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Several factors affect the variation that exists in soil organic matter and soil carbon; the most significant has, in contemporary times, been the influence of humans and agricultural systems. Although exact quantities are difficult to measure, human activities have caused massive losses of soil organic carbon. [ 10 ]
Soil is made up of a multitude of physical, chemical, and biological entities, with many interactions occurring among them. It is a heterogenous mixture of minerals and organic matter with variations in moisture, temperature and nutrients. Soil supports a wide range of living organisms and is an essential component of terrestrial ecology.
Soil consists of a solid phase of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and water (the soil solution). [ 1 ] [ 2 ] Accordingly, soil is a three- state system of solids, liquids, and gases. [ 3 ]
The type and amount of vegetation depend on climate, topography, soil characteristics and biological factors, mediated or not by human activities. [104] [105] Soil factors such as density, depth, chemistry, pH, temperature and moisture greatly affect the type of plants that can grow in a given location. Dead plants and fallen leaves and stems ...
Soil that is healthy is fertile and productive. [29] But soil erosion leads to a loss of topsoil, organic matter, and nutrients; it breaks down soil structure and decreases water storage capacity, reducing fertility and water availability to plant roots. Soil erosion is, therefore, a major threat to soil biodiversity. [30]
Soil respiration is a key ecosystem process that releases carbon from the soil in the form of carbon dioxide. Carbon is stored in the soil as organic matter and is respired by plants, bacteria, fungi and animals. When this respiration occurs below ground, it is considered soil respiration. Temperature, soil moisture and nitrogen all regulate ...
Soil aeration maintains oxygen levels in the plants' root zone, needed for microbial and root respiration, and important to plant growth. Additionally, oxygen levels regulate soil temperatures and play a role in some chemical processes that support the oxidation of elements like Mn 2+ and Fe 2+ that can be toxic.
The benefits of SOM result from several complex, interactive, edaphic factors; a non-exhaustive list of these benefits to soil function includes improvement of soil structure, aggregation, water retention, soil biodiversity, absorption and retention of pollutants, buffering capacity, and the cycling and storage of plant nutrients.