Marks
4. Describe in detail an experiment to determine which elements are essential for
healthy plant growth. Name six such elements and indicate the symptoms by
which a deficiency of each can be detected in growing plants. (17)
Name the essential elements which are commonly applied as fertilisers and
explain why only a few essential elements are applied in this way. (3)
5. Explain, with examples, how you would determine (a) which of two fertilisers,
both containing the same essential element, provides the better value and (b)
which contains the higher percentage weight of the essential element in the
pure substance. (5)
Give an account, with chemical equations, of one method by which ammonium
sulphate is manufactured. (10)
Discuss briefly the points which a farmer should consider before he decides
which fertilisers to apply to a particular crop.. (5)
6. Explain in detail (a) what is meant by hydrogen-ion concentration, (b) the
relationship between the hydrogen-ion concentration and the pH of a solution,
(c) the effect on the soil pH of adding lime to the soil, and (d) the practical
value of knowing the pH of each field of a farm. (20)
7. Write explanatory notes about FOUR of the following:—
lubrication and lubricants; the cooling of tractor engines; the principle of
the hydraulic lift; Ohm’s Law; safety precautions with electricity; crumb
structure in soils. (5) (each)
(C41541)
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