2
Marks
1. With the help of chemical equations, outline the processes by
which the fertiliser known as nitrochalk is manufactured. 11
Name two other nitrogenous fertilisers, and for each calculate the
price per ton at which it would supply nitrogen at the same unit cost as
nitrochalk costing £18 10s. per ton. 4
Describe (i) the effects of nitrogenous fertilisers on the growth of
plants, and (ii) the symptoms of nitrogen deficiency. 5
2. Compare humus with clay in regard to (i) origin, (ii) physical
properties, and (iii) effects on soil texture. 10
Explain what is meant by base exchange in soils. 6
Explain how base exchange is related to (i) soil acidity, (ii) soil
texture. 4
3. Name three substances which are used for reducing soil acidity,
and explain their chemical relationships with one another. 5
State briefly the conditions under which a metallic element is
available to plants. Outline the experimental procedure you would
follow in order to determine whether a particular metallic element was
essential to plants. 7
Calculate the proportions by weight in which sulphate of ammonia,
superphosphate, and muriate of potash could be mixed in order to make
a compound fertiliser which would be suitable for a crop of turnips. 8
4. Draw a labelled diagram of a bucket milking machine installation,
and state the uses of each part. 8
Describe a teat cup. Explain fully how milk is extracted from one
“ quarter ” of a cow’s udder by use of a teat cup. 12
5. Describe a “ three speeds and reverse ” gear box. Explain the
action and uses of its parts. 20
6. Write explanatory notes about FIVE of the following : Ohm’s
Law ; transformers ; the cooling of a tractor engine ; storage of farm¬
yard manure ; seedbeds ; sugars. 4
each
7. Give an account of the uses of water in the bodies of animals. 10
Explain how the regional distribution of types of farming in Scotland
is related to climatic factors. 10
(C68S94)