The diagram below illustrates an experimental set-up on soil. Study it and answer the questions...

Explanation

(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