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Soil texture affects soil behaviour, in particular, its retention capacity for nutrients (e.g., cation exchange capacity) [8] and water. Sand and silt are the products of physical and chemical weathering of the parent rock ; [ 9 ] clay, on the other hand, is most often the product of the precipitation of the dissolved parent rock as a secondary ...
For a given soil, the greater the void ratio, the higher the value of the coefficient of permeability. Here 'e' is the void ratio. Based on other concepts it has been established that the permeability of a soil varies as e 2 or e 3 /(1+e). Whatever may be the exact relationship, all soils have e versus log k plot as a straight line. [2]
The decomposition of soil organic matter by microorganisms is another mechanism whereby the soluble pool of nutrients is replenished – this is important for the supply of plant-available N, S, P, and B from soil. [144] Gram for gram, the capacity of humus to hold nutrients and water is far greater than that of clay minerals, most of the soil ...
Pores (the spaces that exist between soil particles) provide for the passage and/or retention of gasses and moisture within the soil profile.The soil's ability to retain water is strongly related to particle size; water molecules hold more tightly to the fine particles of a clay soil than to coarser particles of a sandy soil, so clays generally retain more water. [2]
Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces. [1] Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the surrounding soil water. [ 2 ]
The approach of other soil labs also entering the soil health field is to add into common chemical nutrient testing a biological set of factors not normally included in routine soil testing. The best example is adding biological soil respiration ("CO 2 -Burst") as a test procedure; this has already been adapted to modern commercial labs in the ...
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.
Water retention curve is the relationship between the water content, θ, and the soil water potential, ψ. The soil moisture curve is characteristic for different types of soil, and is also called the soil moisture characteristic. It is used to predict the soil water storage, water supply to the plants (field capacity) and soil aggregate stability.