Oil Crops – SS2 Horticulture and Crop Production Lesson Note (Third Term)

Oil crops are plants whose seeds, fruits or nuts contain a high amount of natural fat that can be pressed out as vegetable oil.

• Uses of the oil: cooking, margarine, soap and body creams.
• Examples in this lesson: oil palm, coconut and sunflower.

Behavioural objectives

By the end of the lesson, students should be able to:

1. define oil crops and name three examples grown in Nigeria;
2. describe the varieties, nursery practice, spacing and harvesting of oil palm;
3. describe the planting material, planting method, spacing and harvesting of coconut;
4. describe the planting, spacing, bird control and harvesting of sunflower;
5. list the steps in processing oil from oil crops.

What are the types of oil crops?

Oil crops are grouped by life span into two types: permanent (tree) crops and annual crops.

• Permanent oil crops: trees that crop for many years, such as oil palm and coconut.
• Annual oil crops: plants that complete their life in one season, such as sunflower, groundnut, soyabean and beniseed (sesame).

How is oil palm grown?

The oil palm (Elaeis guineensis) is a permanent tree crop whose fruit gives palm oil and palm kernel oil.

• Useful parts: almost every part of the tree can be used or sold.
• Climate: it grows best in hot, rainy areas on deep, well-drained soil.

What are the varieties of oil palm?

There are three varieties of oil palm: Dura, Pisifera and Tenera.

• Dura: has a thick shell and a small oil content.
• Pisifera: has no shell, but the fruit bunches often fail or drop early.
• Tenera: a cross between Dura and Pisifera. It has a thin shell and plenty of oil, so most farmers plant it.

How is oil palm cultivated?

1. Pre-nursery: do not plant the seeds directly in the bush. Raise them in a pre-nursery for about 3 months.
2. Main nursery: move the seedlings to a main nursery for about 9 months until they are strong.
3. Transplanting: move them to the field at the start of the rainy season.
4. Spacing: plant at 9 m × 9 m in a triangular pattern. This stops the leaves from blocking each other’s sunlight.
5. Harvesting: cut the fresh fruit bunches (FFB) with a chisel, or a sickle on a long pole, when the fruits turn bright orange-red.

What products come from oil palm?

• Palm oil: red oil pressed from the mesocarp (the fleshy part of the fruit).
• Palm kernel oil: oil pressed from the kernel inside the shell.
• Palm wine: sap tapped from the tree.
• Broomsticks: made from the leaves.

How is coconut grown?

The coconut palm (Cocos nucifera) is a permanent tree crop whose dried kernel, called copra, gives coconut oil.

• Nickname: it is called the “Tree of Life” because many parts of it are useful.
• Where it grows: it tolerates salty conditions near the coast, but it also grows well inland.

How is coconut planted?

1. Choose the planting material: use a mature seed nut. Pick a heavy nut with water that splashes when you shake it.
2. Sow in a nursery: lay the nut on its side in a nursery bed and cover it partly with soil.
3. Watch for sprouting: a shoot (the “spear”) appears after some weeks.
4. Transplant: move the strong seedlings to the field after several months in the nursery.
5. Spacing: usually 7 m × 7 m or 9 m × 9 m.

How is coconut harvested?

• Green coconuts: picked young for the refreshing water inside.
• Brown (mature) coconuts: picked for the white meat, which is dried into copra and pressed for coconut oil.

How is sunflower grown?

Sunflower (Helianthus annuus) is a fast-growing annual herb with a large yellow flower head that produces oil-rich seeds.

• The oil source: the oil comes from the seeds in the centre of the flower head.
• Life span: it matures in about 3 to 4 months.

How is sunflower cultivated?

1. Planting: sow 2 to 3 seeds directly in the soil at a depth of about 3 cm.
2. Spacing: 60 cm between rows and 30 cm between plants.
3. Bird control: ripe seeds attract birds, as rice does. Cover the flower heads with light cloth or mesh as they ripen.
4. Harvesting: cut the heads when the back of the head turns brown and the yellow petals fall off.

How do the three oil crops compare?

Oil palm and coconut are permanent trees, while sunflower is an annual herb. The table shows the main differences.

Why are oil crops useful to farmers?

Oil crops give farmers income, long-term yield and a ready market.

1. Multiple income: one oil palm gives red oil, kernel oil, broomsticks and palm wine.
2. Long life: once planted, coconut and oil palm crop for many years.
3. Industrial demand: factories need vegetable oil to make biscuits, margarine, soap and paint.

How is oil processed?

Oil is processed from fruits or seeds in four main steps: cleaning, steaming or boiling, pressing and filtering.

1. Cleaning: remove dirt and stones.
2. Steaming or boiling: this softens the fruits or seeds.
3. Crushing or pressing: use a machine or a manual press to squeeze out the oil.
4. Filtering: this makes the oil clear and removes pulp and bits of shell.

Classroom discussion

Ask the students: “If you have a small backyard in a city, which of these three would be the easiest to grow? Why?”

Answer: Sunflower, because it is small, matures in 3 to 4 months and does not take up space like a large palm tree.

Evaluation

1. What are oil crops? Name the three examples in this lesson.
2. Name the three varieties of oil palm and say which one most farmers plant.
3. State the spacing used for oil palm and for sunflower.
4. List the four steps in processing oil.
5. Give two ways in which oil crops benefit farmers.

Assignment

1. Describe how a coconut seed nut is chosen and planted.
2. Explain how a sunflower farmer protects the crop from birds and how the farmer knows the flower heads are ready for harvest.