| Preferential paths characteristics and its influence factors of formation in conifer-broadleaf forest land and Phyllostachys pubescens land in Simian mountains, Chongqing, was studied. Outdoor dyeing tracer method was used to explore water and solute transport. Soil profiles where there were preferential flow way occurred were photographed for further process and analysis. Collect soil sample and root in bright blue dyeing area and unstained area of soil profiles in the sample plots, and measure the physical properties of soil sample, root length and dry weight through indoor experiment, anaylsed the distribution characteristics of two kinds of forest priority and its influencing factors the results showed that.The results show patterns of water infiltration in these two kinds of forest soil were different. Width and amount of staining paths were heterogenous in different depths of a profile and different profiles at the same depth. The average dying path of conifer-broadleaf forest land looks like "Inverted ladder" while that of Phyllostachys pubescens land has a S-type. Staining path width and the number of staining path in these two forests reduced gradually with the increase of soil depths.Based on water breakthrough curve theory and combining with the Poiseulle equation and flow equation, the relationships between soil macropores and the preferential flow were quantitatively researched in mixed broadleaf-conifer forest and Phyllostachys pubescens forest, Zhang Jiashan forest district, Simian Mountains, Chongqing. It showed that the water steady effluent volume in 0 to 10 cm soil layer of the two kinds of woodlands was both more than 0.7 ml/s,and that in deeper layer was both declining gradually. Besides, effluent volume in dye-stained areas was 2.42-2.84 times higher than that in blank areas,while Phyllostachys pubescens forest’s reached 3.0-3.14 times.The radii of soil macropores ranged from 0.4 to 3.2mm.The path of preferential flows were mainly found in the macropores with radii larger than 1.5mm.Through the analysis of the soil density, soil texture, organic matter and root system,it was found that the soil density in the dyeing area is lower than the unstained area and it increased gradually with the increase of soil depth in both of the forests. T test showed that there was no significant relationships between the dyeing area and the unstained area in two forest lands which indicated that two forest soils were at fairly overall development levels. Besides, according to the results of the determination of organic matter, higher organic matter content exists in dyeing area rather than unstained area, root length and root weight density showed the root system of the plants play an important role in promoting the formation of the preferential flow in the soils. |
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