Formation of Alkali soils

Formation of Alkali soils
    1. Sodication due to repeated cycles of wetting & drying.
    2. Sodication due to shallow brackish ground waters.
    3. Sodication due to the use of high RSC water.
    4. Sodication due to the use of saline irrigation waters low in Cl: SO4 ratio.
  • In contract to saline soils the saturation extract of alkali soils contains measurable amounts of CO32- and HCO3-; C1- and SO42- may also be present in appreciable amounts. Among the cations, sodium (Na+) is the dominant one followed by Mg2+ and Ca2+.
    Sodicity classification according to the FAO

    Class

    ESP

    Description

    a.

    <10

    Sodic free soil

    b.

    10-20

    Slightly sodic

    c.

    20-30

    Moderately sodic

    d.

    30-50

    Straggly sodic

    e.

    >50

    Very sodic

Last modified: Saturday, 3 December 2011, 7:15 AM