Fertilizer and Manure Application – SS1 Horticulture and Crop Production Lesson Note (Second Term)

Why Do We Feed Plants?

Just as you need food to grow tall and stay healthy, plants need nutrients from the soil. In Horticulture, we grow crops very intensively, which means the plants quickly “eat up” all the food in the soil.

To keep the plants healthy, we must put that food back. We do this using Fertilizers and Manures.

The Big Three (NPK)

Most plant food contains three main “ingredients”:

1. Nitrogen (N): For green, healthy leaves.
2. Phosphorus (P): For strong roots.
3. Potassium (K): For big fruits and fighting diseases.

If your soil is missing these, your harvest will be poor.

Organic Manure (The Natural Way)

Organic Manure comes from living things—plants and animals. This is the oldest and most “natural” way to farm.

Types of Manure:

• Poultry Droppings: Very common in Nigeria. It is very “strong” and must be allowed to cool (decompose) before use, or it might burn the plants.
• Cow Dung: Great for improving the soil’s ability to hold water.
• Compost: This is “black gold.” It is made by piling up kitchen waste, dried leaves, and grass and letting them rot into a rich, dark soil.
• Green Manure: Planting crops like beans and plowing them back into the soil while they are still green.

Why use Manure?

• It stays in the soil for a long time (up to 2-3 years).
• It improves the soil structure, making it soft and crumbly.
• It is usually free or very cheap if you have animals.

Inorganic Fertilizer (The Fast Way)

Inorganic Fertilizers (often called “Chemical Fertilizers”) are man-made in factories. They are like “vitamins” for the soil.

Common Types:

• NPK 15-15-15: The most popular one in Nigeria. It contains equal parts of Nitrogen, Phosphorus, and Potassium.
• Urea: Looks like white sugar. It is very high in Nitrogen and makes plants turn deep green almost overnight.
• Sulphate of Ammonia: Used to provide Nitrogen and also help plants in certain soil types.

Pros and Cons:

• Pros: They work very fast. If your plant is dying of hunger, chemical fertilizer is the “emergency medicine.” They are also easy to carry in bags.
• Cons: They can wash away easily with rain. If you use too much, you can “burn” and kill your crops. They don’t improve the soil structure like manure does.

Methods of Application (How to Feed)

How you give the food is just as important as what you give. You don’t just throw fertilizer randomly!

1. Broadcasting

You scatter the fertilizer evenly over the whole field by hand.

• Best for: Grains or crops planted very close together.

2. Ring Application

You dig a small circular trench around the plant (a few centimeters away from the stem) and pour the fertilizer inside, then cover it with soil.

• Best for: Tree crops like Oranges or Cocoa, and single plants like Peppers.

3. Row/Side Dressing

You apply the fertilizer in a straight line along the rows of your crops.

• Best for: Crops planted in clear lines like Maize or Okra.

4. Foliar Application

You dissolve the fertilizer in water and spray it directly onto the leaves.

• Best for: Giving a quick boost to flowers or vegetables.

The Golden Rules of Application

To be a successful horticulturist, follow these “Pro-Tips”:

1. Don’t Touch the Stem: Never let fertilizer touch the actual stem or leaves of the plant (unless it’s the foliar spray). It is very salty and will “burn” the plant skin.
2. Watering is Essential: Fertilizer needs water to dissolve so the roots can drink it. Always apply fertilizer when the soil is moist, or water the plants immediately after.
3. The “Little and Often” Rule: It is better to give a small amount of fertilizer twice than a huge amount once.
4. Cover it Up: After applying fertilizer on the soil, cover it with a little dirt. This prevents the sun from “stealing” the nutrients into the air (evaporation).

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