【摘要】 以广西桂北岩溶区的3种典型农地为研究对象,通过野外染色示踪试验,结合形态学、数理统计以及分形理论等方法,对岩溶区玉米地、花生地和水稻田的土壤优先流特征进行了研究。结果表明:在相同供水条件下,玉米地土壤水流运动形成的染色形态由大面积的块状变为树枝状,土壤在20—40 cm深度范围内存在较多侧向孔隙通道,染色形态表现为由树枝状又变为较小的团块状,而花生地和水稻田的土壤水流运动形成的染色形态均由大面积的块状变为指状,但花生地水分以优先流形式入渗时还伴有一定程度的侧向运移,呈现指状染色形态中夹有较小的团块状染色形态,水稻田指状染色形态中无明显团块;玉米地的平均基质流深度达5.55 cm,是花生地的1.18倍,优先流发生时间相对花生地滞后,水稻田的平均基质流深度仅为2.36 cm,其最先发生优先流现象;玉米地的平均总染色面积比、优先流比和湿润锋迹线的分形维数(32.09%,71.59%和1.34)是花生地的1.40,1.04,1.05倍,水稻田的平均总染色面积比、优先流比和湿润锋迹线的分形维数分别为12.55%,62.03%和1.26,均小于玉米地和花生地,表现为玉米地优先流发育程度最大,其次为花生地,水稻田优先流发育程度最小。更多还原

【Abstract】 This paper concentrates on three types of typical farmland in the karst area of north Guangxi. Through field dyeing tracer test, the characteristics of soil preferential flow in corn field, peanut fields and paddy field in karst area were studied by combining with morphological, mathematical statistics and fractal theory. The results show that under the same condition of water supply, the dyeing form of soil water flow in corn field change from massive block to branch shape; the soil has more lateral pore channels in the depth range of 20—40 cm, which shows that the dyeing changes from dendrites to smaller clumps; however, the soil water movement of peanut fields and paddy fields change from massive block to finger-like; when the water infiltrates into peanut fields soil in the form of preferential flow, it is accompanied by a certain degree of lateral migration, that is, there are small clumps in finger-like dyeing form, there were no obvious clumps in finger-like dyeing patterns of rice fields. The average depth of matrix flow is 5.55 cm in the corn field, which is 1.18 times higher than that of peanut fields. And the occurrence time of preferential flow falls behind that of peanut fields. However, the average depth of matrix flow fields is only 2.36 cm in paddy, and preferential flow is the fastest. The results show that the average total dyeing area ratio, preferential flow ratio and fractal dimension of wet front trace(32.09%, 71.59% and 1.34) of corn field are 1.40, 1.04 and 1.05 times higher than those of peanut fields, and the average total dyeing area ratio, preferential flow ratio and the fractal dimension of wetting front trace in the paddy field are 12.55%, 62.03% and 1.26, respectively. All of them are smaller than corn field and peanut fields. The results showed that the development degree of priority flow is the highest in corn field, followed by peanut fields, and the lowest in paddy field.更多还原