Apart from water, sunlight and air, certain nutrients are also needed for the growth of plants. We know that the plants get their nutrients from the soil.
Nitrogen (N), Phosphorous (P) and Potassium (K) are the three important nutrients among the various nutrients needed for the growth of plants. These three are called as Principal Nutrients.
The table given below depicts the quantity of elements absorbed by certain common plants.
* What would happen to the nutrient content of the soil, if the field is farmed continuously?
* How could we resend these nutrients back to the soil?
Fertilizers are organic or inorganic materials that we add to the soil to provide one or more nutrients to the soil.
Fertilizers given to plants can be classified into two. They are organic and inorganic fertilizers.
Fertilizers containing only plant or animal-based materials or those synthesized by micro-organisms are called organic fertilizers.
These fertilizers can be prepared easily. This type of fertilizers are economical. (e.g)
Vermi compost, compost.
The fertilizers prepared by using natural elements by making them undergo chemical changes in the factories are called inorganic fertilizers. (e.g) Urea, Ammonium sulphate and Super phosphate.
The table given below lists the nutrients in inorganic fertilizers
If we use 50 kg of urea, then according to the table, 23 kg of nitrogen (46 percent) will be added to the soil.
* The percentage of nitrogen in ammonium sulphate is 21%
* If 50 kg of potassium nitrate is added to soil, how much potassium would the soil get? 22 kg
Earthworms take organic wastes as food and produce compost castings. So earthworms are known as Farmers' friends because of the multitude of services they provide to improve soil health and consequently plant health.
Activity 4: Make a visit to agriculture field in your area. List out the various crops and type of fertilizers used there.