Soil quality refers to the condition of
soil
Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...
based on its capacity to perform
ecosystem services
Ecosystem services are the various benefits that humans derive from Ecosystem, ecosystems. The interconnected Biotic_material, living and Abiotic, non-living components of the natural environment offer benefits such as pollination of crops, clean ...
that meet the needs of human and non-human life.
[Tóth, G., Stolbovoy, V. and Montanarella, 2007. ]
Soil Quality and Sustainability Evaluation - An integrated approach to support soil-related policies of the European Union
", EUR 22721 EN. 40 pp. Office for Official Publications of the European Communities, Luxembourg
Luxembourg, officially the Grand Duchy of Luxembourg, is a landlocked country in Western Europe. It is bordered by Belgium to the west and north, Germany to the east, and France on the south. Its capital and most populous city, Luxembour ...
. .
Soil quality reflects how well a soil performs the functions of maintaining
biodiversity
Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...
and productivity, partitioning water and solute flow, filtering and buffering,
nutrient cycling
A nutrient cycle (or ecological recycling) is the movement and exchange of inorganic and organic matter back into the production of matter. Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cyc ...
, and providing support for plants and other structures.
Soil management
Soil management is the application of operations, practices, and treatments to protect soil and enhance its performance (such as soil fertility or soil mechanics). It includes soil conservation, soil amendment, and optimal soil health. In agricult ...
has a major impact on soil quality.
Soil quality relates to
soil functions
Soil functions are general capabilities of soils that are important for various agricultural, environmental, nature protection, landscape architecture and urban applications. Soil can perform many functions and these include functions related to ...
. Unlike water or air, for which established standards have been set, soil quality is difficult to define or quantify.
Indicators of soil quality
Soil quality can be evaluated using the Soil Management Assessment Framework. Soil quality in agricultural terms is measured on a scale of
soil value (''Bodenwertzahl'') in
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
.
Soil quality is primarily measured by chemical, physical, and biological indicators because soil function cannot easily be measured directly.
Each of these categories comprises several indicators that provide insight into overall soil quality. There are very few soil quality monitoring systems that can provide near real-time information on these indicators but almost all of these systems are currently reported only to the research level.
Physical
The physical category of soil quality indicators consists of tests that measure soil texture, bulk density, porosity, water content at saturation, aggregate stability, penetration resistance, and more. These measures provide hydrological information, such the level of water infiltration and water availability to plants.
Chemical
Chemical indicators include pH and nutrient levels. A typical soil test only evaluates chemical soil properties.
Biological
Biological measures include diversity of soil organisms and fungi.
The movement and biological functions of soil organisms (including earthworms, millipedes, centipedes, ants, and spiders) impact soil processes such as the regulation of soil structure, degradation of contaminants, and nutrient cycling.
[Ruiz N, Lavelle P, Jiménez J. 2008. Soil macrofauna field manual. Food and Agriculture Organization. https://www.fao.org/3/i0211e/i0211e00.htm]
References
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Agronomy
Environmental science
Pedology