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South Africa is a country where water shortages occur frequently - NSC Agricultural Technology - Question 6 - 2017 - Paper 1
Question 6
South Africa is a country where water shortages occur frequently. Farmers must use more efficient irrigation systems to conserve water. A farmer wants to water one ... show full transcript
Worked Solution & Example Answer:South Africa is a country where water shortages occur frequently - NSC Agricultural Technology - Question 6 - 2017 - Paper 1
Step 1
Calculate the length and cost of the pipes you will need for the field.
Answer
To calculate the length of the pipes needed for the field, we have a closed network of pipes with a total area of 1 hectare, which is equivalent to 10,000 m². Given that the pipes are laid evenly across the field:
The total length of pipes will be calculated as follows:
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Length of pipes: Each pipe is 100 m long and connected multiple times across the width of 100 m.
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Number of pipes: The number of pipes needed is calculated by dividing the total width by the length of each pipe:
ext{Number of pipes} = rac{100 m}{100 m} = 1
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Total length of pipes:
The cost for the pipes can be calculated by:
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Cost of pipes per meter: R6,50
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Total cost:
Thus, the total length of pipes needed is 100 m, and the cost is R650.00.
Step 2
Calculate the total cost of the T-joints and elbows that you will need if there are 19 T-joints at R8,00 per T-joint and 4 elbows at R6,50 per elbow.
Answer
To find the total cost of the T-joints and elbows:
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Cost of T-joints:
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Cost of elbows:
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Total cost:
Thus, the total cost for T-joints and elbows will be R178.00.
Step 3
Explain the function of a one-way irrigation valve.
Answer
A one-way irrigation valve regulates the flow of water in a single direction, preventing backflow. This is crucial in irrigation systems to ensure that water is directed to the crops without the risk of contamination from the return flow.
Step 4
State FOUR advantages of sprinkler irrigation over flood irrigation.
Answer
- Efficient Water Use: Sprinkler systems minimize water wastage compared to flood irrigation.
- Uniform Distribution: Water is evenly distributed across the field, ensuring all plants receive adequate moisture.
- Reduced Soil Erosion: The gentle application of water reduces the risk of soil erosion.
- Adaptability: Sprinkler systems can be adjusted based on crop needs and weather conditions.
Step 5
Briefly describe the safety feature built into the centre pivot irrigation system to prevent the centre pivot from falling when one of the wheels gets stuck.
Answer
The safety feature in a centre pivot irrigation system includes an automatic shutoff mechanism that disconnects the electricity to the drive wheels when the system becomes misaligned. This prevents the other wheels from continuing to operate and potentially falling over.
Step 6
Give THREE important reasons why a farmer would prefer drip irrigation to an overhead irrigation system.
Answer
- Water Efficiency: Drip irrigation reduces water waste by applying water directly to the plant roots.
- Targeted Fertilization: Fertilizers can be applied through the system, improving nutrient uptake by plants.
- Reduced Weed Growth: By applying water directly to the plants, the moisture around weeds is minimized, thus reducing their growth.
Step 7
Step 8
Name THREE types of irrigation systems that can be used by farmers to water large fields.
Answer
- Flood irrigation: This method involves flooding the field with water.
- Hand move sprinkler systems: Sprinklers that are manually moved to different positions in the field.
- Centre Pivot irrigation: A rotating sprinkler system that irrigates the field in a circular motion.