Soil elements are the constituents of soil. The main constituents are classified into four categories. These are- 1) inorganic materials, 2) organic materials, 3) soil air and 4) soil water.
All the elements of soil are occupied in different portion in soil mass. It is estimestimated, average soils contain approximately 50% of void spaces and 50% of solids. The void spaces contains soil air and water. Again Soil solids include all organic and inorganic materials.
Plant nutrition are found in soil solution in the cationic and anionic forms. Those ions are available form of nutrients to be taken by the plants. The cations and anions are listed below:
- Cations: Na+, K+, Ca++, Mg++, Al+++, Fe++, Fe+++, Cu+, Cu++, Zn++, Hg+ etc.
- Anions:(NO3)-, (SO4)2-, (PO4)3-, (CO3)2-, (HCO3)- etc.
Process of Heavy Metal Contamination in Plants through Soil
Soil available water contains plant essential nutrients in ionic forms. These are Na+, K+, Ca++, Mg++, Al+++, Fe++, Fe+++, Cu+, Cu++, Zn++, Hg+ , (NO3)-, (SO4)2-, (PO4)3-, (CO3)2-, (HCO3)- etc.
All of those nutrients in a balanced proportion are important for plant’s optimal growth. For example, nitrogen deficit soil can cause “Chlorosis” disease and a stunt growth of the plant. All types of nutrient deficiencies can cause problems on plant’s growth.
Plants growing in polluted soils with high concentration of Pb , Hg, As, Cr etc. uptake these heavy metals also during photosynthesis. Although, they aren’t essential for plants, they are assimilated in the plant tissue.