Question

Which one of the following element is not an essential micronutrient for plant growth
(a)Mn
(b)Zn
(c)Cu
(d)Ca

Answer 1

There are 7 main plant nutrient elements that are defined as micronutrients they are: boron (B), zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), molybdenum (Mo), chlorine (Cl). In total, they constitute less than 1% of the dry weight of most plants.

Complete answer:
Micronutrient deficiencies can be in many soils even after frequent soil testing and plant analyses. Some reasons limiting the additions of micronutrients include:
-High yield crop constantly removes micronutrients from the soil
-Increased use of high-analysis NPK fertilizers that contain lower quantities of micronutrients.
-Advances in fertilizer technology are considerably reducing the residual addition of micronutrients.
Carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur are essential macronutrients. Micronutrients are just as important as macronutrients, the only difference is that the amount required is very small.

Additional Information: Calcium, magnesium, and sulfur are vital to plant nutrients and are termed as “secondary” nutrients mainly because plants require them in smaller quantities than nitrogen, phosphorus, and potassium.
One of the primary functions of calcium in plant development is to provide structural support to cell walls. It also serves as a secondary messenger when plants are physically or biochemically stressed. Soils with favorable pH levels are normally not deficient in calcium. Acidic soils with less calcium are deficient for legumes, especially peanuts, alfalfa, clovers, and soybeans. Additional calcium may be required by limited root system crops such as tomatoes, peppers, and cucurbits. Soluble calcium is available as the calcium ion and is needed for peanuts at pegging time and for peppers and tomatoes to prevent blossom end rot.
So, the correct answer is ‘Calcium’.

Note: Biofortification (a process by which the nutritional quality of food crops is improved) of crop plants including improvement of vitamin and mineral levels through plant biotechnology is being used in many world regions. The main objective is to address micronutrient deficiencies in regions of poverty and malnutrition.