How to Manage Alkaline Soil? 7 Ways

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How to Manage Alkaline Soil? 7 Ways


Alkaline Soil:

Alkaline soil has a pH greater than seven (>7). It is common in Arid and Semi-arid climates. Almost 25% of the soils on the earth’s surface are alkaline in nature. It is rich in calcium carbonate (CaCO3) and has a high porosity and is freely draining.     




Characteristics of Alkaline Soil:

  • Electrical conductivity (EC) 4 mmhos.cm-1.
  • Exchangeable Sodium Percentage (ESP) is 15.

Classification of Alkaline Soil:

Alkaline soil can be classified into the following types:

  1. Saline alkali Soil: Alkali soil that contains salts in excess are known as Saline Alkali Soil.
  2. Non-Saline Alkali Soil: Alkali soil that does not contain soluble salts are called non-saline alkali soil.
  3. Degraded alkali Soil: When the clay complex of some alkali soil undergoes degradation, the resulting soil is called degraded alkaline soil.

Causes of High pH:

The factors that contribute to soil alkalinity are the following:

  • Area that receive little rainfall may have alkaline soil.
  • If the water that is used for irrigation purposes contains alkaline substances i.e. calcium carbonate or magnesium carbonate.
  • The soil may have alkaline nature.
  • Newly cultivated soil tends to be alkaline because calcium and other substances are pulled from lower horizons.   

 Effects of Soil High pH:

  • High pH causes reduction in the availability of nutrients like phosphorus (P) and micronutrients i.e. zinc (Zn), copper (Cu), manganese (Mn), iron (Fe).
  • Also due to high sodium or sodic soil, drainage issues are caused.   


Amendments to Manage Alkaline Soil:

There are some amendments and practices that can help decrease the pH or reduce the alkalinity of the soil. However, such amendments should not be added to soil unless soil is properly tested.  

  1. Incorporate Organic Matter into the Soil: After its incorporation, the organic matter decomposes and acidic reactions occur that help reduce pH. As a result drainage and aeration are improved.  

  1. Use Humic acid: Regular use of Humic acid helps in the stimulation of biological activities that are involved in mineralization and decomposition of organic matter. As a result of which organic acids are produced.  
  2. Application of Sulfur or Sulfur-coated urea: Application of sulfur or sulfur-coated urea will also be helpful to manage alkaline soil.
  3. Sufficient supply of water: If the supply of water is sufficient, the concentration of the alkalinity in the soil would remain low. Therefore, in alkaline soil, moisture should be kept at optimum field capacity.  
  4. Use of acidic fertilizer: Fertilizers that have acidic nature should be used. E.g. Ammonium nitrate, Ammonium sulfate, and Urea.
  5. Use of organic manures: Due to the high water-holding capacity of organic manures, they, if added to soil, increase the water holding capacity of soil as well. It results in low conductivity of soil solution.  
  6. Ploughing and levelling of land­: Land should be regularly ploughed and levelled. It would help increase the infiltration and percolation of the land. This way alkaline substances may leach down.  
  7. Prevention of water evaporation: Since water shortage causes increase in alkalinity, therefore, water evaporation should be prevented to conserve moisture.  

 Conclusion:

It is concluded that prior to the application of the amendments, soil pH must be tested. It should also be noted that majority of the soils are suffering from the soil alkalinity. Besides, since it is a persistent problem therefore it should be treated as a long-term project. The above mentioned amendments (Humic acid, organic manure, acidic fertilizers and sulfur) as well as practices (Sufficient supply of water, controlling water evaporation and ploughing of land) will be helpful in the management of the alkaline soils.     

 

 

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