艾比湖湿地不同厚度盐结皮与土壤物理性质的相互关系及其影响因素

The relationship between different salt crust thickness and soil physical properties in Ebinur Lake wetland and its influencing factors

为探讨艾比湖湿地土壤盐结皮与其覆盖下土壤物理特性的相互关系,采用野外调查与室内试验相结合的方法,在湿地内选取具有代表性的30个样点,对不同类型盐结皮覆盖下的土壤物理特性进行分析,并探讨其对盐结皮厚度的影响。结果表明:1)盐结皮衰退期和生长期覆盖下土壤粒度以1.00~0.05 mm为主,盐结皮成熟期覆盖下土壤粒度以0.01~0.001 mm为主。土壤容重由高到低依次为盐结皮生长期(1.81 g/cm^(3))、成熟期(1.58 g/cm^(3))和衰退期(1.34 g/cm^(3))。土壤孔隙度由盐结皮衰退期(50.8%)、成熟期(40.7%)到生长期(32.6%)逐渐下降。土壤含水量由高到低依次为盐结皮生长期(32.5 g/kg)、成熟期(21.7 g/kg)和衰退期(16.2g/kg)。土壤饱和含水量和土壤含水量由高到低依次为盐结皮衰退期、成熟期和生长期。2)盐结皮厚度与土壤物理性质相关性分析表明,盐结皮厚度与0~20 cm土壤的毛管孔隙度和土壤粒度(1.00~0.05 mm)显著正相关(P<0.01),与土壤容重呈负相关(P<0.05);而且随深度增加盐结皮厚度与土壤物理特性相关性逐渐降低。3)主成分分析表明:影响盐结皮厚度主要包括第一主成分(78.1%)土壤毛管孔隙度,第二主成分(16.5%)土壤粒度(0.01~0.001 mm)。孔隙度增大能够促进盐结皮产生和积累,使盐结皮越厚。土壤中粒度0.01~0.001mm含量增多,能抑制盐结皮产生和积累,使盐结皮越薄。总之一方面不同厚度盐结皮的覆盖会使土壤物理特性(含水量、孔隙度、粒度)发生变化,另一方面土壤物理特性会影响盐结皮厚度,两者相互作用相互影响。

To investigate the Ebinur lake wetland soil physical properties under salt crusts and their interactions,we selected representative samples of 30 sites from different areas in wetland and with different salt crust thickness,on the depth of 0-20 cm,20-40 cm,and 40-60 cm,analyzed the physical properties of soil,including porosity,particle size,and water content by combining field investigation and laboratory tests,and discussed the influences of properties on salt crust thickness.The results show that:1)The grain size of soil covered by salt crust is mainly in the range of 1.00-0.05 mm during the declining and the growing periods,while at the mature stage it is mainly in the range of 0.01-0.001 mm.The bulk density of soil is ranked from the highest one of the salt crust in the growing period(1.81 g/cm^(3)),to that of the mature period(1.58 g/cm^(3))and to the lowest one of that in the declining period(1.34 g/cm^(3)).The soil porosity decreases gradually from the declining period(50.8%),mature period(40.7%)to the growing period(32.6%).Soil moisture content from high to low is in the order of growing period(32.5 g/kg),mature period(21.7 g/kg),and the declining period(16.2 g/kg).Soil saturated water content and soil moisture content are in the order of the declining period,mature period,and the growing period from high to low.2)Salt crust thickness is significantly positively correlated with both capillary porosity and soil particle size in the range of 0.05-1 mm for soil in the depth of 0~20cm soil(P<0.01),while negatively correlated with soil bulk density(P<0.05).The correlation between salt crust thickness and soil physical properties gradually decreases with the increase of depth.3)The factors influencing salt crust thickness mainly include the capillary porosity as the first principal component(78.1%)and the soil particle size as the second principal component(16.5%).The increase of porosity can promote the formation and accumulation of salt crust,and make the salt crust thicker,while the increase of grains in the size of 0.001 to 0.01 mm can inhibit the formation and accumulation of salt crust,and make salt crust thinner.Overall,salt crust changes the physical characteristics of soil(water content,porosity,and grain size);on the other hand,the physical properties of soil affect the thickness of salt crust.