3. Improvement In Food Resources
Nutrient management :
Like other living organisms, plants also require nutrients for building their structure and maintaining their body functions. The plants require inorganic elements, which they chiefly obtain from the soil, where these elements occur in the form of minerals. Besides soil, the nutrients are also supplied to plants by air and water. The major elements supplied by air are carbon and oxygen. The hydrogen comes mainly from water. Soil is the main source to supply rest of essential elements to plants. There are sixteen elements which are essential for plants. These are
1. Carbon, 2. Hydrogen, 3. Oxygen
4. Nitrogen 5. Phosphorus, 6. Potassium,
7. Calcium, 8. Magnesium, 9. Sulphur
10. Iron, 11. Manganese 12. Boron,
13. Zinc, 14. Copper,
15. Molybdenum 16. Chlorine.
Out of sixteen nutrient elements required by plants, Carbon and oxygen are supplied by air, Hydrogen is supplied by water and remaining thirteen (13) elements are supplied by soil. Six of these elements are required in large amounts. They are called macro-nutrients. The elements categorized as macronutrients are : Nitrogen, Phosphorus, Potassium, Calcium, Magnesium and sulphur. The remaining seven elements , required in trace or micro amounts, are called micronutrients. They are Iron, Boron, Zinc, Copper, Molybdenum and Chlorine.
Nutrients Supplied by air, water and soil. Source Nutrients Air
Soil Carbon, Oxygen
(i) Macronutrients. Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, Sulphur.
(ii) Micronutrients. Iron, Manganese, Boron, Zinc, Copper, Molybdenum, Chlorine. To overcome the problem of deficiency of mineral nutrients and to increase the yield, the soil can be enriched by supplying these nutrients from the external sources. The major materials which are added into the soil to improve and maintain its fertility are grouped under two broad categories :