喀斯特地区湘西州植烟土壤pH分布特征及其影响因素

为了解湘西州植烟土壤pH特征,于2015年采集湘西烟区1 242个土壤样本,采用传统统计学和地统计学方法分析了湘西州植烟土壤pH区域分布和空间分布特征及其影响因素。结果表明:(1)湘西烟区植烟土壤pH变幅为4.17~8.17,平均值为6.12,变异系数为18.30%;处于植烟土壤pH适宜范围内(pH为5.5~7.0)的样本占34.06%,pH小于5.0的植烟土壤样本为20.77%,pH大于7.5的植烟土壤样本为18.20%;(2)7个主产烟县植烟土壤pH平均值在5.44~6.84;不同县植烟土壤pH差异极显著;(3)植烟土壤pH有从西向东递减的分布趋势;(4)成土母岩、土壤类型、水土流失状况、灌溉能力、海拔高度、耕作层厚度、有机质含量、土壤颗粒组成显著影响植烟土壤pH;(5)水土流失严重、无灌溉能力和耕作层较浅的烟田、紫色砂页岩发育的土壤、红壤和红黄壤以及粘粒比例较大的土壤容易酸化;(6)土壤pH呈现出随海拔降低和有机质含量升高而升高的趋势。

Distribution Characteristics of Tobacco-growing Soil pH and Its Influencing Factors in Karst Region of Xiangxi

A total of 1 242 soil samples were collected from the main tobacco-growing areas in Xiangxi in 2015, and their soil pH were determined to study the areal distribution and spatial distribution of tobacco-growing soil pH and its influencing factors in order to understand the characteristics of tobacco-growing soil pH . The results were as follows:(1) pH of tobacco-growing soil in Xiangxi was generally suitable for tobacco cultivation with a mean of 6.12, amplitude of 4.17 to 8.17 and variation coefficient of 18.30%. About 34.06% of the soil samples had pH between 5.5 to 7.0, which was suitable for high quality tobacco cultivation. About 20.77% of the soil samples had pH less than 5.0, and 18.20% of the soil samples had pH greater than 7.5. (2) The means of tobacco-growing soil pH in 7 main tobacco-growing counties were between 5.44 to 6.84. There were extremely significant differences among different counties for the tobacco-growing soil pH. (3) IDW interpolation map indicated that the spatial distributions of tobacco-growing soil pH were reduced from the west to the east. (4) The tobacco-growing soil pH was affected significantly by soil forming rock, soil type, soil erosion condition, irrigation capacity, altitude, topsoil depth, organic matter content and soil mechanical composition. (5) The topsoil acidification was easy to occur in the tobacco-planting field of serious erosion, non-irrigation capacity and shallow topsoil, in the soil development by purple gritstone, in red soil and red-yellow soil, and in the soil of high clay particle content. (6) The tobacco-growing soil pH increased with the rise of soil organic matter content and the decrease of altitude.