Discussion of “pedological relations of infiltration phenomena”

Abstract

Smith provides an illuminating consideration of infiltration through soil in relation to the structure and texture of the soil its moisture content, and the variation of infiltration for A, B, and C soil zones. The organic nature of soil might also be stressed. Rotting rootlets provide passageways for water in addition to physical structure and texture. The impression is gained that mechanical treatment, such as plowing and harrowing, general decreases the infiltration capacity of soil, through destruction of surface structure, and fragmentation. This appears true of the soil in the physical sense. Equally true, in a plowed soil, may be the formation of puddling colloids after a rain, through the breaking of natural granules into fragments. However, the surface infiltration is increased by plowing and harrowing through the turnover of the sod layer composed of grasses and weeds. Smith does not consider the sod layer as a soil zone, yet it is the first barrier that precipitation must pass before it enters the structural crevices and textural pores of the soil. Although a dense sod layer usually does not increase runoff because of its retentive nature, it increases interception, and hence evaporation, so unless the sod is economic, the water is lost anyway.