Soils 205- General Soils

Lecture 20- Altering soil pH

I.  Increasing pH

    a.  Liming materials:

        -Calcitic limestone:

        -Dolomitic limestone:

        -Quicklime:

        -Hydrated lime:

    b.  two step reaction:

    c.  Determination of lime requirement

    must consider:

    1)

    2)

    3)  The chemical composition of the liming materials

4)  The fineness (texture) of the liming material- The smaller the particle size, the faster the reaction rate.  In general, limestone with at least 50% of the particles small enough to pass through a 60-mesh screen (<0.25 mm in diameter) is satisfactory.

    d.  example problem:

    e.  special situations

        i.  forests-

        ii.  no till on acid soils-

        iii.  lawns, golf greens, turf grass-

II.  Decreasing soil pH

     a.  addition of Fe (FeSO₄)

    b.  addition of sources of sulfur