Characteristics Of Preferential Flow Under Two Kinds Of Land Use Patterns In Simian Mountain

Water and solute transported quickly through the preferential flow paths, it increased not only the water consumption, but also the groundwater pollution. It had become an urgent problem to protect the water resource. There were few studies on the preferential flow movement patterns, so there was a great need to fully understand preferential flow. Dye tracing method was used to observe the occurrence of preferential flow region in the Simian Mountain’s grass land and agricultural land. Characters of preferential flow under thus two land use was obtained by figuring out the feature parameters of preferential flow. The results showed:(1)The macropore diameter in the range between 0.8-1.7 mm was the main channel of preferential flow in the grassland, while 0.3-1.2 mm was the main channel of preferential flow in the agriculture land.(2) The preferential flow of grass land was more active and mature, but the stability was lower than agricultural land. The root biomass of grass land was a positive correlation with both stained area and preferential flow paths. The correlation coefficient of grass land was more than 0.9 while the agricultural land was only 0.84, which demonstrated the preferential flow of grass land was greatly influenced by plant roots while agricultural land preferential flow was affected by the interaction of tillage and plant roots.(3)The preferential flow of grassland occurred unstably, which presented a pattern of "high interaction-mixed interaction- high interaction" and the other pattern of "heterogeneous-mixed interaction-high interaction". The preferential flow occurred with high variability. While the preferential flow occurred with minor difference on the agricultural land, which presented a pattern of "heterogeneous-mixed interaction-high interaction". This phenomenon indicated that the preferential flow of agricultural land was more stable.