Crops require sixteen essential nutrients to grow normally. Carbon, hydrogen and oxygen are derived from the air and make up more than 90 per cent of the fresh plant tissue. The remaining 13 nutrients are found in the soil and absorbed through the plant’s roots. A balanced supply of these nutrients is essential for a healthy plant growth. While Primary nutrients including Nitrogen, Phosphorus and Potassium are required in large amounts, Secondary nutrients such as Sulphur, Calcium and Magnesium are required in substantially smaller amounts.
The remaining nutrients are called the Micronutrients and comprises of Zinc, Boron, Copper, Iron, Molybdenum and Manganese. They are also referred to as Minor Nutrients as they are required in smaller quantities. The supply of these Micronutrients is as important as Macronutrients as they reinforce and supplement the robust plant growth as provided by Primary and Secondary Nutrients.
Through soil testing and analyses, micronutrient deficiencies have been verified in many soils. Survey and analyses of more than 2,50,000 soil samples across 20 States by All India Coordinated Research Project indicated deficiency of Zinc to be the highest at 49 percent, Boron at 33 per cent, 13 per cent in Iron followed by 7 and 4 per cent respectively in Molybdenum and Manganese. However the extent and severity of micronutrient deficiency may vary as per soil type, ecological zones and most importantly management and productivity of crops and cropping patterns.