柴河流域典型景观类型土壤氮磷含量的空间变异特征

摘要

In order to understand spatial variability characteristics of soil nitrogen and phosphorus contents in the typical landscape units in Chaihe catchment, 72 surface soil samples were collected from the lands different in landscape and land-use types in Chaihe catchment. The contents of nitrogen, phosphorus, and organic matter of the soils were analyzed. Results showed that the soils in phosphorus mining area and forests of phosphorus-enriched area contained the higher phosphorus. The average contents of total phosphorus and available phosphorus were 20 g/kg and 3 687.7 mg/kg, respectively. The soils in sediments of ditches and Chaihe River contained the higher nitrogen. The average contents of total nitrogen and available nitrogen reached 2.99 g/kg and 631.8 mg/kg, respectively. The great variation of the contents of soil nitrogen and phosphorus were found in different land-use types in phosphorus mining area, slope farmland, and flatland. The results of nested ANOVA analysis of soil nutrient contents suggested that landscape, land-use and land spatial location co-determine the variability of soil nitrogen, phosphorus and organic matter contents in the catchment. It is, therefore, necessary to combine landscape with land-use and land spatial location together in risk assessment and control of non-point source pollution in Chaihe catchment.%为了从流域尺度了解柴河流域土壤氮、磷含量的空间变异特征，在柴河流域选择6个景观类型，并根据每个景观类型内不同土地利用方式及景观位置，共进行了72个样点的表层土壤采集，并对土壤有机质、氮、磷含量进行了测定。结果表明，磷素主要以磷矿区及富磷区林地区域含量较高，其中磷矿区土壤全磷含量平均高达20 g/kg，富磷区林地有效磷含量平均为3687.7 mg/kg；而氮素则表现为沟渠和柴河河道底泥的含量较高，柴河底泥中全氮及碱解氮含量高达2.99 g/kg和631.8 mg/kg。相同景观类型下不同土地利用方式土壤氮磷含量在富磷区、坡耕地及坝平地均表现出较高的差异。嵌套方差分析表明景观类型及土地利用方式或所处的景观位置对土壤有机质及氮磷含量均具有显著的影响。以上结果表明柴河流域内土壤养分含量空间变异程度较高，不同景观类型和土地利用方式共同决定了土壤氮磷含量的变异。因此，在面源污染输移风险评估及防控时应同时结合景观类型及土地利用类型进行分析，并在此基础上探讨主要影响因素。