Spatial variability of soil nutrients in Juglans regia plantations in depressions between karst hills

To understand the spatial variability of soil nutrients in plantation forest in depressions between karst hills, we examined the characteristics and spatial variability of soil nutrients in Juglans regia plantation in Fengshan County, Southwest China. Most soil nutrients had moderate variability, and coefficients of variation for eight soil chemical characteristics differed according to stand age. All soil nutrient data were normally distributed and could be fitted to Gaussian, spherical, and exponential models, and nutrients showed strong spatial dependence and patterns that differed according to stand age. The distribution of soil nutrients was mainly affected by topography and habitat characteristics (elevation, slope, slope aspect, slope location, and bare rock cover). Our results suggest that stand age as a temporal factor and topography as a spatial factor contribute to patterns of soil nutrients in depressions between karst hills of Southwest China.