1 Fes., 1902.] QUEENSLAND AGRICULTURAL JOURNAL. 73 
Agriculture. 
FIRST STEPS IN AGRICULTURE. 
lirn Lesson. re 
SECOND STAGE. 
By A.J.B. 
In former lessons you have learned much about the soil, about the 
constitution of plants, about the manner in which they obtain their food, and in a 
general way you have been introduced to the methods of improving the soil 
and increasing the yield by the application of manure, by draining, irrigation, 
&e. We may now go a step higher, still dealing with the same subjects. 
Taking the soil first, we will make a few experiments to prove what I have 
already told you about the constituents—that is, the various ingredients that go 
to make up a soil. In fact, what follows is a simple lesson on “ Analysis.” 
Let us take a spadeful of soil and weigh it. After weighing, we will 
expose it to the sun and wind. What will happen? You know, if you take a 
sponge or a pocket handkerchief and saturate either with water, that it will 
increase in weight. Now, squeeze out the sponge and the handkerchief and set 
them in the sun and wind to dry; then weigh them. You, of course, find that 
they weigh far less than they did when full of water. That is because they 
have parted with all their moisture by evaporation. The same thing happens 
with the spadeful of soil. When we dug it up, it held a certain amount of 
moisture. By exposing it to the sun and air, it parted with much of this 
moisture, but not with all. You can prove this by putting the soil, after it has 
been in the sun, into a frying-pan, say in some warm corner, and still more 
moisture will be given off. Now put the frying-pan over a hot fire; you will 
notice that sparks appear amongst the soil—in fact, it begins to burn. But 
I must here tell you that all soils do not show the same results by these 
heating experiments. You know that rich soils consist of a large amount 
of organic matter, that clay soils contain scarcely any, and pure sand 
contains none except what may be mechanically mixed with it. A sandy 
loam will also contain a certain amount of organic matter. These 
yarious soils also differ in the amount of moisture they contain. Well, 
when you see your soil in the pan emitting sparks, you know that the 
organic matter (which’I told you was called “ humus”) is what is burning, and 
this passes off in the shape of steam and carbon, as you already know. But 
there are other things in the soil which can be dissolved in water. The organic 
‘matter cannot be dissolved. If you carefully weigh a portion of soil, and then 
stir it up in water and allow the mixture to settle until the water is perfectly 
clear and the soil lies at the bottom of the vessel you mixed it in, you will find 
when you have poured off the water that it contains something it did not contain 
before. This you may prove in several ways. One way is by again weighing 
the soil, which you will find to be lighter than before. But the easiest way is 
to expose the water to heat until it has all evaporated, and then you will find 
that there is something left behind, something of a greyish white colour. This 
is one or, perhaps, a mixture of several salts, such as salt, magnesia, &c., and 
you can be quite satisfied that these were not contained in the water you mixed 
the soil in, if you evaporate some of the same water which has not been added 
to the soil. You will find that it leaves nothing behind it. So yousee we have 
now taken the water, the organic matter, and the salts out of the soil. Now, 
it is very important that you should remember all this, because, as you are 
aware, the plants feed on the organic and soluble parts of the soil. By soluble 
parts I mean those that are soluble in water, as you saw in the case of the sugar, 
6 
