kationinvaihdokyky

Kationinvaihdokyky is a Finnish term that translates to cation exchange capacity (CEC) in English. It refers to the ability of a material, typically soil or clay, to retain and exchange positively charged ions, known as cations. These cations are essential plant nutrients like calcium (Ca2+), magnesium (Mg2+), potassium (K+), and ammonium (NH4+). A higher cation exchange capacity means a material can hold more of these nutrients, making them available for plant uptake.

The CEC of a soil is primarily determined by the amount and type of clay minerals and organic matter present. Clay particles and organic matter have negatively charged sites on their surfaces. These negative charges attract and hold positively charged cations, preventing them from being leached away by water. When plants need these nutrients, they can release hydrogen ions (H+) or other cations from their root surfaces, which then displace the nutrient cations from the negatively charged sites on the soil particles.

Cation exchange capacity is an important soil property because it directly influences soil fertility and the efficiency of fertilizer use. Soils with low CEC, such as sandy soils, tend to have lower nutrient-holding capacity and are more prone to nutrient losses. Conversely, soils with high CEC, like clay soils or soils rich in organic matter, are generally more fertile and can support a wider range of plants. Understanding a soil's CEC helps in managing nutrient application and maintaining soil health.