研究土壤有机碳密度的影响因素,对调节气候变化、农业可持续发展等具有重要意义.以安徽省为例,估算0～10 cm、10～20 cm、20～30 cm 和 30～100 cm 土层的土壤有机碳密度(soil organic carbon density,SOCD),运用结构方程模型分析气候、地形、植被、土壤含水量、人类活动等环境因子对SOCD的影响.结果表明:①在0～30 cm 土层中SOCD呈现逐渐降低的趋势,0～10 cm、10～20 cm 和 20～30 cm 3 个土层的 SOCD 平均值分别为 2.09、1.63 和 1.10 kg/m2;30～100 cm 土层的SOCD平均值为4.46 kg/m2;②全省土壤有机碳密度空间分布呈自北向南方向逐渐增长趋势.0～10 cm和10～20 cm 土层SOCD高于5.00 kg/m2的区域主要分布在江淮丘陵区和沿江平原区;20～30 cm 土层SOCD高于3.00 kg/m2的区域呈点状分布在皖南丘陵山区;30～100 cm SOCD的高值主要分布在皖南山地丘陵区;③在0～10 cm、10～20 cm和20～30 cm 土层的结构方程模型中,土地利用对SOCD的正向影响最大,影响系数分别为0.22、0.20、0.22,年均温对SOCD的负向影响最大,影响系数为-0.04、-0.03、-0.03.30～100 cm 土层中受到年降雨量的影响最大,但土地利用和归一化植被指数(normalized differ-ence vegetation index,NDVI)的影响并不显著(p＞0.05).地形通过土地利用、NDVI、年降水量和年均温4个路径影响SOCD.人类足迹通过NDVI影响SOCD,对NDVI的影响达到极显著水平(p＜0.001).本研究构建的结构方程模型初步说明了不同环境因子之间的关系,对SOCD的调节和农业可持续发展提供了理论依据.
Analysis of Factors Affecting Soil Organic Carbon Density in Anhui Province Based on Structural Equation Modelling
Research on the factors affecting soil organic carbon density is of great significance for regulating climate change and sustain-able agricultural development.Previous studies have mainly explored the relationship between various factors(e.g.,climate,altitude,soil physicochemical properties,etc.)and the influence of soil organic carbon density,but less involved in the interaction relationship between factors.Typical soil profiles were collected in Anhui Province to estimate the soil organic carbon density(SOCD)in the 0～10 cm,10～20 cm,20～30 cm and 30～100 cm soil horizons.The structural equation model was used to analyze the effects of climate,elevation,vegeta-tion,soil water content,human activities and other environmental factors on SOCD.The results are as follows.In the 0～30 cm soil layer,SOCD show a gradually decreasing trend,and the average SOCD in the 0～10 cm,10～20 cm and 20～30 cm soil layers were 2.09,1.63 and 1.10 kg/m2,respectively.The average SOCD of 30～100 cm soil layer is 4.46 kg/m2.The spatial distribution of SOCD in the province grad-ually increased from north to south.The SOCD of 0～10 cm and 10～20 cm soil layer is higher than 5.00 kg/m-2,mainly distributed in the Jianghuai hilly downland and the Riverine Plain.The areas with SOCD higher than 3.00 kg/m2 in the 20～30 cm soil layer were distributed in the South Anhui hilly region.The high SOCD values of 30～100 cm are mainly distributed in the South Anhui hilly region.In the structur-al equation model of 0～10 cm,10～20 cm and 20～30 cm soil layer,land use has the largest positive influence on SOCD,and the influence coefficients are 0.22,0.20 and 0.22,respectively.The average annual temperature has the largest negative influence on SOCD,and the in-fluence coefficients are-0.04 and-0.03.Annual rainfall was the most significant in 30～100 cm soil layer,but land use and NDVI were not significantly affected(p＞0.05).Topography affects SOCD through four paths:land use,NDVI,annual precipitation and average annual temperature.Human footprint affected SOCD through NDVI,and the effect on NDVI reached a very significant level(p＜0.001).The struc-tural equation model established in this study initially explained the relationship between different environmental factors,and provid a theoret-ical basis for SOCD regulation and agricultural sustainable development.
soil organic carbon densitystructural equation modelspatial distributioninfluence factorsAnhui Province
万方数据
维普
