差异演化算法在土壤分形维数估计中的应用

Applying Differential Evolution Algorithm to Optimize The Soil Fractal Dimension

根据UNSODA数据库的土壤颗粒大小分布和水分特征曲线资料,运用差异演化算法和分形模型,计算土壤的体积分形维数,并对分形维数与土壤体积含水量、进气压力及土壤质地等相关属性的关系进行统计分析。结果表明:分形维数反映了土壤中黏粒、粉粒和砂粒的含量变化,可以作为评价土壤质地差异的一个指标;分形维数随土壤黏粒比例的增大而增大,随砂粒比例的增大而减小;没有考虑土壤残余含水量的Brooks-Corey模型更适合运用差异演化算法来优化土壤分形维数;相比其它的拟合方法,用差异演化算法估算的分形维数具有更高的精度。

According to data of soil particle size distribution and water retention curve in the UNSODA database, differential evolution algorithm and soil fractal models were used to calculate the volume fractal dimension and statistically analyze the relationship among fractal dimension, soil volumetric water content, air-entry suction, soil texture, etc. The results showed that the fractal dimension reflect the content change of clay, silt and sand in soil, and it could be used as an indicator of soil texture. Soil fractal dimension increased with clay content in soil, and decreased with sand content. Brooks-Corey model without soil residual water content was more suitable for applying differential evolution algorithm to estimate soil fractal dimension. Compared with other optimization methods, differential evolution algorithm had higher precision in estimating the fractal dimension.