What is cation exchange capacity PDF?
Cation exchange capacity (CEC) is the total capacity of a soil to hold exchangeable cations. It influences the soil’s ability to hold onto essential nutrients and provides a buffer against soil acidification. Soils with a higher clay fraction tend to have a higher CEC.
What is cation exchange capacity?
Cation exchange capacity (CEC) is a fundamental soil property used to predict plant nutrient availability and retention in the soil. It is the potential of available nutrient supply, not a direct measurement of available nutrients.
How do you calculate soil cation exchange capacity?
To determine the cation exchange capacity (CEC), calculate the milliequivalents of H, K, Mg, and Ca per 100g of soil (meq/100g soil) by using the following formulas: H, meq/100g soil = 8 (8.00 – buffer pH) K, meq/100g soil = lbs/acre extracted K ÷ 782. Mg, meq/100g soil = lbs/acre extracted Mg ÷ 240.
What is a good cation exchange capacity for soil?
The five exchangeable cations are also shown in soil test results as percentages of CEC. The desirable ranges for them are: calcium 65–80% of CEC, magnesium 10–15%, potassium 1–5%, sodium 0–1% and aluminium 0%.
What is a cation in soil?
Cation exchange. The ‘soil cations’ essential for plant growth include ammonium, calcium, magnesium, and potassium. There are three additional ‘soil cations,’ which are not essential plant elements but affect soil pH. The additional ‘soil cations’ include sodium, aluminum and hydrogen.
What is anion exchange capacity of soil?
Anion exchange capacity (AEC) represents the positive charge available to attract anions in solution. In most soils CEC > AEC. Influence of soil solution pH on CEC and AEC. Permanent charge is due to isomorphic substitution and pH-dependent charge is due to broken edges of clay minerals and OM surface.
What is effective cation exchange capacity?
The effective cation exchange capacity (CEC eff.) is a measure that integrates information about available soil surfaces to which metal cations are retained. originates from exchangeable calcium, whereas in acidic soils exchangeable aluminum contributes between 21 and 44% of the CEC eff.
What is the unit of CEC?
CEC is measured in millequivalents per 100 grams of soil (meq/100g). A meq is the number of ions which total a specific quantity of electrical charges.
What is cation exchange capacity CEC of soil?
The total number of cations a soil can hold–or its total negative charge–is the soil’s cation exchange capacity. The higher the CEC, the higher the negative charge and the more cations that can be held. CEC is measured in millequivalents per 100 grams of soil (meq/100g).
What affects cation exchange capacity?
Factors influencing the cation exchange capacity of soils Factors influencing the CEC include the soil type, the soil pH and the soil organic matter content. Similar to clay particles, organic matter have negatively charged sites which attract and hold on to cations.
What is soil cation?
The relative ability of soils to store one particular group of nutrients, the cations, is referred to as cation exchange capacity or CEC. Soils are composed of a mixture of sand, silt, clay and organic matter. Both the clay and organic matter particles have a net negative charge.