Visual soil quality assessment: A review

Abstract

Many physical, biological, and, to a lesser degree, chemical soil properties show up as visual characteristics; altered markedly by changes in land use and management. Many visual indicators like colour, structure, aggregation, texture, porosity, moisture conditions, earthworm casts are closely related to key quantitative indicators of soil quality. As indigenous people have done before, soil science and soil advisory services utilize the same common field diagnostic criteria within defined frameworks and check their validity over larger scales. Conventional methods for assessing soil quality under different management practices require considerable time and knowledge. Visual techniques of soil examination and evaluation are of immense value for soil management, particularly methods associated with the rapid assessment of soil. They complement newly developed techniques for soil assessment such as remote sensing and soil-landscape modeling, and well established procedures such as laboratory analysis of soil samples.