Experiment: Comparing the water holding capacity of the soil

Materials: Measuring cylinders, funnels, cotton wool, water, dry soil samples, stop watch/clock

Method

1. Set up your apparatus as shown in the diagram
2. Add known volume of water
3. Measure the volume of water which drains through the soil after 20 minutes
4. Measure the volume of water that is held back by the water
5. Compare these volumes

Results

• Sand soils drain quickly and have a very small water holding capacity
• Clay soils retain most of the water
• Loam soils rank between sand and clay soils in their water retention capacity
• Dry soil samples are used so as to get accurate results as wet soils already contain water

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