Question

What are fertilizers? Excessive use of fertilizers is not advisable. Explain.

Answer 1

Hint:Excessive use of fertilizers can lead to the death of plants and microbiota living in the soil. This condition is also known as ‘fertilizer burn'.

Complete answer:
Fertilizers refer to the natural or synthetic material provided to the plant to fulfill all the nutrients required for their growth and development. They enhance the nutrition level in the plants. They also increase the water and oxygen holding capacity of the soil.
Excessive use of fertilizers proves detrimental to plant growth and the surrounding environment. Some of the harmful effects of fertilizers are-
- Eutrophication- The excessive fertilizer can be washed away by the falling rainwater into the nearby water bodies. This leads to the enrichment of water bodies with nutrients resulting in an abrupt and uncontrolled growth of algae (algal bloom) and weeds. This is known as eutrophication.
- Leaching- The excessive nitrogen gets converted into nitrates which can then be washed off to the water bodies or leached down by the earth. It leads to groundwater pollution.
- Acidification of soil- The accumulation of excessive elements like cadmium, fluoride, zinc, uranium, etc. can acidify the soil.
- The continuous use of NPK fertilizers can lead to a deficiency of micronutrients like iron, zinc, copper, magnesium, etc. in the plant.
- Loss of symbiosis: It hampers the symbiotic relationship between the root and mycorrhizal fungi.
- Greenhouse effect: The production of nitrogen fertilizers leads to the formation of greenhouse gases such as carbon dioxide, methane, and nitrous oxide.

Note:
- They are classified into straight fertilizers (consisting of either nitrogen, phosphorus, or potassium) and multi-nutrient fertilizers (containing two or more nutrients).
- The most common nitrogen-containing fertilizer is ammonia and ammonium nitrate. Yara International is the world’s leading nitrogen-based fertilizer manufacturing company.
- An excessive amount of nitrate (10mg/L) in the groundwater may lead to ‘blue baby syndrome'.