Classification of crops
| Class | Examples |
|---|---|
| Cereals | Maize, rice, sorghum, millet, wheat |
| Legumes (pulses) | Beans, cowpeas, pigeon peas, groundnuts |
| Root and tuber crops | Cassava, sweet potatoes, yams, Irish potatoes |
| Oil crops | Sunflower, sesame, cotton seed, coconut |
| Fibre crops | Cotton, sisal |
| Beverage crops | Coffee, tea, cocoa |
| Fruits and vegetables | Banana, mango, tomato, cabbage, onion |
| Spices and cash crops | Cloves, pepper, tobacco, cashew nuts |
Crops can also be grouped by their life cycle: annuals finish their life in one season (maize, beans), biennials in two (carrot, cabbage seed) and perennials live for many years (coffee, banana, mango).
The needs of a crop
A crop needs light for photosynthesis, water, air (oxygen and carbon dioxide), warmth, nutrients from the soil and a support for the roots. The crop must be suited to the local climate and soil.
Stages of crop production
Spacing and plant population
Worked examplePlants per hectare
Maize is planted 75 cm between rows and 30 cm between plants (one plant per hole). Find the plant population per hectare.
- Convert to metres.
- Divide.
Answer: About 44 000 plants per hectare.
Try itPlant population
Choose the spacing between rows and between plants.
Key terms
- Cereal
- A grass grown for its grain.
- Legume
- A plant of the pea family with nitrogen-fixing nodules.
- Perennial
- A plant that lives for many years.
- Spacing
- The distance between plants.
Summary
- Crops are grouped as cereals, legumes, roots, oil, fibre, beverage and others.
- Crops need light, water, air, warmth and nutrients.
- The stages are preparation, planting, care, harvest, storage and sale.
- Plants per hectare = 10 000 ÷ (row spacing × plant spacing).