It is essential to understand spital variability of soil properties in tobacco planting regions, for the right decision can be made as to how many fertilizer rates are likely to be appropriate for the high quality tobacco production. In this paper, a total of 159 soil samples were taken from surface soil(0 ~20) of Xiangcheng tobacco planting fields, Henan province in April 2007 for examing the concentration of soil organic matter, pH, available N, available P and available K . Spatial variability of above mentioned was evaluated using geostatistics and geographic information system( GIS) analyses. The objective of this study was to provide a scientific basis for field management targeting at improving soil quality in this tobacco planting region. The results showed that among those five soil fertility factors, the variation coefficient of soil pH is the smallest, while that of available P is the greatest which demands more samples under the same precisions, which are resulted from different cultivation methods and uneven fertilization. Analysis of the isotropic variogram indicated that the soil pH, organic matter and available P semivariogram were well described with spherical models,with the distance of spatial dependence being 21 020,19 150 and 8 460 m respectively,while the available N and available K semivariogram were well described with exponential model, with the distance of spatial dependence being ranged from 7 484 to 25 320 m. Soil pH value was strongly spatiallydependence with CO/sill being 0. 193 5 , while other four soil fertility factors were moderately spatial dependent with CO/sill being range from 0. 352 8 to 0. 526 0. With the kriging analysids, the spatial distribution maps of soil properties in Xiangcheng tobacco planting regions was drawn. In the paper, the index system of soil fertility suitability of tobacco was established. S-or parabola-type dependence functions were developed according to their effect on tobacco crop and the function value was also calculated. AHP was applied to judge the weight of each evaluation factor, then the integrated index val ues for every evaluation unit were obtained. And the fertility map of Xiangcheng tobacco planting regions was drawn with GIS software mapGIS. The results indicated that the optimum fields for Flue-tobacco crops growth were found in the east-southern part of the investigated regions, accounting for 5. 02% of the whole area, while the soil with suitability fields were mainly distributed in the northern and middle-southern part of the investigated regions, occupying 80. 15% of the whole area. And the fields with less suitability existed in the middle of this given regions, accounting for 14. 28% of the whole area.%采用统计学与地统计学相结合的方法,结合GIS技术,对河南省襄城县植烟田耕层(0～20 cm) 159个土壤样本进行了数据处理,分析了土壤有机质、pH、速效氮、有效磷和速效钾含量的空间分布特征,结果表明:土壤pH的变异系数最小,而有效磷由于不同的耕作措施和不均衡施肥,其变异系数最大.半方差分析表明,土壤有机质、pH和有效磷符合球状模型,最大相关间距分别为21 020、19 150和8460 m,而有效氮和速效钾符合指数模型.最大相关间距分别为7 484和25 320 m,土壤pH的C0/sill为0.193 5,具有强烈的空间自相关性,而其他四种土壤肥力因子的C0/sill为0.352 8 ～0.526 0,为中等强度的空间自相关性.并采用Kriging方法进行最优内插,绘制了襄城植烟田各土壤肥力因子含量的空间分布图.建立了烤烟土壤肥力适宜性评价指标体系,运用模糊数学和层次分析法对土壤肥力水平进行了综合评价、分级.采用地理信息系统软件mapGIS绘制襄城县烤烟种植区土壤肥力状况图.结果表明,烟草种植区土壤肥力适宜性水平存在着相当程度的差异,表现出明显的空间异质性.土壤肥力适宜性最高的地区位于研究区的东南部,占研究区总面积5.02％;适宜性为适宜的位于研究区的北部和中南部,占研究区总面积的80.15％;而次适宜的植烟田横穿于研究区的中部,占研究区总面积的14.28％.
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