SOIL MORPHOLOGY AND SOIL PHYSICAL PROPERTIES. I. SOIL AERATION

Abstract

The relation between soil structure and soil aeration was investigated on undisturbed soil cores from soil horizons exhibiting six distinct kinds of soil structure (prismatic, columnar, blocky, granular, platy, massive) over a broad range of soil texture. Soil aeration was characterized at ⅓ atm suction by measurements of air porosity, relative diffusivity (D/Do) and the rate of oxygen diffusion to a platinum microelectrode (ODR). Aeration was adequate in most of the Chernozemic soil horizons studied; however, aeration in many of the Bnt horizons of the Solonetzic soils was inadequate. Air porosity and D/Do were highly correlated. The regression coefficient for D/Do vs. air porosity for blocky structures was significantly different from that found for the other five structural types. For granular structures a negative correlation was found for ODR vs. air porosity compared with a low positive correlation found for the other structure types.