Fertilisers are substances added to the soil, which directly increase the productivity of the crop by supplying nutrients to the plant. Fertiliser sources can be both natural and man-made. These are essential for the growth and development of the plant. Their use increases the crop yield, improves water retention and increases the fertility of the soil, thereby enhancing the growth of plants.
The three main macronutrients (NPK) present in the fertiliser are:
- Nitrogen (N): Promotes the growth of leaves and plants.
- Phosphorus (P): Helps in the development of roots, flowers, seeds, and fruit.
- Potassium (K): Improves the stem growth and promotes flowering and the development of fruit.
Three secondary macronutrients present in the fertiliser are: Calcium (Ca), Magnesium (Mg), and Sulphur (S). Other micronutrients present are: Copper (Cu), Manganese (Mn), Iron(Fe), Molybdenum (Mo), Zinc (Zn), and boron (B).
Types of Fertilisers
Depending on the source from which it is produced, the types of fertilisers used in agriculture are classified into two types:
1. Inorganic Fertilisers
Inorganic fertilisers are chemical fertilisers that contain nutritional ingredients for crop growth and are produced by chemical processes. They contain a concentrated form of fertiliser that provides a ready source of nutrients to the crop. Inorganic fertilizers includes the following:
- Nitrogen Fertilisers: Provide nitrogen (N) for plant growth and help in leaf and stem development. Examples: Urea, Ammonium nitrate.
- Phosphorus Fertiliser: Helps in root development, flowering, and seed formation and is important for energy transfer in plants. Examples: Superphosphate.
- Potassium Fertiliser: Supplies potassium (K) and improves disease resistance and overall plant strength, and helps in water regulation. Examples: Potassium chloride, Potassium sulphate.
- Sulphur Fertiliser: Provides sulphur (S), which is important for protein synthesis and enzyme activity, and improves crop quality. Examples: Ammonium sulphate, Gypsum.
- Calcium Fertiliser: Supplies calcium (Ca) and helps in cell wall formation and root development, and also improves soil structure. Examples: Calcium carbonate, Calcium nitrate.
- Magnesium Fertiliser: Provides magnesium (Mg) and is essential for chlorophyll formation (photosynthesis). Examples: Magnesium sulphate.
2. Organic Fertilisers
- Organic fertilisers are those derived from plant and animal products.
- It adds carbonic chemicals to the soil, which are necessary for plant growth.
- It can be obtained from agricultural waste, livestock waste and industrial waste.
- Organic fertilisers improve soil organic matter content, boost microorganism growth, and alter the soil's physical and chemical properties.
- Examples of organic fertilisers are compost, manure, and bone meal. As compared to inorganic fertilizers it provides a slow release of nutrients to the plant. It contributes to the long-term health of the soil.
Biofertilizer
Biofertilizers are natural fertilisers containing living microorganisms, such as bacteria, fungi, or algae, that enhance soil fertility and plant nutrient absorption. Features of the biofertilizers include:
- They provide crucial nutrients to the soil, which help in the growth of plants.
- They help to increase the fertility of the soil.
- They fix atmospheric nitrogen and make it available to plants.
- It reduces reliance on chemical fertilisers.
- It ensures sustainable agriculture.
- Biofertilizers are symbiotically associated with the plant, and the interaction is (+,+).
- Their application enhances crop yield, quality, and resistance to diseases.
- Examples: Azotobacter, Rhizobium, blue-green algae.
Advantages of Fertilisers
The advantages of fertiliser are as follows:
- Fertilisers provide essential nutrients and promote plant growth, increasing the crop yield.
- It provides balanced nutrients to the soil.
- They are simple to apply, store and transport.
- Fertilisers ensure efficient absorption and utilisation as they directly provides nutrient to the plant.
- Ensures the livelihood of Farmers.
- They have a direct effect on the crops.
Disadvantages of Fertilisers
The disadvantages of fertilisers are as follows:
- They are expensive, and the fertiliser ingredients are toxic to the skin and respiratory system.
- Fertilisers can cause Soil Pollution.
- Fertiliser use may lead to soil acidification, nutrient imbalances, and reduced microbial activity.
- The fertilisers leak into the streams and cause eutrophication.
- Long-term use causes pH fluctuations in the soil.
- Crops that use excessive fertilisers can enter our food chain.
Importance of Fertilisers in Agriculture
Soil pollution or excessive usage of soil decreases the crucial nutrients and elements from the soil, which declines the productivity of the soil. Because the increasing population and the need for food requirements are increasing day by day, it is essential that the productivity of the soil stays above the threshold. Fertilisers play a very significant role in the following ways:
- Fertilisers have essential nutrients like nitrogen, which is essential for the formation of chlorophyll. Nitrogen also helps in the growth of the plant.
- Phosphorus strengthens the plant and helps in root growth and seed formation.
- Fertilisers containing potassium help in the regulation of stomata.
- Fertilizers provide essential nutrients to plants, helping them grow properly and remain healthy.