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| Agriculture |
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| Copper Sulfate's Role in Agriculture |
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 Copper
sulphate has many agricultural uses but the following are the more
important ones:
• Preparation of Bordeaux and Burgundy mixtures on the farm
• Control of fungus diseaseso Correction of copper deficiency
in soils
• Correction of copper deficiency in animals
• Stimulation of growth for fattening pigs and broiler chickens
• A molluscicide for the destruction of slugs and snails, particularly
the snail host of the liver fluke
Preparation of Bordeaux and Burgundy mixtures on the farm
Because of their importance to farmers, instructions concerning the
dissolving of copper sulphate and the preparation of both Bordeaux
and Burgundy mixtures have been included in the text.
Dissolving copper sulphate Iron or galvanised vessels must not be
used for the preparation of copper sulphate solutions. Plastic vessels,
now freely available, are light and very convenient. To make a strong
solution, hang a jute sack of copper sulphate so that the bottom of
it dips a few inches only in the water. The copper sulphate will dissolve
overnight. Copper sulphate dissolves in cold water to the extent of
about 3 kg per 10 litres. If more than this is placed in the sack
described above, then a saturated solution will be obtained and it
may be used without serious error on the basis that it contains 3
kg copper sulphate per 10 litres.
Preparation of Bordeaux mixture
Bordeaux mixture is prepared in various strengths from copper sulphate,
hydrated lime (calcium hydroxide) and water. The conventional method
of describing its composition is to give the weight of copper sulphate,
the weight of hydrated lime and the volume of water in that order.
The percentage of the weight of copper sulphate to the weight of water
employed determines the concentration of the Bordeaux mixture.
Thus a 1% Bordeaux mixture, which is the normal, would have the formula
1 :1:100, the first 1 representing 1 kg copper sulphate, the second
representing 1 kg hydrated lime, and the 100 representing 100 litres
(100 kg) water. As copper sulphate contains 25% copper metal, the
copper content of a 1% Bordeaux mixture would be 0-25 % copper. The
quantity of lime used can be reduced considerably. Actually 1 kg copper
sulphate requires only 0.225 kg of chemically pure hydrated lime to
precipitate all the copper. Good proprietary brands of hydrated lime
are now freely available but, as even these deteriorate on storage,
it is safest not to exceed a ratio of 2:1. i.e. a 1:0.5:100 mixture.
In preparing Bordeaux mixture, the copper sulphate is dissolved in
half the required amount of water in a wooden or plastic vessel. The
hydrated lime is mixed with the balance of the water in another vessel.
The two "solutions" are then poured together through a strainer into
a third vessel or spray tank.
Preparation of a 1% Burgundy mixture
Dissolve separately 1 kg copper sulphate in 50 litres water and 125
kg washing soda (or 0.475 kg soda ash) in 50 litres water and slowly
add the soda solution to the copper sulphate solution with stirring.
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