Spatial heterogeneity of soil properties and its relationships with terrain factors in broadleaved forest in Tiantong of Zhejiang Province, East China

By using geostatistical methods, this paper studied the spatial heterogeneity and distribution patterns of soil pH, total carbon, total nitrogen, and total phosphorus in an evergreen broadleaved forest in Tiantong of Zhejiang Province, and the effects of terrain factors (elevation, convexity, and slope) on the soil properties were quantified based on RDA ordination and partial regression analysis. The coefficient of variation for the soil pH, total carbon, total nitrogen, and total phosphorus was 5.18%, 42.98%, 36.55%, and 46.27%, respectively, and the spatial dependence of the soil properties was at a scale of 81.6-54.5 m. The soil pH, total carbon, and total nitrogen had moderate spatial autocorrelation, while the soil total phosphorus had a strong spatial autocorrelation. The soil pH, total carbon, and total nitrogen showed scattered spatial distribution, while the soil total phosphorus presented banded type. Among the terrain factors, convexity had the strongest effects on the soil pH and total phosphorus, both of which had negative correlation with convexity, and the convexity could explain 21.24% and 14.62% of the spatial variability of soil pH and total phosphorus, respectively. Elevation had the most powerful effects on the soil total carbon and total nitrogen, both of which had positive correlation with elevation, and the elevation could explain 10.54% and 10.60% of the spatial variability of soil total carbon and total nitrogen, respectively. There existed differences in the effects of different terrain factors on the spatial variability of the soil properties, which was related to the effects of terrain factors on the distribution of acidic rainfall in the region and on the local soil moisture content and air temperature.