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Topsoil is composed of mineral particles and organic matter and usually extends to a depth of 5-10 inches (13–25 cm). Together these make a substrate capable of holding water and air which encourages biological activity. There are generally a high concentration of roots in topsoil since this is where plants obtain most of their vital nutrients.
Soil gases (soil atmosphere [1]) are the gases found in the air space between soil components. The spaces between the solid soil particles, if they do not contain water, are filled with air. The primary soil gases are nitrogen, carbon dioxide and oxygen. [2] Oxygen is critical because it allows for respiration of both plant roots and soil ...
Apart from the basic soil composition, which is constant at one location, soil thermal properties are strongly influenced by the soil volumetric water content, volume fraction of solids and volume fraction of air. Air is a poor thermal conductor and reduces the effectiveness of the solid and liquid phases to conduct heat.
soil type and structure. For example, sandy soil holds little water while clay soils have high water-retention rates; the amount of water used by the plants/crops; how much nitrate is already present in the soil. [3] The level of nitrous oxide (N 2 O) in the Earth's atmosphere is increasing at a rate of 0.2 to 0.3% annually.
Soil also functions by maintaining the quantity and quality of air by allowing CO 2 to escape and fresh O 2 to enter the root zone. [7] Pore spaces within soil can also absorb water and hold it until plant roots need it. The soil also moderates temperature fluctuation, providing a suitable temperature for the roots to function normally.
Contour buffer strips used to retain soil and reduce erosion. A buffer strip is an area of land maintained in permanent vegetation that helps to control air quality, soil quality, and water quality, along with other environmental problems, dealing primarily on land that is used in agriculture.
Agricultural soil science studies the chemical, physical, biological, and mineralogical composition of soils as they relate to agriculture. Agricultural soil scientists develop methods that will improve the use of soil and increase the production of food and fiber crops. Emphasis continues to grow on the importance of soil sustainability.
This is true of the more well-known soil animals as well, such as ants, earthworms and moles. But soils can often become saturated with water due to rainfall and flooding. Gas diffusion in soil slows (some 10,000 times slower) when soil becomes saturated with water because there are no open passageways for air to travel. When oxygen levels ...