The pH Distribution and Its Relationship with Soil Nutrient at Different Altitudes——A Case study of Tobacco Fields in Qujing, Yunnan Province

The research analyzed the p H values and soil nutrient contents of 3690 soil samples, selected from the tobacco fields at different altitudes in Qujing, Yunnan Province. The results indicated that the p H value was about 6.3± 0.9 and its variation coefficient was 13.75% in tobacco field of Qujing. The range of p H suitable for tobacco growth is 5.0 ~ 7.0. This level p H accounted for 68.58% of soil samples, which located at altitude of 1322 ~ 2380 m. The soil p H declined with the increase of altitude. The correlations between soil p H and nutrients showed different changes at different levels of altitudes. Significant differences in soil nutrients were found between different levels of p H. At p H5.5 ~ 6.5, the contents of soil organic matter, total N, available P, available Ca, available Mg, available Cu, available Mn, available S were very abundant, and available N and available K moderate, and total P, total K, available B very low.