岩溶区土壤理化特征与土壤有机碳含量关系研究

Study on the Relationship Between Soil Physical and Chemical Characteristics and Soil Organic Carbon Content in Karst Area

为研究不同土地利用类型下土壤有机碳(SOC)的分布特征和时空差异,文章以贵州绥阳双河国家地质公园典型喀斯特土壤剖面为研究对象,通过雨季和旱季对6种不同土地利用类型土壤表层、20 cm、40 cm、60 cm进行土壤样品的采集,运用野外调查和室内分析的方法,探讨不同土地利用类型下土壤剖面理化性质与土壤有机碳含量及其相互间的耦合关系。结果表明:土壤有机碳含量雨季明显高于旱季,随着土层深度的增加,各用地类型下土壤有机碳含量普遍下降。不同土地利用类型的土壤有机碳含量变化规律为有林地(124690 mg/kg)>退耕还林地(104430 mg/kg)>灌丛地(81460 mg/kg)>旱地(77530 mg/kg)>灌草地(54110 mg/kg)>撂荒地(46530 mg/kg)。对各土地利用类型SOC与土壤理化性质进行相关性及因子分析发现,土壤含水量、土壤温度与SOC的相关性较其他因子偏高且呈现正相关,而土壤有机碳含量与土壤pH值、土壤容重、土壤孔隙度的相关性为负相关,影响研究区土壤有机碳含量的主要因素是土壤含水量(41.268%),其次是土壤温度(28.038%)。土壤理化性质在不同程度上影响着研究区的土壤有机碳含量,而土壤有机碳含量的变化又会对该区域的土壤理化性质有着明显的调节作用,两者相互联系并且相互影响,共同制约着喀斯特地区土壤在生态系统中的演变。

To study the distribution characteristics and temporal and spatial differences of soil organic carbon(SOC)under different land use types,taking the typical karst soil profile of Shuanghe National Geopark in Suiyang,Guizhou as the research object,through the rainy and dry seasons,soil samples of 6 different land use types,20 cm,40 cm,and 60 cm were collected,using the methods of field investigation and indoor analysis,explore the physical and chemical properties of soil profile and soil organic carbon content and their coupling relationship under different land use types.The results showed that the content of soil organic carbon in the rainy season was significantly higher than that in the dry season.As the depth of the soil layer increased,the soil organic carbon content under all types of land generally decreased.The change law of soil organic carbon content of different land use types is forest land(124690 mg/kg)>returning farmland to forest(104430 mg/kg)>shrubland(81460 mg/kg)>dry land(77530 mg/kg)>shrubland(54110 mg/kg)>abandoned land(46530 mg/kg).Correlation and factor analysis of SOC and soil physical and chemical properties of each land use type found that the correlation between soil water content,soil temperature and SOC was higher than other factors and showed a positive correlation,while the correlation between the content of soil organic carbon and soil pH,soil bulk density and soil porosity is negative.The main factor affecting the soil organic carbon content in the study area is soil water content(41.268%),followed by soil temperature(28.038%).The physical and chemical properties of soil affect the soil organic carbon content in the study area to varying degrees,and the changes in soil organic carbon content will have a significant regulatory effect on the soil physical and chemical properties in the area.The two are interrelated and affect each other,and jointly restrict the evolution of soil in the ecosystem of karst areas.