Characteristics of Preferential Flow and Quantitative Evaluation of Dyeing Morphology in Different Forest Types on Simianshan Mountain in Chongqing

The Iodine−starch staining tracer test was used to quantitatively evaluate the characteristics of soil preferential flow and its staining morphology. With the help of image processing technologies and data processing methods such as Adobe Photoshop and IPWIN, broad-leaved forest, coniferous forest, shrub and grassland of Simianshan Mountain in Chongqing were used as research objects. The results showed that the soil preferential flow of broad-leaved forest land, coniferous forest land, shrub and grassland developed obviously in 5–25, 10–30, 10–25 cm and 5–20 cm, respectively. In general, the ratio of vertical slices of each forestland decreased with the increase of soil depth, the surface layer of broad-leaved forest and coniferous forest decreased rapidly from 0–10 cm; with the increase of soil depth, the shrub decreased first, then basically unchanged, and then decreased.The ratio of total dyeing area of broad-leaved forest and coniferous forest was higher than that of shrub forest and grassland, the preferential flow ratio and length index of broad-leaved forest soil were also higher than those of coniferous forest, shrub and grassland.