waecE-LEARNING
Agricultural Science Paper 3, Nov/Dec 2012  
Questions: 1 2 3 4   Main
General Comments
Weakness/Remedies
Strength













































Question 1

(Question 1

  1. (i)   Name the illustrated irrigation system.                                                           [1 mark]

(ii)        Describe how the system is operated                                                              [3 marks]
(iii)       State two other surface irrigation methods for large farming.                        [2 marks]
(iv)       State two advantages and two disadvantages of the illustrated
irrigation system.                                                                                             [4 marks]

  1. (i)   Name the types of soil structure illustrated by P and Q.                                [2 marks]

     (ii)  Mention the soil type in which each of the structures is found.                     [2 marks]
     (iii) Which of the two structures favours the cultivation of swampy rice?           [1 mark ]

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OBSERVATION

This question was fairly attempted by the candidates. Most of the candidates could not name the illustrated irrigation system as required in1(a)(i). In 1(a)(ii), majority of the candidates could not describe how the system is operated.  However, many of the candidates were able to state two other surface irrigation methods for large scale farming as required in 1(a)(iii) but most of them could not state two advantages and two disadvantages of the illustrated irrigation system as required in 1(a)(iv).  In 1(b)(1-ii), majority of the candidates could neither name the types of soil structure illustrated by P and Q nor mention the soil type in which each of the structures is found.  More so, most of the candidates were unable to state which of the two structures favours the cultivation of swampy rice as required in 1(b)(iii).

The expected answers include:
1(a)(i)Name of irrigation system

  • Furrow irrigation

    (ii)    Description of how the system is operated

  • furrows are constructed, with bunds on all sides to prevent spillage
  • sluice gates are fixed at the point of entrance to each bed
  • water is pumped/poured into main channel
  • as water in sufficient quantities flow in from main channel to secondary channels through the sluice gates
  • sluice gate into the next bed is opened
  • water flows into the bed to flood/irrigate it
  • the cycle continues           

   (iv)Advantages and disadvantages of illustrated irrigation system
      Advantages

  • Cheap to start
  • Easy to carryout
  • Low cost of maintenance
  • Requires low technical know-how (knowledge)

      Disadvantages

  • Requires large quantities of water
  • Impedes machines movement
  • Laborious
  • Breeding ground for vectors and pathogens
  • Wasteful of land
  • Poor distribution of water on sandy soil

(b)(i)Name of types of soil structure illustrated by P and Q soil structure
      Soil Structure
      P   -     Crumby
      Q  -     Platy/Platelike

 

(ii) Soil type in which each of the structure is found
      Soil structure

  • P   (Crumby) is found in loamy soil
  • Q  (Platy/Platelike) is found in clayey soil

                                                                 
  (iii)Soil structure that favours the cultivation of swampy rice
Q  (Platy/Platelike)                                                      

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