合指数高于2007年,表明土壤质量明显提升。

The studied wetlands in the Yellow River Delta National Nature Reserve could be classified into newly-formed wetlands, degraded wetlands, natural stable wetlands and reclaimed regions wetlands according to the formation conditions of wetlands and the intensity of anthropogenic disturbances. Synthetic assessment and zonation of wetland soil quality in the Yellow River Delta were studied using soil quality index(SQI)method and GIS technology. Our results showed that the soil quality level was generally low with severe deficiency of soil organic matter(SOM) and soil total nitrogen(TN) based on Chinese 2nd national soil census.Soil salt and available phosphorus(AP) contents has shown a high spatial variations with the coefficient of variation of 100%.The minimum data set(MDS) consisted of total phosphorus(TP), total nitrogen(TN), soil salt content, ammonium nitrogen and total sulfur(TS) screening from fourteen soil indicators, which was used to calcualte SQI. The wetlands in reclaimed regions had the highest SQI value compared with other three wetlands, this was associated with strong human interference such as leakage fertilizer and improvement of nitrogen, followed by newly-formed wetlands and stable natural wetlands, whereas the soil quality of degraded wetland was worst due to high salinity.The area could be divided into four sub-regions based on the result of Kriging interpolation, which was consistent with the distribution of four wetland types. Compared with 2007,soil quality index for newly-formed wetlands in 2012 has significantly increased, indicating that soil quality has been greatly improved.