1 Jan., 1902. ] QUEENSLAND AGRICULTURAL JOURNAL, 3 
Agriculture. 
FIRST STEPS IN AGRICULTURE. 
8rH Lusson. 
SECOND STAGE. 
By A.J.B. 
We have briefly considered Fallowing, Rotation, and Green-manuring as 
means of increasing the fertility of the soil. In this lesson we will take an 
elementary view of sUBSorLING and DRAINING, which were touched upon in the 
8rd and 7th Lessons of the First Book. 
When we speak of a subsoil, we mean that portion of the soil lying at from 
6 to 12 inches from the surface. (Lesson 3, I.) In many cases, if this subsoil 
is brought to the surface, it is found to be wanting in fertility for a considerable 
time, until it has been exposed to the influences of the air, rain, sun, and frost. 
You often notice a difference in the colour of the surface and subsoils, and the 
latter is often heavier if it contains much clay, or lighter if it is composed of 
gravel or limestone. 
The subsoil may, in many instances, be as rich as the surface soil, and 
scarcely be distinguishable from it in colour or even in texture. ‘lake as an 
instance some of the wonderfully fertile scrub soils of Queensland or the black 
volcanic soils. There is practically, in such cases, no subsoil until a very great 
depth of rich surface soil has been passed through, although you must 
remember that we only call the soil to a depth of from 8 to 12 inches a true 
surface soil. 
A. gravelly subsoil should never be brought to the surface; indeed, it is 
dangerous to bring up a clay subsoil, as it may contain poisonous elements 
injurious to any crop sown or planted on it. 
The real object of subsoiling is to loosen the subsoil, to break it up without 
bringing it to the surface, and thus afford more room for the rootlets to go 
down in search of plant food and water. By constant ploughing, what is called 
a “prougH PAN” forms on the surface of the subsoil, owing to the friction of 
the bottom part of the plough in sliding over it, and also to the treading of 
~ men and horses. Now, this hard layer prevents the passage of water, and is 
too hard for the rootlets to penetrate it. The water lying on it becomes 
stagnant, and the crop, as you have already been told, syffers from the cold, 
wet soil. The subsoil plough breaks up this hard layer, and not only isa 
passage thus made for water, but more room is given to the roots to strike 
downwards, and hence more plant food is made available. 
Subsoil ploughing is very hard work for horses, from four to six horses 
being required for the work. 
We will now consider the very important matter of Drarnace. 
Now, first of all, what does drainage mean? (Lesson 6,1.) It means, 
generally, the carrying off of superabundant or stagnant water from the land, 
and it is done by means of ditches and trenches. The objects to be attained by 
drainage are fourfold. First, as I have just told you, to get rid of the water by 
running it off through the soil. Secondly. to give more plant food by lowering 
the water-level and thus deepening the soil. ‘Third, and this will seem strange 
to you, to retain the moisture in the soil. Fourth, to aerate the soil—z.e., to 
allow the air to circulate freely underneath the surface. You probably wonder 
why I tell you that you must drain to get rid of the water, and yet drain to 
keep it in the soil. I. will explain this later on. 
We will consider each of these objects. We want to get rid of the super- 
abundant water. Why? Because stagnant water keeps the soil cold and sour, 
znd thus spoils it for crop-producing. This, you will remember, was explained 
