Spatial Variability and Suitability Evaluation of Acid and Secondary Elements in Tobacco Planted Soil from Slope Farmland

312 soil samples were collected from tobacco planted area in slope farmland in Wulong County of Chongqing city,and their pH and secondary element content were measured,and then the modified Nemero formula was adopted to evaluate quality of the soil samples.The results showed that the average value of soil pH,exchangeable Ca content,exchangeable Mg content and effective S content in tobacco soil in Wulong county was 5.82,2.50 g/kg,0.15 g/kg and 31.49 mg/kg,respectively.According to the nutrient classification standards of second national soil survey,the pH and the exchanging Mg content of the soil samples are in a middle level or slightly lower in general,the exchangeable Ca content and the effective S content are in a rich level in general;variance in soil pH is little,variance in effective S content is relatively larger,and variance in exchangeable Ca content and exchangeable Mg content are moderate.The quality index of tobacco soil is 1.81 through a comprehensive evaluation,which is basically suitable for tobacco planting.