DETERMINATION OF SOIL PH

The PH of the soil can be measured or determined by measuring the concentration or amount of H ions present in soil solution.

    This can be measured by two methods; which are
               1) The electrometric method
               2) The colourimetric nethod 

         THE ELECTROMETRIC METHOD
In this method of determining soil PH, PH meter used and hydrogen ions concentration balanced against a standard hydrogen electrode, then PH meter read. This method is more accurate than the colourimetric method

        THE COLOURIMETRIC METHOD

This method use dyes which develop different colours at different values of PH and laboratory kits used.

  Sufficient quantity of dyes solution added on the soil till it soaks slowly through it. The colour of the mixture  dye and soil then compared with colours on a standard colour chart which shows the PH values of solution of different colours.

                   IMPORTANCE OF SOIL PH
     1) The solubility of different substance in a soil depends on PH of the soil.
     2) Sol pH determine the availability of nutrients of plant roots.
     3) soil pH has effect on the gorwth of soil organisms.

EFFECT OF SOIL PH ON AVAILABILITY AND SOLUBILITY OF PLANT NUTRIENTS.

 1) Effect on aluminium, Iron, Manganes and Boron
      Aluminium, manganes and magnesium are highly soluble in love soil pH there fore easily absorbed by palnt roots. But some times are soluable that can be toxic to some plants.

                                                                         

 2) Effect on calcium and magnesium.
    Calcium and magnesium are high in concentration at basic soil and deficient in acidic soil.
        There fore the soil with high concentration of OH ions means the soil basic and concentration of calcium and magnesium is high at that soil. And if the soil is highly concentrated with acid means concentration of H ions is high and concentration of tration of magnesium and calcium is low at that soil.

3) Effect on phosphorous.
      Phosphorous found in soil as H2PO4 or HPO4. PH of soil determine the type of phosphorous ions found in a given soil. When soil pH is high the phosphorous occur mainly in the form of HPO4 and if soil pH is low phosphorous occur mainly in the form of H2PO4.

  EFFECT OF SOIL PH ON SOIL ORGANISMS.

         Organisms live and function well in soil at a certain value of soil pH, however most soil organisms live well in soil pH of neutral or slightly acid.