小流域尺度土壤养分的空间分布特征及其与土地利用的关系

以四川省资阳市松涛镇的响水村小流域为研究背景,以地理信息系统为技术手段,研究了小流域尺度土壤养分的空间分布特征,并结合数理统计的分析方法,进一步探讨了土地利用对土壤养分的影响。结果表明:研究区域土壤表层养分含量均呈现较明显的空间分布格局,总趋势大都具有条带状和斑块状的特点,旱地、果园、裸地的土壤全氮、有机质普遍缺乏,特别是处于坡顶的裸地,应成为今后的控制重点,此外,旱地、果园的水溶态养分高值分布区也应给予高度重视。方差分析与均值比较表明:土地利用对全氮、有机质、全磷、水溶性磷含量都有显著影响(P<0.01),其影响程度为有机质>全氮>全磷>水溶性磷,而全钾、硝态氮则不受土地利用的显著影响,究其原因可能是紫色土钾素含量更倾向于土壤母质中所含矿物的控制,而土壤硝态氮的情况比较复杂,可能有更为重要的因素(如施肥、降雨、径流)制约着硝态氮的含量。

Spatial Distribution Feature of Soil Nutrient Contents from a Small Watershed and Their Relations to Land Use

Based on the application of GIS and traditional statistical methods, this paper studied the spatial distribution feature of soil nutrient contents and their relations to land use in a small watershed, which located in the Ziyang County, Sichuan Province. The results showed that soil total nitrogen and organic matter for the upland,orchard and bare land in interested area were widely deficient, especially for the bare land on the top and steep slope of hill. We should pay more attention to this kind of land use in the future. Moreover, the high value distribution areas for the soluble nutrients in the upland and orchard should also be more cared. And remarkable spatial distributions with the feature of stripe and patch were also found for all nutrients. The spatial heterogeneity of most soil nutrients except for total potassium and nitrate was significantly influenced by the land use. The rank of the influenced nutrients was as follows: organic matter>total nitrogen>total phosphorus> soluble phosphorus. Generally speaking, the total potassium with lesser coefficient of variability mainly inherited the quality of material rock. However, more important factors (e.g. fertilizer,rainfall and runoff) may control the content of nitrate, as a result, there no existed significant relationship between land use and nitrate.