Observation

This question was fairly attempted by the candidates.  In 2(a), most of the candidates could not state the advantages and disadvantages of using biogas as a source of farm power though majority of them were able to mention simple farm tools as required in 2 (b).  In 2(c-d), majority of the candidates could neither list the common storage and processing structures found on farmsteads in West Africa nor explain what is meant by denitrification.  However, majority of the candidates were able to describe soil components such as mineral matter and organic matter as required in 2(e).

The expected answers include:

2 (a)  Advantages and disadvantages of biogas as asource of farm power
         Advantages
-     It reduces environmental pollution
-     It is easily controlled/easy to operate
-     Animal dung is cheap
-     Provides economic value to animal wastes/provides proper use of animal wastes
-     It can be used for different farm operations like heating the brooder house, drying etc

 Disadvantages

• It requires high technical know-how
• It is not a common source of farm power
• Its use is limited to areas where there is abundance of animals
• it is expensive to set up and maintain

(c) Common storage structures and processing structures found on farmstead in West Africa
                Storage structures

- Barns
- Bins
- Cribs
- Silos
- Drums
- Cages
- Bags
- Baskets
- Rhumbu
- Farm store/warehouse
- Underground pits
- Platforms
- Cold room/cold store

            Processing structures

- Abattoir
- Milk pasteurizing shed
- Fish or meat smoking shed
- Rice mill
- Cassava mill
- Oil mill(for oil crops)
- Curing house for tobacco
- Shelling barn

 (d)  Explanation of denitrification
This is the process whereby soil nitrates are converted to nitrogen gas, nitric oxide or nitrous oxide through the activities of denitrifying bacteria