湖南烟区土壤pH分布特点及其与土壤养分的关系

pH distribution and relationship to soil nutrient in Hunan tobacco lands

测试分析了湖南烟区1089个土壤样本的pH，并分析了其与土壤养分的关系。结果表明：湖南烟区土壤pH总体适宜，平均为6．52，变异系数为16．81％；pH处于最适宜烤烟生长的5．5～6．5间的土壤样本占总样本数的26．91％；pH处于适宜烤烟生长的5．0～7．0间的土壤样本占52．71％。湖南不同烟区土壤pH大小表现为：湘南〉湘北〉湘西〉湘东；烟区不同土壤类型pH大小表现为：鸭屎泥〉黄壤土〉青泥田〉黄灰土〉黄泥田〉红黄泥。土壤pH与土壤有机质、全氮、速效磷、速效钾、有效锌、有效铁、水溶性氯、交换性钙和交换性镁的相关性均达1％极显著水平。土壤pH分组后，土壤养分含量在组间存在极显著差异。湖南烟区pH在5．5～6．5间的土壤的有机质、全氮、速效磷、有效锌和水溶性氯含量能够满足优质烤烟生长需求，有效锰、有效铁、交换性钙和交换性镁含量能满足烤烟的正常生长需求，有效钾和有效铜含量偏低，但尚未引起烤烟的缺素症状。

pH distribution in Hunan tobacco lands was analyzed from 1 089 soil samples and its relationship to soil fertility studied. The results indicate that soil pH in the tobacco lands is generally suitable for tobacco cultivation, with a spatial mean of 6.52 and variation coefficient of 16.81%. About 26.91% of the soil samples has pH between 5.5～6.5, most suitable for high quality tobacco cultivation. And 52.71% of the soil samples has pH of 5.0～7.0, also good for the growth of high quality tobacco. The soil pH for different parts of Hunan tobacco lands is in the following order： South Hunan 〉 North Hunan 〉 West Hunan 〉 East Hu- nan. The soil pH for different soil types is in the following order too ： duck-feces mud 〉 yellow soil 〉 blue mud field 〉 yellow ash soil 〉 yellow mud field 〉 red yellow mud. The correlation between soil pH and soil nutrient content, including organic matter, total N, available P, available K, available Zn, available Fe, water soluble Cl, exchangeable Ca and exchangeable Mg is all significant at 0.01 confidence level. Significant differences at 0.01 confidence level among different pH groups exist for the soil nutrients. Organic matter, total N, available P, available Zn and water-soluble Cl content of soils with pH 5.5 - 6.5 meet high quality tobacco production requirement. Soil available Mn, available Fe, exchangeable Ca and exchangeable Mg all meet the requirement of good tobacco growth. Finally, the content of available K and Cu is relatively low, however, no nutrient deficiency symptom is observed.