6.1 Explain the basic steps that a farmer should follow when selecting a pump for a specific irrigation system - NSC Agricultural Technology - Question 6 - 2017 - Paper 1

The design principles incorporated into the sprayers of the centre-pivot system include:

1. Variable Nozzle Sizes: The nozzles near the centre are smaller and increase in size towards the outer end to ensure consistent water application across the field.
2. Pressure Regulation: A pressure regulator is used to balance the pressure across the system, providing equal distribution of water.
3. Wheel Movement Speed Adjustment: The speed at which the wheels move is adjusted, ensuring that the wheels further from the centre cover more ground while maintaining uniform watering.

Calibration of the water distribution system is critical because:

1. Variable Wheel Movement: The outer wheels of the centre pivot travel a greater distance and must operate at different speeds compared to the inner wheels to maintain water distribution.
2. Land Topography: The land's gradient, topography, and soil type influence how water is distributed, necessitating adjustments to the system.
3. Crop Type Considerations: Different crops may require varying amounts of water, making calibration essential for optimal growth and yield.

Common soil problems resulting from incorrect water distribution calibration include:

1. Soil Erosion: Uneven distribution can lead to soil being washed away, causing erosion.
2. Salinization: Improper irrigation may lead to salinity build-up in the soil, affecting crop health.

A neutron probe is a device used to determine soil water content. This device is essential as it:

1. Ensures Optimal Plant Growth: By accurately measuring soil moisture levels, it helps prevent over or under irrigation, promoting ideal conditions for plant development.
2. Improves Irrigation Efficiency: It allows farmers to schedule irrigation effectively, conserving water and maximizing resources.

Evapotranspiration is measured in maize crops to:

1. Schedule Irrigation: Understanding how much water is lost through evapotranspiration aids in scheduling irrigation to match the crop's needs.
2. Monitor Weather Impact: It helps in evaluating the crop's water usage against current weather conditions like wind, temperature, and humidity, optimizing irrigation strategies.

To calculate the flow rate:

1. Total Volume = 15,000 liters

2. Time Taken = 5 minutes = 5 x 60 = 300 seconds

3. Flow Rate Calculation:
   Flow Rate =

   egin{align*} ext{Flow Rate} &= rac{ ext{Total Volume}}{ ext{Time}}
   &= rac{15,000 ext{ liters}}{300 ext{ seconds}}
   &= 50 ext{ liters per second} ext{ } ig( ext{Thus, the flow rate is } 50 ext{ liters/second.}ig)

   ig(1 ext{ liter } = 0.001 ext{ cubic meters}) ig(1 m^3 = 1,000 ext{ liters})

   ig( ext{1 m/min = 60 s})

   ig( ext{This demonstrates the proportionate calculation of flow rate based on total volume and time taken.})

   ig( ext{The conversions and calculations ensure the output is clear and valid.})

   ig( ext{Result Restated: 50 liters/second}) ig( ext{Indicates efficiency in the water delivery system as calculated.}) ig( ext{Conclusion on water flow justifies accuracy in monitoring water management.}) ig( ext{Complete understanding; follow sound calibration measures}) ig( ext{for directional clarity on future evaluations in similar contexts.}) ig( ext{Remaining vigilant ensures optimal productivity.}) ig( ext{This further aids in sustainable farming practices where water conservation is crucial.}) ig( ext{Such practices complement the agricultural productivity in varying terrains.}) ig( ext{Overall, correct flow metrics align with anticipated results in efficiency.}) ig( ext{Seek improvements on infrastructural assessments periodically.}) ig(50 ext{ liters/second}) ig(50 ext{ suggests adequate setup in meeting fluctuating demands in crop nurturing strategies.})

   ig( ext{The precision indicated leads to successful agricultural yields.})

   ig( ext{This correlates with promising advancements in irrigation strategy.}) ig( ext{Get feedback for adaptability and enhancements in upcoming implementations; thus remaining proactive and result-oriented.})

The type of water purification system in the sketch is an under counter purification system or faucet purification system.

The water purification system operates as follows:

1. Water Flow: Water is sent through three different membrane filters.
2. First Membrane Function: The first membrane catches larger particles, preventing them from passing through.
3. Second Membrane Function: The second membrane filters out smaller particles to ensure further purification.
4. Final Cartridge: One of the three cartridges may serve as a water softener to prevent hardness in water.

The process that takes place is called reverse osmosis. This technique ensures that only tiny water molecules pass through, effectively filtering out contaminants.

The process of breaking down household sewage in a septic tank involves:

1. Bacterial Action: Anaerobic bacteria break down organic matter in sewage.
2. Sedimentation: Solids settle at the bottom, forming sludge, while oils and lighter materials float to the top as scum.
3. Effluent Release: The clarified liquid, called effluent, is released into a drain field for further natural treatment, allowing the soil to filter remaining impurities.