黄淮平原地区典型县域耕地土壤肥力评价

Soil fertility evaluation of cultivated land in typical counties of Huanghuai Plain

土壤肥力是土壤基本性质及生产力的综合表现,在江苏省响水县研究区内进行土壤肥力评价有利于了解该县土壤肥力空间分布状况,对黄淮平原耕地资源的合理利用具有重要作用。本研究利用地统计分析法和主成分分析法筛选土壤肥力指标以构建肥力评价的最小数据集(MDS),同时运用加权求和法计算出土壤肥力指数(SFQI),建立反映响水县研究区土壤肥力的综合评价体系。结果表明,响水县研究区土壤有机质、全氮、有效铁、有效铜和有效钼含量丰富,均值整体处于一级水平;土壤有效磷含量较为缺乏,整体为四级水平。除pH以外,变异系数均大于10%,各指标块基比均在25%以上,空间自相关性较弱。研究区土壤肥力评价的MDS为pH、容重、全氮、速效钾、有效铜、有效钼,能够较好地反映全量数据集(TDS)对土壤肥力评价的信息。研究区整体土壤肥力处于三级地力水平,呈现西北高东南低的空间分布特征。速效钾和有效钼是研究区的主要限制因子,建议在施用氮、磷、钾肥时提高钾肥比重,增施微量元素肥料,以提高土壤肥力。本研究结果可为黄淮平原耕地土壤肥力评价和耕地土壤培肥提供参考。

Soil fertility is the comprehensive performance of soil basic properties and productivity.Soil fertility evaluation in the study area of Xiangshui County of Jiangsu province is beneficial to understanding the spatial distribution of soil fertility,and plays an important role in the rational utilization of cultivated land resources in Huanghuai Plain.In this study,statistical analysis and principal component analysis were used to screen soil fertility indicators to construct a minimum data set(MDS)for fertility evaluation.At the same time,weighted summation method was used to calculate soil fertility index(SFQI),and a comprehensive evaluation system reflecting soil fertility in the study area was established.The results showed that the contents of organic matter,total nitrogen,available molybdenum,available iron and available copper were abundant,and the average value was at the first level.The content of available phosphorus in soil was relatively lacking,and the overall level was the fourth level.Expect for pH,the coefficients of variation of other indicators were greater than 10%,and the ratio of nugget value to sill value of each index was above 25%,and the spatial autocorrelation was weak.MDS for soil fertility evaluation in the study area included pH,bulk density,total nitrogen,available potassium,available copper and available molybdenum,which could better reflect the information of soil fertility evaluation by total data set(TDS).The overall soil fertility in the study area was at the third level,showing the spatial distribution characteristics of high in northwest and low in southeast.Available potassium and available molybdenum were the main limiting factors in the study area.In order to improve soil fertility,it was suggested to increase the proportion of potassium fertilizer and increase the application of trace element fertilizer.The results of this study can provide a reference for soil fertility evaluation and soil fertilization in Huanghuai Plain.