建三江地区土壤氮磷生态化学计量空间异质性特征及其影响因素分析

土壤全氮(TN)、全磷(TP)及氮磷比(N/P)是衡量土壤肥力和土壤质量的重要指标,研究其空间异质性特征对土壤养分管理以及生态环境监测等政策的制订具有重要意义。本文通过土样采集和室内实验分析,结合地统计分析及地理信息系统(GIS)等方法,对建三江地区表层(0~20 cm)土壤中的氮、磷生态化学计量空间变异及影响因素进行研究。结果表明:土壤全氮、全磷以及氮磷比的均值分别为2.49×10-3、0.81×10-3和3.20。土壤全氮和氮磷比空间自相关性很强,而土壤全磷空间自相关性处于中等程度,且均符合指数模型。从空间分布来看,土壤全氮高值区主要呈斑块零星分散在东部、南部和西北地区,而低值区主要在西北和中西部地区零星分布;土壤全磷高值区主要分布在东部和西北地区,中部地区则为低值地区;土壤氮磷比分布则呈镶嵌状,高值区以斑块状分散于中部、南部和东北部地区,而低值区主要位于西北地区。研究区土壤类型、第四系类型和土地利用类型是影响土壤氮、磷生态化学计量特征的重要结构性和随机性因素,而土壤母质和地貌类型则对土壤氮、磷生态化学计量特征影响不大。

Spatial heterogeneity and influencing factors of the ecological stoichiometry of soil nitrogen and phosphorus in the Jiansanjiang area

The total nitrogen (TN), total phosphorus (TP), and nitrogen/phosphorus ratio (N/P) of soil are important indicators of soil fertility and quality. The study of their spatial heterogeneity is of great significance for the formulation of policies concerning soil nutrient management and ecological environment monitoring. Using methods such as geostatistical analysis and geographic information system (GIS), this study analyzed the spatial variation and influencing factors for the ecological stoichiometry of nitrogen and phosphorus in the surface soil (depth: 0~20 cm) of the Jiansanjiang area through soil sampling and laboratory tests. The results are as follows. The soil in the study area has average TN, TP, and N/P of 2.49×10-3, 0.81×10-3, and 3.20, respectively. The TN and N/P of the soil have high spatial autocorrelations, while the TP of the soil has a moderate spatial autocorrelation, all in line with the index model. Regarding the spatial distribution, zones with high TN content are mainly scattered in the form of patches in the east, south, and northwest of the Jiansanjiang area, while zones with low TN content are mainly scattered in the northwestern, central, and western portions of the area. Zones with high TP content are mainly distributed in the east and northwest, while zones with low TP content are in the central portion. Moreover, the N/P ratio is distributed in a mosaic-like pattern. Specifically, zones with high N/P ratios are distributed in the form of patches in the central, southern, and northeastern portions, while zones with low high N/P ratios are mainly distributed in the northwest. The types of the soil, the Quaternary, and land uses of the study area are important structural and random factors affecting the ecological stoichiometric characteristics of soil nitrogen and phosphorus, while the types of the soil parent materials and landforms have little effect on these characteristics.