黄河三角洲不同地表覆被类型和微地貌的土壤盐分空间分布

Spatial distribution of soil salinity under different surface land cover types and micro-topography in the Yellow River Delta

掌握不同地表覆被类型和微地貌特征下的不同深度土壤盐分空间分布规律,对土壤盐渍化防治具有重要意义。该研究以黄河三角洲入海口为研究区,在分析不同深度土壤全盐量、盐基离子(Ca^2+、Mg^2+、Na^+、SO4^2-、HCO3^-、Cl^-)空间变异特征的基础上,通过单因素方差分析不同地表覆被类型和微地貌特征下该区土壤盐分的差异,并通过地理探测器分析地表覆被类型、微地貌对土壤盐分的交互影响。结果表明:1)表层土壤Mg2+变异系数达到1.0108,为强变异性,其余盐基离子均为中等变异性,且均有强烈的空间相关性,全盐量与盐基离子均呈现沿海向内陆降低的趋势,约有42.57%的地区为轻度盐化土;2)不同地表覆被类型间土壤全盐量与Na^+、Cl^-具有显著差异;3)不同微地貌类型间Na^+、Cl^-具有显著差异;不同海拔的深层土壤Na^+具有显著差异;4)海拔对土壤全盐量与Na^+的解释力最强,地表覆被类型对土壤Cl^-的解释力最强;5)坡向和海拔对土壤盐分的交互作用最强烈,地理探测器q值在0.545~0.708之间,其次是地表覆被类型与坡向,q值在0.521~0.613之间。氯化钠主导该区域土壤盐分空间变异,不同地表覆被类型和微地貌特征下均呈显著差异,表层土壤盐分明显高于深层,坡向与海拔之间的交互作用能够较好地解释该地区土壤盐分空间分布。

Strong seawater immersion usually determines the formation of the Yellow River Delta and the land-making process of the Yellow River.The soil is generally rich in soluble salt,due to the groundwater is highly mineralized during the formation process.The salinization situation can deteriorate into full-scale ecological system in recent years.It is necessary to analyze the distribution characteristics of soil salinity in this area,further to clarify influence factors,such as surface cover types and landform features,in order to effectively control soil salinization,and prevent potential salinization as the chemical elements increased in soil.Taking the Yellow River Delta estuary as the research area,this study aims to analyze the spatial variation characteristics of total soil salt content and base ions(Ca^2+,Mg^2+,Na^+,SO4^2-,HCO3^-,Cl^-)using various geostatistical methods,such as the Kriging interpolation method.A single-factor analysis of variance was used to calculate the differences in soil salinity in the area under different surface cover types and micro-landform features.Geodetectors were also used to explore the interaction effect between the soil salinity and some parameters,including the land cover type,landform type,slope,landscape,and altitude in the area.The results show that the coefficient of variation of surface soil Mg^2+reached 1.0108,indicating a strong variability.The rest of base ions indicated a medium variability with a strong spatial correlation.There was a decrease from coastal to inland for both the total salt content and base ions.About 42.57%area was slightly saline soil,whereas,only 0.51%was moderately saline soil.The total salt content in soil was significantly different from the content of Na^+ and Cl^- among different surface cover types.The single-factor ANOVA results demonstrated that the content of Na^+ and Cl^- in the surface and deep soil reached 0.00,indicating a very significant difference,whereas,the total salt content of surface soil was 0.01,reaching a very significant difference,and the total salt content of deep soil was 0.028 to reach a significant difference.There were significant differences in the content of Na+and Cl-between different types of micro-landscape.The results of single-factor analysis of variance for Na+in the surface and deep soils were both 0.002,reaching a very significant difference,while the analysis of Cl^- in the deep soil was 0.039,reaching a significant level of difference.The deep soils at different altitudes have significant differences in Na^+.The altitude has the strongest explanatory power for total soil salinity and Na+,and the surface cover types have the strongest explanatory power for soil Cl^-.The slope direction and altitude have the strongest effect.The interaction of soil salinity was the strongest,where the q value was between 0.545 and 0.708,followed by the surface cover type and slope aspect,where and the q value was between 0.521 and 0.613.Both types of interaction can be used to better explain the change characteristics of soil salt.Therefore,the characteristics of soil salinity can be served as an indicator for the types of surface cover and micro-topography,while these factors,including the altitude,slope direction,and types of surface cover,can also pose a strong impact on the soil salinization under the interaction.