云南元谋冬早蔬菜主产地土壤肥力的空间变异特征与评价

Spatial Variability Characteristics and Evaluation of Soil Fertility in the Main Winter-early Vegetable Production Areas of Yuanmou,Yunnan

【目的】明确云南元谋露天冬早蔬菜主产地的土壤肥力空间变异特征,为该区域的土壤培肥管理提供科学依据。【方法】在元谋县蔬菜主产区的露天菜地区域选择28个样点,采集土壤样品,测定其pH、电导率、含水率、容重以及有机质、全盐、有效磷、速效钾、硝态氮、交换态钙和交换态镁的含量共11项土壤肥力指标,并采用ArcGIS分析其空间变异特征。选择隶属度函数曲线并确定隶属度函数,根据各项土壤肥力指标的权重值和隶属度值计算土壤肥力指标的综合得分;再采用主成分分析和聚类分析分别对菜地土壤肥力进行综合评价。【结果】元谋县典型露天菜地土壤的平均pH值为7.54,属于弱碱性土壤,有机质和速效钾含量较高,有效磷含量处于中等偏上水平。土壤有机质与交换态镁含量的空间分布特征非常相似,土壤电导率、全盐量和有效磷含量的空间分布较为一致。土壤肥力单项指标分析显示:元谋老城乡和黄瓜园镇的隶属度值雷达图面积较大,4个乡镇的pH值、速效钾、电导率、全盐量等指标变异较小,而有机质、交换态镁、有效磷等指标变异较大。主成分分析显示:前3个主成分贡献了原始数据信息总量的70.670%,其中有机质的权重系数最大(0.1128),其次为交换态镁(0.1125)和有效磷(0.1123)。元谋菜地土壤肥力的综合得分为0.247~0.903,其中60.7%的样点低于平均值,主要集中在物茂乡和元马镇。聚类分析显示:全县菜地样点可划分为肥力良好型(39.29%)和肥力中等型(60.71%)。【结论】元谋县大部分区域的露天菜地土壤肥力水平良好,其中,有机质、交换态镁和有效磷对土壤肥力的贡献率较大,在该县菜地土壤肥力中起重要作用,但局部区域的土壤肥力亟待改良。

[Purpose]To identify the spatial variability characteristics of soil fertility in the main production areas of winter-early vegetables in Yuanmou County,Yunnan Province,providing a scientific basis for soil fertility management in the area.[Methods]A total of 28 sampling points in the main open-field vegetable production areas of Yuanmou County were selected.Soil samples were collected and analyzed for 11 soil fertility indexes,including pH,electrical conductivity,moisture content,bulk density,and the content of organic matter,total salt content,available phosphorus,available potassium,nitrate nitrogen,exchangeable calcium,and exchangeable magnesium.Spatial variability characteristics analysis was conducted by ArcGIS.Additionally,membership function curves were selected and determined,comprehensive scores of soil fertility were calculated based on the weight values and membership values of each soil fertility index.Principal component analysis and cluster analysis were conducted to comprehensively evaluate the soil fertility of the vegetable fields.[Results]The average pH value of the typical open-field vegetable soils in Yuanmou County was 7.54,indicating weakly alkaline soils.The organic matter and available potassium contents were high,while the available phosphorus content was at an upper-moderate level.The spatial distribution characteristics of soil organic matter and exchangeable magnesium were very similar,and the spatial distribution of soil electrical conductivity,total salt content,and available phosphorus were consistent.Single soil fertility index analysis indicated that the radar chart areas of the membership values for Laocheng Town and Huangguayuan Town were larger,and the variability of pH,available potassium,electrical conductivity,and total salt content among the four townships were smaller,but the variability of organic matter,exchangeable magnesium,and available phosphorus were larger.Principal component analysis revealed that the first three principal components accounted for 70.670%of the total information.Organic matter had the highest weight coefficient(0.1128),followed by exchangeable magnesium(0.1125)and available phosphorus(0.1123).The comprehensive soil fertility scores of Yuanmou’s vegetable fields ranged from 0.247 to 0.903,with 60.7%of the sampling points below the average score,mainly concentrated in Wumao Town and Yuanma Town.Cluster analysis showed that the sampling points in the county could be divided into two categories:good fertility type(39.29%)and moderate fertility type(60.71%).[Conclusion]The open-field vegetable soils in most areas of Yuanmou County have good fertility levels.Organic matter,exchangeable magnesium,and available phosphorus contribute significantly to soil fertility and play important roles in the fertility of the vegetable fields in the county.However,the soil fertility in some areas needs urgent improvement.