四面山两种土地利用方式下的优先流特征

发布时间：2018-03-23 04:16

本文选题：土地利用方式　切入点：染色示踪　出处：《北京林业大学》2015年硕士论文　论文类型：学位论文

【摘要】：水分和溶质等通过优先路径向下快速运移,不仅加大了水资源的消耗,还能造成地下水资源的污染,保护水资源、控制面源污染成为一项急需解决的问题。目前对不同土地利用方式下的优先流运动形态和规律研究较少,本文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 CS 4、Image pro Plus 6.0等软件进行图像处理,通过对土壤孔隙数量、优先流染色面积、染色路径数量、染色路径宽度等特征参数的计算,及对其类型的划分,来分析两种土地利用方式下的优先流特征。研究结果表明：(1)0.8-1.7mm的大孔隙是草地优先流形成的主要通道,而0.3～1.2 mm的大孔隙是农地优先流形成的主要通道。(2)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,但任意土壤深度处,草地的各个剖面染色面积波动变异程度均比农地的波动变异程度大,且草地各个剖面表现出明显的异质性,农地各个剖面却分布较均匀,很少出现较大反弹,说明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0.9以上,农地的相关系数则只有0.84,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。(3)草地土壤优先流发生发展不稳定,呈现“高相互作用大孔隙流—混合作用大孔隙流—高相互作用大孔隙流”和“非匀质指流—混合作用大孔隙流—高相互作用大孔隙流”为主的两种交替发生的模式,且不同剖面间优先流发生深度和部位均不同,土壤优先流发生类型变异度较高。农地样地优先流发生类型表现出较小的差异性,主要以“非匀质指流—混合作用大孔隙流—高相互作用大孔隙流”为主,土壤中优先流类型没有呈现交替出现的现象,说明农地土壤优先流发生发展较草地的稳定,优先流发生类型变异度较低。
[Abstract]:The rapid movement of water and solutes through priority paths not only increases the consumption of water resources, but also pollutes groundwater resources and protects water resources. Control of non-point source pollution has become an urgent problem. At present, there are few studies on the patterns and laws of preferential flow movement under different land use patterns. In this paper, the farmland and grassland of Simian Mountain in Chongqing are taken as the research objects. The occurrence area of preferential flow was observed by staining tracer method. The image was processed by Photoshop CS4 Image pro Plus 6.0. The characteristic parameters such as soil pore quantity, dyeing area of preferential flow, number of dyeing path and width of dyeing path were calculated. The characteristics of preferential flow under two land use patterns were analyzed. The results showed that the macropores of 0.8-1.7 mm in the proportion of 0.8-1.7 mm were the main channels for the formation of preferential flow in grassland. The macroporous area of 0.3mm. is the main channel for the formation of preferential flow of farmland. The grassland is more prone to the occurrence of preferential flow, the preferential flow is more active, the development degree of priority path is higher, but the soil depth is arbitrary. The variation degree of each section of grassland was higher than that of farmland, and there was obvious heterogeneity in each section of grassland, but the distribution of each section of farmland was even, and there was little rebound. The results showed that the stability of preferential flow was lower than that of farmland, and the root biomass of grassland was positively correlated with the dyeing area and the number of dyeing paths, and the correlation coefficient was more than 0.9. The correlation coefficient of farmland is only 0.84, which indicates that the occurrence and development of preferential flow of grassland is greatly affected by plant root system, and the farmland is affected by the joint action of tillage measures and plant roots. 3) the occurrence and development of preferential flow of grassland soil is unstable. There are two alternately occurring modes of "high interaction macropore flow-mixing macroporous flow-high interaction macroporous flow" and "non-homogeneous finger flow-mixing macroporous flow-high interaction macroporous flow". The occurrence depth and location of preferential flow were different among different sections, and the variation of the occurrence type of preferential flow in soil was higher, and the occurrence type of preferential flow in farmland showed little difference. The main phenomenon is "non-homogeneous finger-mixed macroporous flow-high interaction macroporous flow", and the preferential flow type in soil does not appear alternately, which indicates that the occurrence and development of preferential flow in farmland is more stable than that in grassland. The variance of priority flow occurrence type is low.
【学位授予单位】：北京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152.7

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