384: QUEENSLAND AGRICULTURAL JOURNAL. [1 Ocr., 1899. 
matter that is mixed with the bones proper; and fowl manure, stable manure, the 
droppings of all animals, especially sheep, nightsoil refuse, skin and hair, an 
several other ingredients contain a small proportion of nitrogen, and are 
valuable as manures. But, as [mentioned at first, there are three main sources of 
supply—sulphate of ammonia, dried blood, and nipho. Sulphate of ammonia 1s 
obtained asa waste product from the gasworks, and, though costing £10 10s. per 
ton, itis the cheapest form in which nitrogen can be supplied to the land, Sulphate 
of ammonia acts very rapidly on any trees or plants to which it is applied, 
producing a vigorous growth, and imparting a dark-green, healthy colour to the 
foliage. It should never be applied except when the tree is in actixe growth, as; 
on account of its solubility, if applied at any other time, it is apt to be washed out 
of the soil, especially if the soil is of a porous nature, when it is always advisable 
to apply it to the trees at two or three dressings rather than all at once. 
Sulphate of ammonia is an exceedingly stimulating manure, and it has the 
power of forcing the soil—that is to say, it produces a very vigorous leaf 
growth, which, in its turn, makes a very greatly increased call on the roots, 
which again take from the soil an increased amount of plant food, so that it 18 
not advisable to use sulphate of ammonia unless you feed your soil with the 
necessary potash and phosphoric acid required by the tree. Used alone, it will 
so impoverish your soil that finally-it will produce nothing—a result that I have 
noted when in Scotland, where, through the continual manuring of the soil with 
nitrate of soda (the action of which is similar to sulphate of ammonia), and by 
its use forcing big crops which were sold off the land, I have seen soils com- 
_ pletely played out that took years of eareful cropping and manuring 10 
bring into fair heart. Used judiciously, sulphate of ammonia is one of the 
best manures that can be applied to an orchard, especially if the trees are 
a bit sickly and off, when, if aR? roots are sound, and the trees are not showing 
badly through want of drainage, they may be brought round into vigorous 
health, provided, when they are started, that other manures are available from 
which the trees may obtain the necessary food wherewith to maintain their 
increased growth, ; 
Tn dried blood and nipho the nitrogen is not in as readily available a form 
as in the sulphate of ammonia, as it is present in the form of albuminous matter, 
which has to be converted first into ammonia, and then into nitrates, before it 
can be used by plants. Its action is thus much more lasting than that of 
sulphate of ammonia, as it continues to supply nitrogen to the plant for 4 
considerable time. For this reason nitrogen from organic sources is considered 
to be of aslightly higher manurial value than that obtained from inorgani¢ 
sources. Thus sulphate of ammonia should be used in conjunction with the 
soluble phosphates and potash to start the growth, and dried blood or nipho 
used in conjunction with bonemeal or other slowly available phosphate to 
supply the plant food when the more readily available and soluble foods have 
hecomeexhausted. Before I conclude speaking about nitrogenous manures there 
is one point I should like to call attention to, and that is that many substances, 
such as refuse skin, hair, and leather, though containing often a considerable 
amount of nitrogen, as shown by analysis, are yet of very little value for 
manure, and this is due to the fact that the nitrogen is in an unavailable 
form, and only becomes available very slowly in the soil. 
There is one other very cheap and efficient way of applying nitrogen to the 
soil, and it is the one that is given least attention to—viz., green manuring- 
As I have already mentioned, leguminous plants have the power of assimilating 
_ nitrogen from the air and of storing it up, so that if these plants be sown in 
the orchard, and ploughed in when they contain the most manurial mattter, 
which is just before the pod ripens, the soil will be enriched by the amount of 
the nitrogen that has been obtained by the plants from the air. The question 
of green manuring is, however, one of such importance that it will be dealt with 
fully later on. ~ a 
Probably no plant food is so generally deficient in Queensland soils as 
nitrogen, especially in soils that have been under crop for a number of years. — ' 
