Observation

This question was surprisingly challenging to the candidates. The candidates misinterpreted the main effects of the listed factors on pasture development instead of pasture distribution. Candidates were therefore discussing how the factors affect productivity. In question 2 (b), students could not state the physical factors affecting pasture establishment.
 
 The expected answers include:

2.(a)   Ways in which the following factors affect the distribution of natural pastures

 (i)    Rainfall

• Intensity and distribution determine the vegetative cover of an area
• Drought tolerant grasses are found mostly in drier parts of the country with low rainfall
• Those requiring lots of water for growth are found in the wetter parts of the country
• Natural pastures are hardly found in the very high rainfall forest belt of the country
• Natural pastures have different water requirement for their growth

(ii) Sunlight

• Helps in breaking seed dormancy hence the tendency to have more grasses germinating in areas with high sunlight.
• In forest areas, grass species tend to grow tall in an attempt to seek for sunlight, such grasses have tall slender stems which may not reach maturity, hence fewer grasses.
• Controls flowering in some pasture crops, hence areas with high sunlight intensity tend to have more pasture crops which are propagated by seeds.
• Drought tolerant species of forage crops thrive in areas with prolonged sunlight without rainfall.                                         

(iii) Human Activities

• Regular and persistent bush burning will reduce natural pastures
• Land clearing for farming reduces natural pastures
• Removal of trees and shrubs for other uses will enhance pasture growth
• Use of land for other purposes such as housing will limit distribution pastures
• Over-grazing leads to depletion of natural pastures                                                                                                                                                     

(iv) Wind

• Influences the rate of transpiration, hence, reduces survival rate of pasture crops
• Causes soil erosion in dry/arid areas, thus disturbing the growth of pasture species
• Important in rainfall distribution hence influences availability of pasture crops
• Influences the rate of evaporation in the soil and hence germination and growth of pastures
• Influences dispersal of seeds of pasture crops

     
(b)Physical soil factors that affect the establishment of forage crops

• Soil texture
• Soil strength/soil consistency
• Soil structure
• Soil colour
• Water holding capacity/ soil porosity/soil water
• Humus/Organic matter     
• Soil temperature