دانلود مقاله ترجمه شده توزیع تخلل و اندازه خلل و فرج

A soil’s porosity and pore size distribution characterize its pore space, that portion of the soil’s volume that is not occupied by or isolated by solid material. The basic character of the pore space affects and is affected by critical aspects of almost everything that occurs in the soil: the movement of water, air, and other fluids; the transport and the reaction of chemicals; and the residence of roots and other biota. By convention the definition of pore space excludes fluid pockets that are totally enclosed within solid material—vesicles or vugs, for example, that have no exchange with the pore space that has continuity to the boundaries of the medium. Thus we consider a single, contiguous pore space within the body of soil. In general, the pore space has fluid pathways that are tortuous, variably constricted, and usually highly connected. Figure 1 is an example of a two-dimensional cross section of soil pore space. The pore space is often considered in terms of individual pores--an artificial concept that enables quantifications of its essential character. Though many alternatives could serve as a basis for the definition of pores and their sizes, in soil science and hydrology these are best conceptualized, measured, and applied with respect to the fluids that occupy and move within the pore space