Agriculture Paper 3, WASSCE (SC), 2021

Question 2

    (a) State six differences between specimens E and G.                                               [6 marks]
    (b)  (i) State the major plant nutrient element supplied by specimen E to the soil.  [1 mark]
    (ii) Name three other fertilizers that could supply the major plant nutrient element mentioned in 2(b)(i) to the soil.    [3 marks]
    (c) State five disadvantages of using specimen E in crop production.                      [5 marks]

    Candidates’ responses to Question 2 was below average.
    (a) Many candidates could not state the differences between urea fertilizer and poultry manure;
    (b) Many candidates listed varied nutrients as those that are supplied by urea to the soil instead of the major nutrient (Nitrogen);
    (c) Most candidates could only mention NPK as the fertilizer that could supply nitrogen to the soil;
    (d) Most candidates were unable to state the disadvantages of using urea in crop production.

Observation

The expected answers include:

 2.   (a)  Differences between specimens E (Urea fertilizer) and G (Poultry manure)      


Specimen E (Urea fertilizer)

Specimen G (Poultry manure)

-  Grey/brown colour/whitish colour

-  Dark brown/black colour

-  Inorganic fertilizer/chemically
synthesized

-  Organic fertilizer/of animal origin

-  Granular structure

-  Amorphous in nature

-  Contains only one element i.e.  
nitrogen

-  Contains many elements/variable
elements

-  Has known /fixed nutrient
composition

-  Has variable nutrient composition

-  Requires high skills to apply

-  Requires low skill to apply

-  Nutrient is readily available to
crops

-  Nutrient is not readily available to
crops

-  Microorganisms are not present

-  Contains high amount of
microorganisms

-  Does not improve soil structure

-  Improve soil structure

-  Odourless

-  Has an offensive odour

-  Non-bulky

-  It is bulky

-  Expensive

-  Relatively cheap

-  Can leach easily

-  Cannot leach easily

                                                            
 (b)   (i)   Major plant nutrient element supplied by specimen E (Urea fertilizer) to the soil         
-  Nitrogen                                                                                   

  (ii)  Other fertilizers that could supply the major plant nutrient in specimen E (Urea) to the soil
-    NPK fertilizer
-    Di-ammonium phosphate (DAP)/Ammonium phosphate
-    Calcium ammonium nitrate (CAN)
-    Sulphate of ammonia
-    Ammonia liquor     
-    Anhydrous ammonia
-    Ammonium nitrate
-    Sodium nitrate                                                                  

(c)   Disadvantages of using specimen E (Urea fertilizer) in crop production                    
-    Leaves acidic residues in the soil                             
-    High technical know-how is required to apply it
-    Expensive to procure
-    Easily leached/eroded from the soil
-    Could pollute agricultural land and water bodies
-     It is toxic to human health
-    Could destroy soil microbes
-    Could cause crop injury if not properly applied