Observation

(a) Most candidates were unable to state the aim of the experiment as many erroneously described it as a soil profile; thus mislabelling its parts .

(b)Candidates were however able to state the properties of sandy soil as well as describe a test for soil acidity using litmus paper..

The expected answers include:
1.   (a)(i) Aim of the experiment

- Separation of soil into its fractions/determination of soil texture by sedimentation                                                                                      

(ii)  Naming of the parts labelled I and II

        I – Clay in suspension/Clay

       II – Silt
                                                                          

(b)  Description of the experiment

- Place a glass jar on a surface

- Weigh about 70 – 100g of the soil

- Add the weighed soil into an equivalent quantity of water in a glass jar

- Add suitable dispersing agent e,g, NaOH, NaHCO3

- Shake the glass jar vigorously to disperse any soil clods

- Allow the glass jar to settle for an hour

- Observe the result

(c) Properties of sandy soils

- Low cation exchange capacity

- Diameter is between 0.02 mm – 2m2

- Well drained, loose and highly aerated

- Low plant nutrients

- Low buffering capacity

- Leaching of nutrients is high/supports leaching

- Easily gets hot and cold

- Low water holding capacity

- Particles are light and easy to till

- Gritty/rough/coarse in nature

- High percolation rate

- Low capillary action

- Cannot be moulded

(d)  Testing soil acidity using litmus paper

- Mix the soil very well

- Moisten with distilled water

- Dip red and blue litmus paper into moistened soil

- If blue litmus paper changes pink/red, the soil is acidic

- If red litmus paper changes blue, the soil is basic/alkaline

- If there is no colour change, the soil is neutral