1.5-Adding Manure and Fertilisers

Manure and fertilisers are substances that are added to the soil to enhance its fertility and provide essential nutrients to plants for their proper growth. Manure is an organic substance, while fertilisers can be either organic or inorganic.

Manure

Manure is a natural substance obtained from the excreta of animals and plants. It is rich in nutrients and organic matter, which improves the structure of the soil, retains moisture, and increases microbial activity. There are two types of manure:

• Farmyard Manure (FYM): Composed of the mixture of cow dung, urine, and litter of bedding material.
• Compost: Made by decomposing plant and animal waste, either by aerobic or anaerobic processes.

Fertilisers

Fertilisers are chemical substances that are added to soil to provide nutrients to crops. They contain essential elements like nitrogen (N), phosphorus (P), and potassium (K), which are necessary for plant growth. Fertilisers can be classified into two main categories:

• Inorganic Fertilisers: These are chemical fertilisers manufactured in industries. Examples include urea, ammonium nitrate, and superphosphate.
• Organic Fertilisers: These are derived from plant or animal sources, such as manure, compost, and bone meal.

Important Nutrients for Plants

Plants require several nutrients for growth, but the most important ones are:

• Nitrogen (N): Helps in the development of leaves and stems. It is a key component of proteins and chlorophyll.
• Phosphorus (P): Aids in root development and the production of flowers and seeds. It is an essential part of DNA and RNA.
• Potassium (K): Important for overall plant health. It helps in the regulation of water and supports the functioning of enzymes.

Advantages of Manure and Fertilisers

Adding manure and fertilisers to the soil provides several benefits:

• Increases the availability of nutrients in the soil.
• Improves soil structure and water retention capacity.
• Enhances crop yield by providing essential nutrients for growth.
• Supports better root development and plant health.

Application of Fertilisers

Fertilisers should be applied in the correct manner to avoid any harm to the soil and plants. Overuse of fertilisers can lead to soil degradation, water pollution, and nutrient imbalances. Fertilisers can be applied through:

• Basal Application: Fertilisers are mixed with soil before sowing seeds.
• Top Dressing: Fertilisers are applied to the soil surface after the plants have started growing.
• Foliar Application: Fertilisers are sprayed on plant leaves for quick nutrient absorption.

Formulae for Fertiliser Composition

The composition of fertilisers is often expressed as a ratio of nitrogen, phosphorus, and potassium. For example, a fertiliser labelled as 20:10:10 means it contains 20% nitrogen, 10% phosphorus, and 10% potassium.

For a balanced fertiliser, the general formula is:

$N + P + K = Nitrate \, (NO_3^-) + Phosphate \, (PO_4^{3-}) + Potassium \, (K^+)$

Important Points

• Manure is natural and slow-acting, while fertilisers are quick-acting but may degrade the soil over time if used excessively.
• Manure improves soil texture, whereas fertilisers only provide essential nutrients.
• Overuse of fertilisers can lead to soil pollution and affect plant health.