What does base saturation tell you?
Base saturation is calculated as the percentage of CEC occupied by base cations. Figure 2 shows two soils with the same CEC, but the soil on the right has more base cations (in blue). Therefore, it has a higher base saturation. Base saturation is closely related to pH; as base saturation increases, pH increases.
What does high base saturation mean?
Soils with high percent base saturation have a higher pH; therefore, they are more buffered against acid cations from plant roots and soil processes that acidify the soil (nitrification, acid rain, etc.). They contain greater amounts of the essential plant nutrient cations K+, Ca2+ and Mg2+ for use by plants.
What is cation exchange capacity and base saturation?
Cation exchange capacity (CEC) is a measure of the soil’s ability to retain and supply nutrients, specifically the positively charged nutrients called cations. If all the cations are basic and none are acidic, there would be a 100% base saturation and the soil pH would be close to 7 or neutral.
What is a good base saturation in soil?
Base Saturation for soils to be productive must be greater than 80%. A soil that has a Base Saturation of less than 40% will develop problems and it will be difficult for this field to produce a crop.
What is a good soil CEC?
Organic matter has a very high CEC ranging from 250 to 400 meq/100 g (Moore 1998). Because a higher CEC usually indicates more clay and organic matter is present in the soil, high CEC soils generally have greater water holding capacity than low CEC soils.
Why are they called base cations?
Just like a magnet, a positive charge is strongly attracted to a negative charge. When soil particles have a negative charge, the particles attract and retain cations. Ammonium, calcium, magnesium, potassium, and sodium are known as the ‘base cations,’ while aluminum and hydrogen are known ‘acid cations.
Is high CEC good for plants?
When a high CEC soil has good test levels, it offers a large nutrient reserve. However, when it is poor, it can take a large amount of fertilizer or lime to correct that soil test. A high CEC soil requires a higher soil cation level, or soil test, to provide adequate crop nutrition.
Is a high CEC good?
Is high CEC good or bad?
Larger CEC values indicate that a soil has a greater capacity to hold cations. These soils may benefit from split applications of several nutrients. The particular CEC of a soil is neither good nor bad, but knowing it is a valuable management tool.
Which cation is predominant in normal soil?
The five most abundant exchangeable cations in the soil are calcium (Ca++ ), magnesium (Mg++), potassium (K+), sodium (Na+) and aluminium (Al+++). Cations are held by negatively charged particles of clay and humus called colloids.
What are the cations in bases?
The major distinguishing characteristic of cations is their positive charge. Just like a magnet, a positive charge is strongly attracted to a negative charge. Ammonium, calcium, magnesium, potassium, and sodium are known as the ‘base cations,’ while aluminum and hydrogen are known ‘acid cations.
Why does CEC increase with pH?
The higher the pH of the surrounding solution, i.e. higher OH ion concentration more H ions are attracted from the OH bonds of the clay structure and the higher the CEC of the clay.
How is base saturation and base cation exchange capacity related?
Base saturation is calculated as the percentage of CEC occupied by base cations. Figure 2 shows two soils with the same CEC, but the soil on the right has more base cations (in blue). Therefore, it has a higher base saturation. Base saturation is closely related to pH; as base saturation increases, pH increases.
How are base cation saturation ratios used in BCSR?
In the BCSR system, soil cations are balanced according to varying ratios often stated as giving ‘ideal’ or ‘balanced’ soil. These ratios can be between individual cations, such as the calcium to magnesium ratio, or they may be expressed as a percentage saturation of the cation exchange capacity (CEC) of the soil.
How to calculate the percentage of base saturation?
The percentage base saturation is expressed as follows: %BS = [ (Ca2+ + Mg2+ + K+)/CEC] × 100 Depending on soil pH, the soil’s base saturation may be a fraction of CEC or approximately equal to CEC. In general, if the soil pH is below 7, the base saturation is less than CEC.
When does base saturation equal to CEC in soil?
Depending on soil pH, the soil’s base saturation may be a fraction of CEC or approximately equal to CEC. In general, if the soil pH is below 7, the base saturation is less than CEC. At pH 7 or higher, soil clay mineral and organic matter surfaces are occupied by basic cations, and thus, base saturation is equal to CEC.