What are Fertilizers? (MCQs + FAQs)

Early History of Fertilizers

Agriculture has been among the oldest industry known to man. Using manure as fertilizer goes back to the start of farming. Since 5000 B.C, the Chinese have been utilizing animal manure in their fields. Manure is an organic material utilized to fertilize the land and it normally consists of faeces and urine of domestic livestock.

The very first prerequisite to using fertilizers was an understanding of the function of plant nutrients in plant development. Compounds of these elements particularly nitrogen, phosphorus and potassium are considered to be the most essential nutrients essential for plant growth. The components, like sulphur, magnesium and calcium are thought-about of secondary importance.

The requirement of a Fertilizer

Every compound of the desired elements cannot be a fertilizer. The desired elements need to exist in the substance in a water-soluble kind (so that the plant can take it up) readily available to the plants. The compound used as fertilizer should be stable in the soil in addition to in storage e.g., it must not be deliquescent or set to hard stony materials with time. Above all, it needs to be cheap to make.

Necessary Qualities of a Great Fertilizer

The important requisites of excellent fertilizer are:

1. The nutrient elements present in it should be readily available to the plant.
2. It must be fairly soluble in water so that it thoroughly blends with the soil.
3. It ought to not be injurious to plant.
4. It ought to be cheap.
5. It should be steady so that it is readily available for a longer time to the growing plant.
6. It needs to not modify the pH of the soil.
7. By rain or water, it should be converted into a form, which the plant can assimilate easily.

Classification of Fertilizers

Fertilizers are classified according to the nature of the elements like nitrogen, phosphorus and potassium which they supply to the soil. This classification offers the following kinds of fertilizers.

• i) Nitrogenous fertilizers
• ii) Phosphatic fertilizers
• iii) Potassium fertilizers.

Nitrogenous Fertilizers

These fertilizers supply nitrogen to the plants or soil. Nitrogen is required throughout the early stage of plant growth for the development of stems and leaves. It is the primary constituent of protein, imparts a green colour to the leaves and boosts the yield and quality of the plants. A few of the examples of nitrogen fertilizers are: – ammonium sulphate, calcium ammonium nitrate, fundamental calcium nitrate, calcium cyanamide, ammonia, ammonium nitrate, ammonium phosphate, ammonium chloride and urea.

(i) Ammonia (NH₃) as a Fertilizer

Ammonia is used in a liquid state while all the other fertilizers are utilized in the solid form. All the nitrogen fertilizers except calcium nitrate, sodium nitrate and potassium nitrate make the soil acidic however this level of acidity can easily be managed through liming of the soil (by the addition of lime) at regular periods. Liquid ammonia has actually become a crucial fertilizer for direct application to soil. It consists of 82% nitrogen and it is injected about 6 inches under the surface area of soil to prevent it from permeating out.

(ii) Urea (NH₂– CO – NH)

Urea is a high-quality nitrogenous fertilizer. It contains about 46% nitrogen and is the most concentrated strong nitrogen fertilizer. The main function of Urea fertilizer is to offer the plants with nitrogen to promote green leafy development and make the plants look rich. Urea also assists in the photosynthesis process of plants. Because urea fertilizer can provide only nitrogen and not phosphorus or potassium, it’s mostly used for flower development.

(iii) Ammonium Nitrate (NH₄NO₃)

It is manufactured by the neutralization reaction between ammonia and nitric acid as given below.

After neutralization, the water is vaporized. The strong ammonium nitrate is melted and after that sprayed below a tall tower. The falling beads are dried by an upward current of air. The fertilizer strengthens as tiny, hard pellets called prills. Prills of fertilizers are without dust, simple to deal with and easy to spread on the field. Ammonium nitrate contains33.5% nitrogen.

It is a beneficial fertilizer for lots of crops other than paddy rice since the microbial germs in flooded fields decays it to nitrogen gas. It is likewise used in mix with limestone. It is hygroscopic in nature.

Phosphatic Fertilizers

These fertilizers offer phosphorus to the plants or soil. Phosphorus is required to promote early growth to speed up the seed and fruit formation throughout the later stages of development. It likewise increases resistance to diseases. The numerous phosphatic fertilizers have different structures, due to which they have different solubilities. The two crucial water-soluble fertilizers are very phosphate (calcium superphosphate) Ca(H₂PO₄) 2and triple phosphate (diammonium- phosphate (NH₄) ₂HPO₄)

(i) Diammonium Phosphate (NH₄) ₂HPO₄

This substance of fairly high pureness is prepared by a continuous process that consists of reacting anhydrous ammonia gas and pure phosphoric acid at 60 – 70 ° C and pH 5.8 – 6.0.

It is an exothermic response. The heat of response vaporizes water from the alcohol and the crystals of diammonium phosphate are gotten, centrifuged, cleaned and dried. It contains 16% nitrogen and 48% P2O5. This product consists of about 75% plant nutrients and is deemed appropriate for usage either alone or in blended with other fertilizers.

Potassium Fertilizers

These fertilizers offer potassium to the plant or soil. Potassium is required for the development of starch, sugar and the fibrous material of the plant. They increase resistance to diseases and make the plants strong by helping in healthy root development. They also help in the ripening of seeds, fruits and cereals. Potassium fertilizers are particularly beneficial for tobacco, coffee, potato and corn.

(i) Potassium Nitrate (KNO₃)

On an industrial scale, it is prepared by the double decomposition reaction between salt nitrate and potassium chloride.

A concentrated hot solution of sodium nitrate is prepared and strong potassium chloride is added into it. On heating, the potassium chloride crystals become sodium chloride crystals, and the hot potassium nitrate is passed through the sodium chloride crystals at the bottom of the kettle. A little water is added to prevent more deposition of sodium chloride as the solution is cooled, which results in an excellent yield of pale yellow solid potassium nitrate. It contains 13% nitrogen and 44% potash.

MCQs about Fertilizers

 

Frequently Asked Questions (FAQs) About Fertilizers