西安市蔬菜种植区土壤属性的空间变异与肥力适宜性

Spatial Variation and Fertility Suitability of Vegetable Field in Xi'an City

[目的]对西安市蔬菜区土壤属性空间变异与肥力适宜性进行评价,为相关部门土壤培肥和蔬菜种植提供决策依据。[方法]选择与蔬菜生长密切相关的土壤pH值、电导率、有机质、碱解氮、有效磷、速效钾六个指标,利用半变异函数进行空间变异分析,应用模糊综合法计算土壤肥力适宜性指数(SFI),对SFI进行Kriging插值,采用等间距法划分等级,并对土壤肥力进行综合评价。[结果]半变异函数能较好的拟合蔬菜区土壤空间变异特征,人为施肥成为影响土壤电导率、碱解氮空间变异的主要因素,土壤pH值和其他养分则同时受到结构性因素和随机性因素的作用。[结论]西安市蔬菜区土壤肥力适宜性处于中等较好水平,限制蔬菜生长的主要因素是土壤有机质和碱解氮含量。临潼区东南部,鄠邑区、周至县北部地区以及长安区和鄠邑区北部交界处蔬菜区土壤肥力有待提高,菜农需要采取措施提高土壤有机质含量和补施氮肥。

[Objective] To evaluate the spatial variation and fertility suitability of vegetable field in Xi＇an City, Shaanxi Province, in order to provide a basis for making decision of soil cultivation and agricultural production in relevant departments.[Methods] Six indexes that are closely related to vegetable growth including soil pH value, electrical conductivity, organic matter, alkali-hydrolysable nitrogen, available phosphorus and available potassium, were measured. Their spatial variability was analyzed using semi-variation function. And the soil fertility suitability was determined using fuzzy mathematics method. The soil fertility suitability was graded by equal spacing method after Kriging interpolation was conducted, and finally it was evaluated comprehensively.[Results] The semi-variogram could fit the spatial variability of soil in the vegetable field. The spatial distributions of the conductivity and alkali-hydrolysable nitrogen were mainly affected by the fertilization, and the soil pH value and other nutrient were affected by both anthropogenic and natural factors.[Conclusion] The soil fertility suitability of vegetable field in Xi＇an City was at middle level, and the main limiting factors of vegetable growth were soil organic matter and alkali-hydrolysable nitrogen content. There are some areas where the soil fertility of vegetable field should be improved. These areas are the south-eastern of the Lintong District, the northern of the Huyi District and the Zhouzhi County, the northern part next to Chang＇an District and the Huyi District. To the vegetable farmer, measures that can improve the contents of soil organic matter and nitrogen should be taken.