基于多元分析的岷江下游土壤有机碳密度空间分布及影响因素研究

Spatial Distribution and Its Influence Factors of Soil Organic Carbon Density of Lower Reaches of Minjiang River Based on Multivariate Analysis Method

采用传统统计、灰色关联度、逐步回归和通径分析相结合的多元分析方法对岷江下游1 138个样点的表层（0~20 cm）土壤有机碳密度及其影响因素进行研究。结果表明,该区表层土壤有机碳密度在0.89~6.49 kg/m2之间,均值为3.24 kg/m2。其在空间上呈不规则的斑块状分布,具中等空间相关性,表现出中部浅丘区高而西北和东部高丘区低的分布趋势。土地利用类型、土壤酸碱度（p H）、成土母质、地貌类型、坡度和土壤质地均是影响土壤有机碳密度的主要因素。其中,土地利用类型、p H、地貌类型、坡度和土壤质地与有机碳密度呈极显著相关。灰色关联度的分析表明与土壤有机碳密度关联最为密切的是地貌类型,其次是p H和成土母质,逐步回归和通径分析的结果均表明地貌类型是最主要因素,成土母质和p H次之。综合比较以上方法,得出地貌类型、成土母质和p H为影响岷江下游研究区表层土壤有机碳密度的主要因素。

Spatial distribution and its influence factors of topsoil（0–20 cm） organic carbon density（SOCD） of the Lower Reaches of Minjiang River were studied by the combination of traditional statistical analysis, gray related analysis, stepwise regression analysis and path analysis. SOCD ranged from 0.89 to 6.49 kg/m2 with a mean value of 3.24 kg/m2. Its overall distribution displayed irregular plaque-shaped, with a moderate spatial correlation, and SOCD was higher in the central low hilly than northeastern and eastern high hilly area. Among the influence factors, it showed extremely significant correlations with the land use, soil p H, topography, slope gradient and soil texture. Gray related analysis indicated that the highest correlation degree of SOCD with terrain, and followed by soil p H and soil parent material. Stepwise regression analysis combined with path analysis showed that terrain was the most significant influence factor, followed by soil parent material and p H. Therefore, terrain, soil parent material and p H were the main influence factors of topsoil organic carbon density in the lower reaches of Minjiang River.