贵州表层土壤有机质空间变异特征及其影响因素分析

Spatial Variation of Surface Soil Organic Matter and Its Influencing Factors in Guizhou Province

为探究贵州表层土壤有机质的空间变异特征及其主要影响因素,使用贵州省第二次土壤普查资料中193个土壤剖面数据,结合贵州省气象资料、土地利用类型图及土壤类型图等资料,运用地统计学和多元回归分析各因素对表层土壤有机质空间变异的解释能力。结果表明:(1)贵州省表层土壤有机质含量范围为0.05%~36.68%,平均含量为5.23%±4.96%,变异系数为94.90%;(2)表层土壤有机质在空间分布上表现出东北部高,西南部较低的格局;(3)半变异函数分析表明,贵州省土壤有机质主要受自然因素影响,海拔、CEC、耕作方式和土壤质地对表层土壤有机质含量变异的综合解释能力为35.9%,海拔作为最重要的影响因素能独立解释其变异的25.6%,CEC和耕作方式分别能解释11.3%,7.4%。贵州表层土壤有机质与年均气温呈负相关关系,与海拔呈正相关关系。研究区表层土壤有机质的分布与碳酸盐岩分布面积比例存在相关关系,整体上,随着喀斯特分布面积比例增大而受自然因素影响增大。喀斯特分布面积比例为0~10%区域主要受农业耕作施肥等人类活动的影响,11%~30%区域主要受海拔影响,31%~50%区域受年均温和CEC影响,51%~100%区域受到海拔、年均温、降水、CEC和pH等自然因素的综合影响更大。研究结果有助于定量化认识贵州的土壤有机质空间分布,为该地区土壤肥力调控和生态管理提供科学依据和资料参考。

In order to study the spatial variability of soil organic matter and its main influencing factors,193 soil profiles from the second soil survey in Guizhou province were used,based on the meteorological data,land use type map and soil type map of Guizhou province,geostatistics and multiple regression were used to analyze the explanatory ability of each factor to the spatial variability of topsoil organic matter.The results showed that:(1)The organic matter content of surface soil in Guizhou Province ranged from 0.05% to 36.68%,with an average of 5.23%±4.96% and a coefficient of variation of 94.90%.(2)The spatial distribution of topsoil organic matter was higher in the northeast and lower in the southwest.(3)According to the results of semi-variational function analysis,soil organic matter in Guizhou province was mainly affected by natural factors.The comprehensive explanatory ability of altitude,CEC,tillage and soil texture for the variation of organic matter content was 35.9%,and altitude,as the most important influencing factor,could independently explain 25.6% of the variation.CEC and farming methods could explain 11.3% and 7.4%,respectively.There was a negative correlation between surface soil organic matter and average annual temperature and a positive correlation between surface soil organic matter and altitude.There was a correlation between the distribution of surface soil organic matter and the distribution area proportion of carbonate rocks in the study area.On the whole,the distribution area proportion of karst increased with the influence of natural factors.The areas with 0~10% karst distribution area were mainly affected by human activities such as agricultural cultivation and fertilization,11%~30% were mainly affected by altitude,31%~50% were mainly affected by average annual temperature and CEC,and 51%~100% of the areas were more affected by elevation,average annual temperature,precipitation,CEC and pH.The results are helpful to understand quantitatively the spatial distribution of organic matter in Guizhou,and provide scientific basis and reference for soil fertility regulation and ecological management.