The diagram above illustrates an experimental setup to determine a soil property.
Study them carefully and answer the question that follows;
(a) Suggest a suitable title for the experiment. [1 mark]
(b) Outline the procedure for carrying out the experiment.[ 7 marks]
(c) identify the soil samples in diagrams 1, Il, and ll
(d) State two precautions to be taken when carrying out the experiment.[ 2 marks )
(e)(i) Which of the soil samples is prone to waterlogging?
(ii) Give one reason four your answer in (e)(i)
Explanation
(a) Title of the experiment;
- To compare porosity water holding/ retaining capacity of different soil types
(b) Procedure for carrying out the experiment
- Obtain samples of sandy, clayey and loamy so-Dry them under the sun.
- Grind loamy and clayey soils
- Plug the necks of three funnels with cotton wool
- Put equal volumes of sandy, clayey and loamy soils separately into three funnels plugged with cotton wool.
- Tap the funnels carefully on the bench until all air spaces are filled with soil
- Stand each funnel in the open end of a measuring cylinder.
- Pour 50cm of water into the funnel containing each soil sample.
- Allow the setup to settle for at least 1 hour.
- Measure the amount of water that dripped through each soil sample.
- By subtracting the amount of water that dripped through each soil sample, obtain the amount of water retained in each soil sample.
(c) ldentification of soil samples
- Set up I - Loam/Loamy soil
- Set up Il - Sand/Sandy soil
- Set up Ill- Clay/Clayey soil
(d) Precautions to be taken when carrying out the experiment
- Soil samples should be dried under the sun
- Loam and clay should be ground before use
- The funnels should be properly plugged with tton wool to prevent soil samples from dripping into the measuring cylinders,
- The funnels should be properly tapped to close ces that could distort the experiment.
- Cylinders should be placed on flat and level surface.
- Water should be poured into the cylinder at the all same time.
(e)(i) Soil sample in set up ll (clay) is prone to waterlogging; Soil sample in set up llI (clay) is prone to waterlogging
(ii) Reason;
- Presence of small pore spaces which do not allow water to drain easily/small fine particles