森林土壤大孔隙特征及其生态水文学意义

由于研究方法和目的的不同，土壤大孔隙的标准并不统一，一般认为土壤大孔隙的孔径在0．03～3mm；〉3mm的孔隙相对于土壤结构而言非常巨大，水流在这些孔隙中的运动完全不同于土壤中的运动方式，因此一般土壤大孔隙研究中不包含这种成因的巨大孔隙。对于森林土壤而言，动物活动和根系作用是大孔隙形成的主要原因。研究土壤大孔隙经常采用的方法有染色法、CT扫描技术和入渗方法；由于土壤大孔隙的高度不规则性，常采用分形理论研究大孔隙的特征。水分在大孔隙中的快速运动是大孔隙流的主要特征，因此模拟大孔隙流时经常采用可将土壤分为快速运动区域和运动较慢区域两个部分的两区模型。壤中流是森林涵养水源和调节径流的主要方式，土壤大孔隙对壤中流的产生具有重要的影响。研究森林土壤大孔隙，可深化森林涵养水源机理的认识，不仅在理论上可加深理解森林调节水文的过程；在实践上用于预测土地利用变化对水资源和水环境的影响，为退耕还林、天然林保护工程的植被恢复重建提供理论与决策依据。

The Macroporosity Properties of Forest Soil and Its Eco-hydrological Significance

The maeropore is a common phenomena to forest soil with notable influence to water transport in soil. The standard of macropore size has not been unified due to the differences among the research methodology and purposes. The macropore aperture was usually considered as 0.03- 3 mm. The pore of aperture larger than 3ram, which was very massive comparison with soil pore structure, was not concluded in soil macropre because of water transport form in these pores being different from normal soils. The activities of animals and function of roots were main causes of macropore formation for forest soil. The methodologies of macropore research had dye tracer, CT scanning and infiltration, and the fractal theory was also used to researched macropore characters. The most characteristic of macropore was water movement rapidly, So the two-region model was used widely, which the soil pores were divided into two parts, one part water moved rapidly and the other part water moved very slowly. The surface flow was principle formation for forestry adjusting runoff and conserving water, and the soil macropre significantly affected the surface flow formed. The study about forest soil macropore could further understand the mechanism of forest conserving water and the procem of forest adjusting runoff.