Controls of Land Uses on Soil Retention Curve with Fractal Dimension: theory and Modeling

Use the soil water retention curve model to simulate the soil water retention curve in 3 different forestlands soil in Simian Mountains, and then the fractal dimensions of the curves of soil water retention were calculated with the corresponding experimental data. By analyzing the relationship between fractal dimension and the soil texture we found that the fractal dimensions of the curves of soil water retention and soil particle sizes increase gradually with the increase of clay content or decrease of sand content. Moreover, the fractal dimensions of the curves of soil water retention are slightly different from that of particle size distribution, and there is a positive correlation between their fractal dimensions. The curves of soil water retention are predicted with the fractal model, and results showed that the simulated values of soil water retention curves are similar to the observed values in both coniferous mixed forest and tillage. Both of their correlation coefficient were larger than 0.9. This reveals that the curves of soil water retention can be predicted with the fractal model in both coniferous mixed forest and tillage in the experimental area, which shows great guiding significance.