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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.
Irrigation using water with high sodium adsorption ratio may require soil amendments to prevent long-term damage to the soil. [3] If irrigation water with a high SAR is applied to a soil for years, the sodium in the water can displace the calcium and magnesium in the soil. This will cause a decrease in the ability of the soil to form stable ...
[15] k 1 is the rate constant for chemical uptake from water at the respiratory surface (L*kg −1 *d −1). [15] C WD is the chemical concentration dissolved in water (g*L −1 ). [ 15 ] k 2 ,k E ,k G ,k B are rate constants that represent excretion from the organism from the respiratory surface, fecal excretion, metabolic transformation, and ...
The Richards equation represents the movement of water in unsaturated soils, and is attributed to Lorenzo A. Richards who published the equation in 1931. [1] It is a quasilinear partial differential equation; its analytical solution is often limited to specific initial and boundary conditions. [2]
The maximum rate at that water can enter soil in a given condition is the infiltration capacity. If the arrival of the water at the soil surface is less than the infiltration capacity, it is sometimes analyzed using hydrology transport models , mathematical models that consider infiltration, runoff, and channel flow to predict river flow rates ...
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]
Accumulation numbers in flat areas will be very large, so TWI will not be a relevant variable. The index is highly correlated with several soil attributes such as horizon depth, silt percentage, organic matter content, and phosphorus. [2] Methods of computing this index differ primarily in the way the upslope contributing area is calculated.