Observation

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


2. 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. 1. Aim of the experiment
   
   

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

   
   
   2. Naming of the parts labelled I and II
   
   

   I Clay in suspension/Clay

   
   

   II Silt

   
   
2. 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



3. Properties of sandy soils



-Low cation exchange capacity




-Gritty/rough/coarse in nature




-Diameter is between 0.02mm – 2m²




-High percolation rate




-Well drained, loose and highly aerated




-Low capillary action




-Low plant nutrients




-Cannot be moulded




- 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



4. 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