Variability of soil moisture and its relationship with environmental factors on Karst hillslope

The aim of the experiment is exploring the influence of environmental factors, such as different land uses, topography and microgeomorphology, on the variability of soil moisture on Karst hillslope. The method of detrended canonical correspondence analysis (DCCA) was used to analyze surface soil moisture (0–15 cm) variability and its relationship with environmental factors on a typical hillslope in Karst region. The results showed that surface soil moisture ranged from 21.36% to 32.58% during the whole sampling periods, and had seasonal changes with middle variability. Soil moisture in different land uses had similar changes with time accompanied with four peak types. Soil moisture was the highest in natural vegetation field, followed in abandoned field and sloping field, and the lowest was in artificial forest. The DCCA ordination analysis indicated that soil depth, soil organic carbon, land use and bare rock ratio had the biggest effects on soil moisture variability and seasonal pattern on the hillslope. Soil density and slope had the less effects, and vertical position and height had the least effects. The sampling spacing and density of soil moisture should be increased, and aspect, curvature, upslope contributing area should also be considered in further studies according to the special physiognomy of Karst hillslope. Furthermore, these results suggested that combined with the soil nutrient characteristics of different land use on the hillslope, some feasible agricultural engineering measures and vegetation restoration modes should be developed on the degraded ecosystems on Karst hillslope in the future.