莱州湾南岸土壤盐碱程度与养分含量空间变异

Spatial Variability of Soil Salt-alkali and Nutrients Content in the South Coast of Laizhou Bay

【目的】探究莱州湾南岸土壤可溶性盐含量、pH值和养分的空间分布特征,为我国北方滨海盐渍土区脆弱生境生态保护与修复提供科学依据。【方法】以莱州湾南部海岸线以南30 km的区域为研究对象,基于3 km距离的网格化布点法采集313个样点0~20、20~40、40~60 cm深度的土壤样品,经室内测定结合地统计学原理与地理信息系统等方法,揭示不同土层可溶性盐含量、pH值及表层土壤各养分指标的空间变异性特征。【结果】1)研究区域0~20、20~40、40~60 cm土层可溶性盐含量分别介于0.19~8.44、0.14~9.86、0.18~10.61 g∙kg^(−1)之间,各土层平均土壤可溶性盐含量分别为1.23±1.65、1.42±1.73、1.48±1.72 g∙kg^(−1),盐渍化等级以非盐渍化土为主,盐渍化类型以硫酸盐−氯化物型及氯化物−硫酸盐型为主,土壤含盐量随土层深度增加而增加。各土层可溶性盐含量空间分布不均,0~20 cm土层土壤盐分呈中等程度的空间自相关性,20~40 cm和40~60 cm土层盐分空间自相关性较强。2)研究区域0~20、20~40、40~60 cm土层土壤pH值分别介于7.04~9.38、7.04~9.66、7.08~9.79之间,各土层平均土壤pH值分别为8.17±0.46、8.39±0.47和8.46±0.46,整体以非碱性等级为主;0~20 cm土层pH值呈中等程度的空间自相关特征,20~40 cm和40~60 cm土层pH值空间自相关性较强。3)研究区域表层土壤有机质、全磷和全钾含量介于0.28~30.29、0.20~1.29、15.44~23.01 g∙kg^(−1)之间,平均含量分别为9.70±6.50、0.59±0.21和19.21±1.31 g∙kg^(−1);有效氮和速效钾的含量介于1.33~66.72mg∙kg^(−1)和24.90~248.20 mg∙kg^(−1)之间,平均含量分别为12.67±9.62mg∙kg^(−1)和94.64±45.60 mg∙kg^(−1)。土壤有机质和速效钾含量呈由海到陆沿平行于海岸线的方向带状增加的分布趋势,空间自相关性较强。有效氮、全磷、全钾空间分布不均,呈中等程度的空间自相关特征。【结论】莱州湾南岸土壤盐碱程度和养分含量总体呈较低水平且空间分布不均,各指标空间变异在不同程度上受到结构性因素与随机性因素的共同影响,人为活动、土壤质地与植被生长状况是莱州湾南岸土壤盐碱与养分空间变异的主控因素。本研究可为我国陆地生态系统脆弱生境生态保护与精准修复、北方滨海盐渍土科学管理与利用、边际土地产能提升与固碳增汇等工作提供理论依据。

【Objective】The spatial variability distribution characteristics of soil soluble salt content,pH and nutrients in the southern coast of Laizhou Bay were explored to provide scientific basis for ecological protection and restoration of vulnerable habitats in coastal saline soil areas in northern China.【Method】The area 30 km south of the southern coastline of Laizhou Bay were selected as the research object,313 soil samples at depths of 0~20,20~40,and 40~60 cm were collected by the grid sampling method at a distance of 3 km.The spatial variability characteristics of total soluble salt content,pH in different soil layers and surface soil nutrient indexes were revealed by laboratory experimental determination and analysis,combined with geostatistics and geographic information systems.【Result】1)The soluble salt content of 0~20,20~40 and 40~60 cm soil layers in the study area were between 0.19~8.44,0.14~9.86 and 0.18~10.61 g∙kg^(−1),respectively.The average soil soluble salt content of each soil layer were 1.23±1.65,1.42±1.73 and 1.48±1.72 g∙kg^(−1),respectively.The main salinization grade was non-salinization.The main salinization type were sulfate-chloride type and chloride-sulfate type.The soil salt content increased with the increase of soil depth.The spatial distribution of total soluble salt content in each layer was uneven.The spatial autocorrelation of soil salinity in 0~20 cm soil layer was moderate,and the spatial autocorrelation of soil salinity in 20~40 cm and 40~60 cm soil layers was strong.2)The soil pH values of 0~20,20~40 and 40~60 cm soil layers in the study area were between 7.04~9.38,7.04~9.66 and 7.08~9.79,respectively.The average soil pH values of 0~20,20~40 and 40~60 cm in the study area were 8.17±0.46,8.39±0.47 and 8.46±0.46,respectively.The non-alkaline was the main grade.The pH value of 0~20 cm soil layer showed moderate spatial autocorrelation,and the pH value of 20~40 cm and 40~60 cm soil layers had strong spatial autocorrelation.3)The contents of organic matter,total phosphorus and total potassium in the surface soil of the study area were between 0.28~30.29,0.20~1.29 and 15.44~23.01 g·kg^(−1),and the average contents were 9.70±6.50,0.59±0.21 and 19.21±1.31 g·kg^(−1),respectively.The contents of available nitrogen and available potassium were between 1.33~66.72 and 24.90~248.20 mg·kg^(−1),and the average contents were 12.67±9.62 and 94.64±45.60 mg·kg^(−1),respectively.The content of soil organic matter and available potassium increased from sea to land along the direction parallel to the coastline,with strong spatial autocorrelation.The spatial distribution of available nitrogen,total phosphorus and total potassium was uneven,showing moderate spatial autocorrelation characteristics.【Conclusion】The soil salt-alkali and nutrients content in the southern coast of Laizhou Bay were generally low and the spatial distribution was uneven.The spatial variation of each index is affected by structural factors and random factors to varying degrees.Human activities,soil texture and vegetation growth were the main controlling factors of spatial variation of soil salt-alkali and nutrients in the southern coast of Laizhou Bay.This study can provide theoretical for the ecological protection and precise restoration of fragile habitats in China’s terrestrial ecosystem,the scientific management and utilization of coastal saline soil in the north of China,and the improvement of marginal land productivity and carbon sequestration.