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以陕西省周至县北部农耕区为研究对象,选取有机质、碱解氮、速效钾和有效磷4个养分指标,利用主成分分析确定指标权重,将改进TOPSIS技术运用到土壤养分综合评价中,通过计算样点值与最优值、最劣值的距离,以评价对象与最优值的相对接近程度作为评价养分高低的依据,对土壤养分综合指数(Bi)进行COK插值,并绘制土壤养分等级分布图。综合评价结果表明:研究区Bi范围为0.109~0.603,平均值0.285,标准差0.083,变异系数29.12%,属中等变异程度;养分空间分布格局:除南部的马召镇和楼观镇部分区域的养分等级高,由西北角的青花乡、哑柏镇和东部的九峰乡、尚村镇向中部降低的趋势;从高到低的养分等级面积比例为3.47:16.11:29.61:33.12:17.68。研究区土壤养分等级总体偏低,且主要分布在中部地区,与实际情况相吻合,为农耕区土壤肥力改善提供科学依据。该方法相对准确的对土壤养分给予评价,为土壤养分评价提供一条新思路。
Taking the farming areas in the northern part of Zhouzhi County in Shaanxi Province as the research object, the four nutrient indices of organic matter, available nitrogen, available potassium and available phosphorus were selected. The principal component analysis was used to determine the index weights. The improved TOPSIS technique was applied to the comprehensive evaluation of soil nutrients. Calculate the distance between the sample value and the optimal value and the worst value, and use the relative closeness between the evaluation object and the optimal value as the basis for evaluating the nutrient level, perform COK interpolation on the soil nutrient comprehensive index (Bi), and draw the soil nutrient grade Distribution. The results of comprehensive evaluation showed that the Bi range of the study area was 0.109-0.603, with an average of 0.285, a standard deviation of 0.083 and a coefficient of variation of 29.12%, which belonged to a medium degree of variation. Spatial distribution pattern of nutrients: In addition to the areas of Mazhao and Louguan High nutrient levels, from the northwest corner of the Blue Flower Township, Mubai town and the eastern Jiufeng Township, Shangcun town to the central lower trend; from high to low nutrient grade area ratio of 3.47: 16.11: 29.61: 33.12: 17.68. The soil nutrient level in the study area is generally low and mainly distributed in the central region, which is consistent with the actual situation and provides a scientific basis for improving the soil fertility in the farming area. This method gives a relatively accurate evaluation of soil nutrients and provides a new idea for soil nutrient evaluation.