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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 ]
Buffer capacity falls to 33% of the maximum value at pH = pK a ± 1, to 10% at pH = pK a ± 1.5 and to 1% at pH = pK a ± 2. For this reason the most useful range is approximately p K a ± 1. When choosing a buffer for use at a specific pH, it should have a p K a value as close as possible to that pH.
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 ...
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.
Typically, at field capacity, air is in the macropores, and water is in the micropores. Field capacity is the optimal condition for plant growth and microbial activity. At a potential of −1500 kPa, the soil is at its permanent wilting point, at which plant roots cannot extract the water through osmotic diffusion. Soil waterways still ...
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 ...
When dissolved sodium in comparison with dissolved calcium and magnesium is high in water, clay soil swells or undergoes dispersion which drastically reduces its infiltration capacity. [ 1 ] In the dispersed [ clarification needed ] soil structure , the plant roots are unable to spread deeper into the soil due to lack of moisture.
Acid-neutralizing capacity or ANC in short is a measure for the overall buffering capacity against acidification of a solution, e.g. surface water or soil water.. ANC is defined as the difference between cations of strong bases and anions of strong acids (see below), or dynamically as the amount of acid needed to change the pH value from the sample's value to a chosen different value. [1]