北京山区土壤养分空间变化特征研究

Spatial Distributions of Soil Nutrients in Beijing Mountainous Area

为了揭示土壤养分空间变异分布特征并且指导土壤规划管理,以北京市西部山区水源林和京津风沙源地带为研究对象,在野外大田采集样本的基础之上,运用了地统计学与GIS相结合的研究方法,探究了典型区域土壤碱解氮、有效磷、速效钾、有机质和全氮的空间变化格局,同时采用模糊模式识别理论对土壤养分等级进行了综合评价,并结合地区的实际情况分析了其变异特性的影响因素。结果表明:土壤养分的空间分布整体上符合正态分布(P<0.05),有效磷、速效钾和有机质的空间分布变异性较强,碱解氮和全氮的变异系数相对降低,并且随着土层深度的增加,土壤的养分含量呈现逐渐缩小趋势。土壤养分的各项指标能够较好地符合半方差函数模型,有机质和全氮具有较好的空间自相关性,碱解氮、速效钾和有效磷体现出中等自相关性,土壤养分整体分布格局的空间自相关性水平较强。土壤碱解氮含量等级为中等的比重最大,其面积占比为27.87%;有效磷、速效钾含量整体处于缺乏状态;而有机质含量在很丰富等级比重较大,且区域73.77%的土壤质地类型属于有机质丰富;全氮含量变化程度较低,并且大部分地区处于丰富的水平;区域土壤肥力的综合水平为IV。研究成果为区域土壤资源使用划分、修复重建以及可持续利用提供科学依据。

In order to reveal the spatial variations of soil nutrients and to guide the reasonable management of soil resources, the water-source forest in the mountainous areas and Beijing-Tianjin sandstorm source area in westem Beijing were taken as the study object, on the basis of field sampling and by using the method of combining geostatistics and GIS, the spatial distributions of soil available nitrogen, available phosphorus, available potassium, organic matter and total nitrogen were studied. Fuzzy pattern recognition theory was used to evaluate soil nutrient levels analyzed the influential factors of the spatial variation characteristics combined with the actual regional situation. The results showed that the spatial distribution of soil nutrients were in the normal distribution （P〈0.05）, the spatial variabilities of available phosphorus, available potassium and organic matter were stronger, the variation coefficients of available nitrogen and total nitrogen were lower, and soil nutrient gradually reduced with the increase of soil depth. The indexes of soil nutrients well fitted to the semivariogram model, organic matter and total nitrogen had good spatial autocorrelation, available nitrogen, available potassium and available phosphorus showed moderate autocorrelation, the spatial autocorrelation level of soil nutrient distribution pattern was strong. Available nitrogen was the highest in medium proportion, its area accounted for 27.87%, available potassium and available phosphorus were in lack states, but organic matter was very rich, and 73.77% of the soil texture types were rich in organic matter, total nitrogen was in abundance state with a low variation, the regional soil fertility was in comprehensive IV level. The research results can provide scientific basis for the reasonable division, rehabilitation and sustainable utilization of the regional soil resources.