EFFECTS OF ROOT GROWTH AND DECAY ON THE PERMEABILITY OF A SYNTHETIC SANDY LOAM

Abstract

The growth of corn roots through a column of synthetic sandy loam, initially devoid of organic matter, measurably compacted the soil between the root channels and greatly reduced the permeability of the column, under both sterile and non-sterile conditions. Typically, an 8% decrease in root-free pore space was accompanied by a 90% loss in permeability. Microscopic examination of sectioned columns showed that rotation and displacement of particles to positions of closer packing was most pronounced near the roots. A similar phenomenon has been postulated to account for observed decreases in infiltration rates on newly established perennial pastures.