i9 
Manures and Manuring 
fiuous water simply runs off the surface, or percolates very 
slowly through it, allowing the plant time to take up the 
nitrate. 
On light (sandy) soils where there is a sufficient or 
rather heavy rainfall it is better to use sulphate of ammonia. 
On sandy soils, however, where there is a deficiency of 
rain it is better to use nitrate of soda, or easily soluble 
nitrate manure. From what we have already learned 
about these two manures it will be seen that there must 
be a difference in the time of application. Nitrate of soda, 
when dissolved, is available to the plant as food, and must 
be applied when required by the vigorous-growing plants. 
On the other hand, sulphate of ammonia, which has to 
be dissolved and changed into a nitrate before it can be 
used by the plant as food, should be applied from three 
to six weeks — according to the season — before it is required 
in greatest quantity by the plants. About i cwt. per acre 
of these fertilizers is the amount necessary, or about i lb. 
to 40 sq. yd., and should be given three or four times 
during the vigorous-growing season. Care must be taken 
to prevent it getting on to the leaves of plants, or it will 
burn them. 
Many are familiar with the fine, green, healthy-looking 
appearance of crops after one application of nitrogenous 
manure. We therefore know that nitrates induce a strong, 
healthy growth, and this also gives us an idea of the kind 
of crops to which we should apply these manures. They 
should be crops which we wish to grow luxuriantly, such 
as Cabbages, Kales, Celery, Asparagus, &c. Other nitro- 
genous manures are nitrate of potash, which is too expensive 
and too dangerous for use except by experts; and guanos, 
