Soil Fertility - Base Saturation and Cation Exchange Capacity
2019年12月17日 · To understand the theory behind the BCSR method or specifically, the Ca:Mg ratio, one must understand cation exchange capacity (CEC). Cations are positively charged ions in the soil solution (Ca 2+, NH 4+, Mg 2+, K +, Na +, etc.).
When a soil test indicates that fertilizer potassium is required, the rate of fertilizer recommended is intended to satisfy crop needs and build soil potassium levels to the optimum range. Sandy soils with very low CEC will tend to lose substantial quantities due to leaching and will require more frequent applications of fertilizer.
Fundamentals of Soil Cation Exchange Capacity (CEC)
Others like potassium are added regularly to soils as fertilizer for the purpose of being withdrawn as needed by crops. 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.
Thus, the CEC of a soil represents the total amount of exchangeable cations that the soil can adsorb. The cations used by plants in the largest amounts are calcium, magnesium, and potassium. In most soils within humid regions such as in New York, sodium is not present in sufficient quantities to occupy a significant amount of the CEC.
Soil Test Interpretation Guide | OSU Extension Service
Base saturation is the percentage of the soil CEC occupied by basic cations (calcium, magnesium, potassium, sodium) at the current soil pH value. Base saturation and CEC are nearly equivalent (base saturation is 100%) when soil pH is near 7. An acidic soil has a base saturation of about 50% when the soil pH is about 5.
Interpreting Test Results | Soil | Illinois Extension | UIUC
Cation Exchange Capacity, or CEC, indicates how well the soil can hold plant nutrients. The amount of organic matter, which has very high CEC, and the amount and type of clay minerals, which also has high CEC, affects the overall CEC in a soil. Soil with a CEC of 15 to 20 will be in good shape to hold nutrients.
Cation Exchange Capacity and Base Saturation
2014年2月26日 · Cation exchange capacity (CEC) is a measure of the total negative charges within the soil that adsorb plant nutrient cations such as calcium (Ca2+), magnesium (Mg2+) and potassium (K+). As such, the CEC is a property of a soil that describes its capacity to supply nutrient cations to the soil solution for plant uptake.
20.3: Cation Exchange Capacity (CEC) Management
2023年11月18日 · There are two practical ways to increase the ability of soils to hold nutrient cations such as potassium, calcium, magnesium and ammonium: Add organic matter by using the methods discussed in earlier chapters. If the soil is too acidic, use lime (see “pH Management”) to raise its pH to the high end of the range needed for the crops you grow.
(PDF) Soil CEC explained: understanding, measuring and using cation ...
2010年1月1日 · high levels of H+ or Al+++ is an acid soil, with a low pH. Magnesium, Potassium and Sodium. These are all alkaline cations, also called basic. cations or bases.
Estimating CEC Soil texture can be used to estimate CEC. A general rule of thumb is that organic matter % x 2 plus clay % x 0.5 equals CEC. For example, a soil with a three percent organic matter and 20% clay would be expected to have a CEC of 16 (3% OM x 2 + 20% Clay x 0.5).