Indicators of Soil Aeration Status

Abstract

Summary The aeration status of a soil can vary over a wide range of values with a continual change in the physical, chemical and biological properties. In a well-aerated soil, the O2 content is high with a large percentage of the soil pore spaces filled with air. However, when soil pore spaces are filled with water, anoxia exists. It is impossible because of limited techniques to measure the degree or extent of anoxia in a soil profile. Anoxia involves more than mere absence of O2 in the soil. Many other redox systems are involved in determining the biological and chemical activities of a soil, and these redox systems are usually not affected until O2 has been depleted. Also, difficulties arise from the fact that whereas physical methods can predict the degree of O2 supply, it requires biochemical assays to determine the degree of demand. However, by studying results of certain measuring techniques and considering responses and products of organisms and plants, one can make value judgements about the soil environment. Many different methods have been devised which when coupled by appropriate statistical analyses, can be used to evaluate either qualitatively or quantitatively the aeration status of a soil. A review of these methods is presented in this report.