南方红壤区不同侵蚀程度下耕地土壤有效磷空间 分布特征及其驱动因素

以江西省兴国县耕地土壤有效磷为研究对象,结合高程、坡度、成土母质、土壤质地、耕层厚度和地貌类型等因素,运用Spearman相关性分析、回归分析和普通克里格法,对不同侵蚀程度下土壤有效磷空间变异及其驱动因素进行研究。结果表明:随着侵蚀程度的加深,土壤有效磷均值呈下降趋势,当侵蚀程度不断加重时,土壤有效磷均值又呈上升趋势。不同侵蚀程度下土壤有效磷含量差异显著(P0.001)。变异系数由大到小依次为极强度侵蚀(35.20%)剧烈侵蚀(28.09%)轻微侵蚀(28.02%)重度侵蚀(27.90%)无明显侵蚀(25.96%)中度侵蚀(25.78%)。在无明显侵蚀时,成土母质能独立解释1.7%的土壤有效磷空间变异。在轻微侵蚀、中度侵蚀和重度侵蚀时,高程的独立解释能力分别为5.7%、2.3%和2.9%。在极强度侵蚀时,成土母质的独立解释能力为5.0%。在剧烈侵蚀时高程的独立解释能力为1.9%。因此,高程和成土母质是不同侵蚀程度下土壤有效磷空间变异的驱动因素。研究成果为不同侵蚀程度下合理开展耕地利用和水土保持工作提供了参考。

Spatial Distribution of Soil Available Phosphorus and Its Driving Factors Under Different Erosion Degrees in South China

The spatial variation and the driving factors of soil available phosphorus (AP) of farmlands in Xinguo County under different erosion levels were analyzed by using the methods of Spearman correlation analysis, regression analysis and ordinary kriging combined with elevation, slope, parent material, soil texture, topsoil thickness and landform type. The results showed that the average AP decreased first and then increased with the increase of soil erosion level. Significant differences were found between AP under different soil erosion degrees (P<0.001), the coefficient of variation decreased in the order as extremely intensive erosion (35.20%) > severe erosion (28.09%) > slight erosion (28.02%) > serious erosion (27.90%) > unobvious erosion (25.96%) > moderate erosion (25.78%). In the case of unobvious erosion, parent material could explain 1.7% of spatial variability of AP. In the cases of slight, moderate and serious erosion, elevation could explain 5.7%, 2.3% and 2.9% of spatial variability of AP, respectively. In the case of the extremely intensive erosion, parent material could explain 5.0% of the spatial variability characteristics of AP. In the case of severe erosion, elevation could explain 1.9% of the spatial variability characteristics of AP. Thus, parent material and elevation are the main driving factors in controlling the spatial distribution of AP. The study results could provide references for the rational use of farmlands and for soil and water conservation under different erosion degrees.