Climate Change and Crop Production – SS3 Horticulture and Crop Production Lesson Note (First Term)

Climate change is a long-term shift in the average weather patterns of a place, such as its temperature and rainfall.

Behavioural objectives

1. Explain what climate change and adaptation mean.
2. State four ways in which climate change affects crop production.
3. Describe adaptation strategies based on the choice of crops, water management and soil care.
4. Explain how weather forecasting and crop insurance help farmers.

What is climate change?

Climate change is a long-term shift in the average weather patterns that farmers have relied on.

• Late or uneven rains: the rainy season starts late, stops early or breaks in the middle.
• Heatwaves: high temperatures last for many days or weeks.
• Floods: heavy storms wash over farmland and damage crops.

What causes climate change?

Climate change is caused mainly by extra greenhouse gases, such as carbon dioxide, trapping heat in the atmosphere.

• Burning fossil fuels: petrol, diesel and gas release carbon dioxide.
• Deforestation: fewer trees remain to absorb carbon dioxide.
• Bush burning: fires release carbon dioxide and smoke into the air.

What is adaptation in farming?

Adaptation is changing the way we farm so that crops still grow well when the weather changes.

• Crops depend on suitable temperatures and a steady water supply.
• Farmers adapt by choosing suitable seeds, managing water and caring for the soil.
• Adapting early is better than waiting for the weather to destroy the crop.

How does climate change affect crop production?

Climate change affects crops in four main ways: heat stress, unpredictable water, new pests and diseases, and soil erosion.

• Heat stress: long periods of high temperature kill pollen and make flowers drop, so little or no fruit or grain forms.
• Water unpredictability: a “false start” of the rains makes farmers plant, then a long dry spell kills the seedlings. Floods can also wash crops away.
• New pests and diseases: warm conditions help pests such as the fall armyworm to multiply and spread to new areas.
• Soil erosion: heavy rainstorms wash away the topsoil, the most fertile layer, and leave weak soil.

What are the adaptation strategies for farmers?

There are three main groups of adaptation strategies: changing what we plant, managing water and caring for the soil.

Strategy 1: What crop choices help farmers adapt?

Choosing the right seed is the first step in adaptation.

• Drought-tolerant varieties: improved maize and rice bred to cope with short dry spells. They are called stress-tolerant crops.
• Early-maturing crops: quick varieties, such as 60-day cowpea, are harvested before the rains stop.
• Diversification: growing different crops together, for example cassava with melon. If one crop fails, the other may survive.

Strategy 2: How does water management help farmers adapt?

Water management means saving and using well the water that is available.

• Water harvesting: catching run-off from heavy storms in small ponds or underground tanks for use in dry spells.
• Mulching: covering the soil with dried grass or plastic sheets. It keeps moisture in and stops the sun baking the soil hard.
• Drip irrigation: thin pipes deliver water straight to the root of each plant. It uses much less water than flooding the field.

Strategy 3: How does soil and land care help farmers adapt?

Soil and land care keeps the soil healthy, so that it holds water and nutrients well.

• Cover cropping: growing creeping crops such as sweet potato or mucuna between seasons. They shade the soil, reduce erosion and add organic matter.
• Agroforestry: planting trees around the farm. Trees act as windbreaks, and their roots hold the soil together during floods.
• Conservation tillage: little or no ploughing. Ploughing exposes the soil, dries it out and releases carbon dioxide (CO₂), so seeds are planted directly into small holes.

How do weather forecasting and crop insurance help farmers adapt?

Information and financial support help farmers prepare for climate risks and recover from losses.

• Weather forecasting: mobile apps and radio send early warning alerts about storms or drought. Farmers then choose when to plant, spray or harvest.
• Crop insurance: the farmer pays a small fee. If the crop fails because of flood or drought, money is paid back to buy seeds for the next season.

Which adaptation strategy answers which problem?

Each effect of climate change has one or more strategies that reduce the damage.

Evaluation

1. What is climate change?
2. What is adaptation in farming?
3. State four ways in which climate change affects crops.
4. Explain how mulching and drip irrigation help to save water.
5. Why do farmers plant early-maturing crop varieties?

Assignment

List three adaptation strategies under soil and land care and explain each one, then explain how weather forecasting and crop insurance help a farmer whose farm is hit by flood or drought.