Observation

Question 2 was fairly popular among candidates although many candidates were describing the features of soil profile and soil texture rather than their functions; thereby losing marks. Some candidates also failed to use conjunction in differentiating between forest and pasture.

The expected answers include:

(a)   Explanation of ways in which soil profile and soil texture are important in crop production
(i)    Soil profile
-     Depth of horizon A indicates adequacy of soil for cropping
-     Depth of horizon A is an indicator of soil fertility
-     Type of parent rock indicates mineral composition of soil
-     Used in soil classification/mapping
-     Type of crops to be grown in an area depends on the soil profile/root
penetration
-     The rate of percolation/prevention of soil erosion depends on the presence
of horizon A/ leaching
-     Determines depth of tillage         
(ii)  Soil texture
-     Determines the type of crops to be grown
-     Indicates the fertility status of the soil
-     Determines the rate of leaching of soil
-     Influences the rate of soil erosion
-     Influences the activities of soil microorganisms e.g. fine textured soils like
clay do not favour the growth of microbes
-     Influences soil aeration
-     Determines the water retention capacity of soils
        
(b)    (i)  Difference between a forest and a pasture
A forest is an area of land that is covered with trees and undergrowth of shrubs
While
a pasture is an area of land on which forage grasses and legumes grow

(ii) Pasture management practices in West Africa
-   Adequate stocking rate                          -  Pest control 
-   Controlled grazing/avoid overgrazing   -  Disease control
-   Weed control                                          -   Rotational grazing/paddocking
-   Fertilizer application                             -   Mixed grazing
-   Zero grazing/soilage                               -  Reseeding
-   Irrigation                                                -   Controlled burning
-   Cultivation of grass-legume mixture

                                                                                           
(c)        Characteristics of sedimentary rocks

• Occur in layers/strata
• They are soft
• Non-crystalline           

-     Contain fossils of plants and animals

• Coarse texture
• React with weak acid e.g. carbonic acid
• Easy to break
• Do not dissolve in water
• Vary in colour