基于GIS的农田土壤肥力评价及其与土体构型的关系

以河南省延津县中低产田为例，选取土壤有机质、全氮、全磷、全钾、速效氮、速效磷、速效钾、pH和阳离子交换量（CEC）等指标作为评价因子，利用ArcGIS 9.2软件和模糊数学方法对土壤肥力进行了综合评价，根据评价结果，分析不同土体构型土壤肥力状况差异.结果表明：该区土壤呈偏碱性状态，全氮、全磷、速效氮、CEC、有机质、速效钾含量偏低，速效磷、全钾含量中等，土壤肥力综合指数为0.14～0.63，整体水平偏低.除速效磷和全钾外，其他土壤肥力指标在不同土体构型间均表现出显著差异，土壤肥力与土体构型关系密切，上壤下粘型土壤的肥力等级相对较高，上壤下砂型次之，通体砂型最低.根据各指标在剖面上的分布状况判断，该区土体结构不良，保水保肥能力差，可针对此特征进行土壤改良.

GIS-based evaluation of farmland soil fertility and its relationships with soil profile configuration pattern

Taking the mid and low yielding fields in Yanjin County, Henan Province as a case, and selecting soil organic matter, total N, total P, total K, available N, available P, available K, pH value, and cation exchange capacity as indicators, a comprehensive evaluation on soil fertility was conducted by the method of fuzzy mathematics and using software ArcGIS 9.2. Based on this evaluation,the differences in the soil fertility level under different soil profile configuration pattern were analyzed. In the study region, soils were slightly alkaline,poorer in total N, total P, available N, cation exchange capacity, organic matter, and available K, and medium in available P and total K. The integrated fertility index was 0.14-0.63, indicating that the soil fertility in the region was on the whole at a lower level. There existed significant differences in all indicators except available P and total K under different soil profile  configuration patterns (P<0.05), suggesting the close relationship between soil fertility and soil profile  configuration. The soil profile loamy in surface soil and clayey in subsurface soil had a higher level of soil fertility, followed by that loamy in surface soil and sandy in subsurface soil, and sandy in both surface and surface soil. Overall, the soils in the region were bad in profile  configuration, poor in water and nutrient conservation, and needed to be ameliorated aiming at these features.