Plant nutrients are one of the environmental factors essential for crop growth and development. Nutrient management is crucial for optimal productivity in commercial crop production. The nutrients in concentrations of 100 parts per million (ppm) in plant tissues are described as micronutrients and comprising of Zinc (Zn), Iron (Fe), Manganese (Mn), Boron (B), Copper (Cu), Chlorine (Cl), Molybdenum (Mo), and Nickel (Ni). Low mineral content adversely affecting plant, animal and human health.
Deficiency of above elements has been noticed in Indian sub continent. When a soil is deficient in micronutrient, plant grown on it will face deficiency of that particular micronutrient and can express symptoms called deficiency symptoms. Deficiency symptoms can be useful in recognizing something is wrong with the plant and can be treated with proper supplement. Deficiency of micronutrients during the past three decades has grown in both magnitude and extent because of increased use of high analysis fertilizers, use of high yielding crop varieties and increase in cropping frequency. This has become a major constraint for production and productivity.
All these years, recommendation of multi micronutrients was being made only on the basis of controlling deficiency symptoms in crops but now agriculture requires multi micronutrients as one of the regular inputs. Remarkably this should be considered with regular use of major nutrients (primary) in increase the quality of yield along with this the scientists concerned should also recommend multi micronutrients depending upon the requirement for different crop and plant growth stages.
The role and deficiency symptoms of micronutrients in plant:
Zinc (Zn) needed for the production of important plant hormones, like auxin. It is involvement for cell division, growth and production of outer coat of grains (husks).
Zinc deficiency results in stunted growth, lessened internodes length, young leaves are smaller than normal.
Iron (Fe) assists in biological process and cell growth in plants. Iron is a component of enzymes, essential for chlorophyll synthesis, photosynthesis the process whereby plants use sunlight for growth.
Iron deficiency leads to chlorosis or yellowing between the veins of new leaves.
Manganese (Mn) performs an important role in photosynthesis, chloroplast production, a cofactor in many plant reactions and activates enzymes.
Manganese deficiency cause chlorotic mosaic patterns on leaves.
Boron (B) enhances flowering blooms and develops uniform ripening process and it is essential in sugar transport, cell division and amino acid production.
Boron deficiency results in light general chlorosis, a death of growing point, deformed leaves with areas of discoloration.
Magnesium (Mg) plays a key role in the photosynthesis, cell division, synthesis of carbohydrates, proteins, fats, and vitamins.
Magnesium deficiency leads to chlorosis, interveinal chlorosis (yellowing of leaf with the veins remains green) poor and stunted plant growth.
Copper (Cu) stimulates enzymes required for photosynthesis.
Copper deficiency results in light overall chlorosis, leaf tips die back and tips are twisted, loss of fluid content in young leaves.
Sulphur (S) is recognized in forming proteins, enzymes, vitamins, and chlorophyll in plants and plays a crucial role in nodule development and efficient nitrogen fixation in legumes.
Sulphur deficiency symptoms appear on younger leaves and plants are small and their growth is stunted. The deficiency also observed on leaves turn pale yellow, older growth stays green, leaf veins lighter than surrounding area.
Molybdenum (Mo) is crucial for the growth of leaves and prevention of diseases in plants and it is involved in nitrogen metabolism, essential in nitrogen fixation by legumes.
Molybdenum deficiency is similar to those of ordinary nitrogen deficiency, general chlorosis (yellowing) of young plants, chlorosis of oldest leaves.
Except for Molybdenum other micronutrients are considered weakly mobile or immobile in plants. This means that deficiency symptoms appear severely on newest plant tissues, whereas for Molybdenum deficiency symptoms appear
first on oldest plant tissues.