80 QUEENSLAND AGRICULTURAL JOURNAL. {1 Fxs., 1902. 
advantage to use artificial manures. I use the term artificial, although itis not 
strictly correct, for, as I explained to you before, there are some valuable 
manures which are found in a natural state, and are used in that natural state. 
These are Guano, Nrrrate oF Sopa, Karnit, Sant, Gyrsum, &c. Other 
manures are manufactured from various substances. But it is the custom to 
merely distinguish the two classes of fertilisers as FARMYARD manure and 
ARTIFICIAL manures. We will, therefore, consider all manures which do not 
consist of dung as artificial. 
Now, before going further, we will sum up in a short way the contents of 
this lesson, so that you may the more easily answer the questions I shall 
shortly give you. 
You were first shown how the farmer disposes of the manure from his 
outhouses and yards when he has no time to cart it on to the fields. Next I 
explained to you how proper dung pits should be made, and why it is necessary 
to make tanks to receive the drainage from the pits. It was then shown how 
the action of oxgen on the manure heap caused fermentation to set up, and 
how this fermentation could be controlled so that it would proceed rapidly or 
slowly. The constituents lost in the process of fermentation and by evaporation. 
and the constituents contained in the manure, you also heard about. Finally, 
I told you that artificial manures are for several reasons preferred by farmers 
to farmyard manure alone. 
We will now discuss the natural and artificial manures separately, for you 
will find there is much to learn about them. Now, what are the constituents 
‘of the soil which are the first to become exhausted by successive cropping ? 
They are Porasn, NirroGEN, Puospnoric Actp, and Line, and it is to supply 
the loss of these constituents, as well as to bring into activity the dormant 
sources of fertility which are still in the soil, that artificial manures are applied. 
But you must remember that, whilst farmyard manure improves the condition of 
the soil, these artificial manures do not do so. They supply the needful plant 
food, and merely assist to keep the soil in proper condition, but do not make 
the soil fertile. The great advantage of their use is that they furnish a 
quantity of plant food in very smail bulk, and thus save great expense in labour 
and carriage. Some of them contain only one fertilising ingredient, and these, 
therefore, are distinguished as NITROGENOUS, of which class Peruvian Guano is 
an example: Puospuarrc, as Superphosphates, Phosphate of Lime, Basic Slag, 
&e.; and Porasn Manvres, as exemplified by Kainit and Muriate and Sulphate 
of Potash. 
All these haye their own special uses, and some, when mixed in certain 
proportions, are termed PERFECT OR COMPLETE FERTILISERS. 
Some act very readily, such as Guano and Nitrate of Soda. They are very 
active stimulants, and have to be used with great care, and generally in 
conjunction with other manures. 
Amongst the nitrogenous manures we will discuss Peruvian Guano. 
The value of this natural manure consists in the Ammonia, Phosphoric 
Acid, and Potash it contains. It is supposed to be the excrement of birds 
accumulated during a long series of years in a climate where there is no rain to 
wash away the soluble salts it contains. I may tell you that I have visited the 
guano islands of Peru, named the Chincha Islands. When I was there, three 
large islands were covered with solid guano to a depth of from 50 to 250 feet. 
The labourers have often to use powder to blast it out. It contains immense 
uantities of Carbonate of Ammonia, and the sailors pick out large lumps of 
this and take it home with them. There is very little left there now, but guano 
is obtained from the main land of Peru, and on some islands on the coasts of 
New Zealand, and parts of Australia. The Chincha Island guano used to be 
yery rich in ammonia—as much as 18 per cent. ; but of late years it barely has 
contained half as much, sometimes only 4 per cent. It should always be used 
mixed with some soil, or injury would oat to seeds and plants if it were used 
pure. 
