2种土地利用方式下的优先流特征

Characteristics of Preferential Flow Under Two Kinds of Land Use Patterns

以重庆四面山的农地和草地为研究对象,利用染色示踪法观察优先流的发生区域,采用Photoshop CS4、Image pro Plus 6.0等软件进行图像处理,通过对优先流形态特征参数的计算,分析2种土地利用方式下的优先流特征。研究结果表明:草地的优先流运动深度可达50cm,各剖面染色面积表现出明显的异质性,农地染色深度则集中于0-20cm土层,各剖面染色面积分布均匀,除7-8cm土层以外,其余各处草地染色路径数量均比农地的多,说明草地更易于优先流的发生,优先流较活跃,优先路径的发育程度较高,但优先流稳定性比农地低。草地的根系生物量与染色面积和染色路径数量呈正相关关系,相关系数达0.95以上,农地的相关系数则只有0.87,说明草地优先流的发生发展受植物根系的极大影响,农地则受耕作措施和植物根系的共同作用。

Dye tracing method was used to observe the occurrence of preferential flow region in the Simian Mountain＇s grass land and agricultural land. Characteristic of preferential flow under two land use patterns was obtained by figuring out the feature parameters of preferential flow. The results showed. The depth of grass land preferential flow could reach to 50 cm and the stained area of vertical profiles showed significant heterogeneity. However, the dye-stained scope concentrated in the 0--20 cm soil depth and various stained area of vertical profiles showed an uniform distribution on the agricultural land. The preferential flow paths of grass land were more than that of agricultural land except the soil depth of 7--8 cm. This phenomenon indicated that the preferential flow of grass land was more active and mature, but the stability was lower than that of agricultural land. The root biomass of grass land was a positive correlation with both stained area and preferential paths. The correlation coefficient of grass land was more than 0.95 while the agricultural land was only 0.87, 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.