This question was not popular with the candidates. In 3(a), majority of the candidates could not state the
meaning of soil consistency. In addition to this, in 3(b) (i and ii), most of the candidates were unable to
explain how soil properties influence crop growth (i.e. soil texture and soil pH).
However, in 3(c) (i) and (ii), many candidates were able to list methods by which soil fertility could be
maintained and ways in which the methods contribute to the maintenance of soil fertility.
The expected answers include:
Meaning of soil consistency
Soil consistency is the resistance of soil to pressure and other physical manipulation.
Explanation on how soil properties inflnence crop growth
Soil texture
Determines water liolding capacity of soils;
Influences air movement in the soil;
Affects root penetration;
Affects soil workability;
Has direct effect on soil drainage/infiltration;
Affects the retention of plant nutrients.
Soil pH
Generally, extreme pH values affect the activities of soil micro-organisms.
Affects the availability of plant nutrients\affects the solubility of certain elements which
may be toxic to crops at high concentration.
Crops perform poorly outside their required pH range.
Controls cation- exchange- capacity (C.E.C.) of the soil.