An analysis of soil fractal dimension in a sloping hedgerow agroforestry system in the Three Gorges Reservoir Area, China

Abstract

Hedgerow intercropping provides an efficient method of controlling soil erosion and improving soil fertility on sloping agricultural land. Topsoil (0–20 cm soil layer) of 32 plots established in the Three Gorges Reservoir Area of the Yangtze River was sampled from the steep land between hedgerows (P1) and within hedgerows uphill (P2), under (P3) and downhill (P4) from the hedgerow were analyzed and the soil volumetric fractal dimension (DV) was calculated and the relationships between DV and soil physicochemical properties were tested. Results show that hedgerows effectively intercept clay particles in soil; the soil clay concentration within hedgerows was significantly higher (P < 0.05) than that of the soil between hedgerows at P1, respectively. The soil DV varied significantly among different positions in hedgerow systems, the DV of soil within hedgerows at P2, P3 and P4 were significantly higher (P < 0.05) than that of the soil between hedgerows at P1. DV was correlated positively and very significantly (P < 0.01) with the soil clay concentration (R 2 = 0.93) and silt content (R 2 = 0.74), and the DV was significantly (P < 0.01) and negatively correlated with soil sand content (R 2 = 0.78). The DV was significantly correlated with various soil physical properties and concentrations of soil nutrients. Therefore, the DV can be considered as a potential and accurate evaluating indicator for soil quality and nutrient conservation as they relate to the hedgerow intercropping on steep land.