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.