Soil Fertility and Nutrient management (1+1)

Importance of pH in plant nutrition

• The soil pH or soil reaction is the chemical properties/characteristics of the soil showing the degree of acidity, alkalinity or neutral condition of soil. The pH is having many roles in crop production and particularly in plant nutrition.

  1. It significantly influences other chemical as well as biological properties and also affect the availability of most of the chemical elements of importance to plants and microbes.
  2. The soil pH greatly affects the solubility of minerals.
  3. The soil pH determines the amount and type of nutrient element availability in soils.
       Eg : In strongly acidic soils (pH 4-5) usually have high and toxic concentration of soluble Al and Mn.
  4. The soil pH also influences plant growth by the effect of pH on activity of beneficial microorganisms.
  5. Soil pH affects the mobility of many pollutants in soil by influencing the rate of their biochemical breakdown, their solubility and adsorption to colloids.
  6. Better nutrient availability found at neutral pH (6.5-7.5) like N, P, K, S, Ca, Mg but in low pH acid soil toxicity of Fe, Al, Mn etc., and deficiency of P, Mo etc. while in saline and alkaline soils Fe, Mn, Zn and Cu may be deficient. Mo availability is more.
  7. It helps in recommendation of soil amendments and fertilizer applications.
  8. It is a good guide for predicting which plant nutrients are likely to be deficient.
  9. It determines the microbial activity and the rate of decomposition.
  10. Availability and mobility of both macro and micro nutrients in soil is greatly affected by soil pH.
  11. The pH level affects soil physical properties ex: dispersion of clays and formation of stable aggregate structure.
  12. Suitability of soil for crop production.