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In agriculture, leaching is the loss of water-soluble plant nutrients from the soil, due to rain and irrigation. Soil structure , crop planting, type and application rates of fertilizers , and other factors are taken into account to avoid excessive nutrient loss.
Leaching is controlled largely by the hydraulic conductivity of the soil, which is dependent on particle size and relative density that the soil has been consolidated to via stress. [4] Diffusion is controlled by other factors such as pore size and soil skeleton, tortuosity of flow path, and distribution of the solvent (water) and solutes.
Nutrients in the soil are taken up by the plant through its roots, and in particular its root hairs.To be taken up by a plant, a nutrient element must be located near the root surface; however, the supply of nutrients in contact with the root is rapidly depleted within a distance of ca. 2 mm. [14] There are three basic mechanisms whereby nutrient ions dissolved in the soil solution are brought ...
The most abundant ion in plant cells is the potassium ion. [2] Plants take up potassium for plant growth and function. A portion of potassium uptake in plants can be attributed to weathering of primary minerals, but plants can also ‘pump’ potassium from deeper soil layers to increase levels of surface K. [2] Potassium stored in plant matter can be returned to the soil during decomposition ...
[12] [17] [18] N saturation can result in nutrient imbalances (e.g., loss of calcium due to nitrate leaching) and possible forest decline. [13] A 15-year study of chronic N additions at the Harvard Forest Long Term Ecological Research program has elucidated many impacts of increased nitrogen deposition on nutrient cycling in temperate forests.
Owing to irregular distribution of salt in the soil or to irregularity of the soil structure (figure 2), the leaching efficiency (E L) can be different from unity. Soils with a low leaching efficiency are difficult to reclaim. In the Tagus delta, Portugal, the leaching efficiency of the dense clay soil was found as low as 0.10 to 0.15. [4]
The specific heat of pure water is ~ 1 calorie per gram, the specific heat of dry soil is ~ 0.2 calories per gram, hence, the specific heat of wet soil is ~ 0.2 to 1 calories per gram (0.8 to 4.2 kJ per kilogram). [90] Also, a tremendous energy (~584 cal/g or 2442 kJ/kg at 25 °C) is required to evaporate water (known as the heat of ...
Microbial soil enzymes may release nutrients from minerals or organic matter for use by plants and other microorganisms, sequester (incorporate) them into living cells, or cause their loss from the soil by volatilisation (loss to the atmosphere as gases) or leaching. [46]