Question

Which one of the following nutrients is not available in fertilizers?
a. Nitrogen
b. Phosphorous
c. Iron
d. Potassium

Answer 1

Hint: Fertilizer is a natural or artificial substance containing the chemical elements that improve the growth and productiveness of plants. Fertilizers can be categorized into inorganic and organic forms. Fertilizers have the required quantity of macro and micronutrients. The elements that plants require in relatively large amounts are macronutrients whereas micronutrients are those that plants require in much smaller amounts.

Complete answer:
- Fertilizers are nothing but natural and chemical manures.
- Fertilizers contain only nitrogen, phosphorus, and potassium nutrients in various forms.
- Fertilizers don’t contain any other macro or micronutrients that are necessary for the growth of a plant. They enhance the water retention capacity of the soil and also increase its fertility.
- In soil, Iron, it is often ineffective, especially in pH above 7.0, because iron quickly transforms to $F{e^{3 + }}$ and precipitates as one of the iron oxides.

Hence, the correct answer is option (C).

Additional information:
There are various advantages and disadvantages of the usage of fertilizers.
> The advantages of fertilizers are mentioned below:
- They are easy to transport, store, and apply.
- For supplying a specific nutrient, we can select a specific fertilizer due to its nutrient specific nature.
- They are water-soluble and can easily dissolve in the soil. Hence, they are easily absorbed by the plants.
- They have a rapid effect on the crops.

> Fertilizers have the following disadvantages:
- They are expensive.
- The ingredients in the fertilizers are toxic to the skin and respiratory system.
- Excessive use of fertilizers damages the plants and reduces soil fertility.
- Leaching occurs and the fertilizers reach the rivers causing eutrophication.

Note: Fertilizers provide three main macronutrients: Potassium, Nitrogen, and Phosphorous are normally which are consumed in larger quantities and derived from the soil in the form of inorganic salts and are nutrients available in fertilizers which make up 0.5 to 6.0 percent, are present in plant tissue, in quantities from 0.15% to 6.0% of a dry matter (DM) (0% moisture) basis. Iron is a micronutrient for plant growth which is not available in fertilizers.