522 QUEENSLAND AGRICULTURAL JOURNAL, {1 Dec., 1901. 
you would soon lose all the potash in it, and then, unless you supplied more, you 
could no longer grow cabbages; but wheat, which is not so greedy for potash, 
will thrive after cabbages. 
Just to illustrate this to you, let us suppose that in your garden there 
are four kinds of fruit, and four of you are allowed to eat as much as you like 
every day. Say that there are oranges, guavas, passion fruit, and strawberries. 
If every one of you liked strawberries better than anything else, the straw- 
berry bed would be cleared before the other fruit. You do not care for the 
other fruit much, so you leave the garden. Now, three other boys are sent in. 
They like all fruit, but one likes guavas best, another oranges, the third prefers 
passion fruit, but all take some of each. As neither of the varieties of fruit 
is consumed exactly in the same proportion, it takes a much longer time to 
dispose of it than in the case of the strawberries, so there is still some left 
for other boys. 
So it is with the crops I have told you of—one plant will use up much 
more of a particular ingredient than another, and the knowledge that this is 
so enables the farmer to raise good crops of several kinds by merely taking 
care to change the order of sowing or planting. 
Now, I will give you an example by telling you what was done by some of 
the old wheat-growers in Victoria. In that State flax is grown. Flax produces 
linseed, and linseed is very valuable in the dairying business. Now, linseed 
grown in alternation with wheat gives good results in this way: A crop of 
linseed takes up a different set of soil constituents (or plant food) for its 
nourishment to that which cereals (wheat, maize, oats, barley, &c.) require. 
and it has been proved that it exercises a good fertilising influence, and this 
effect is well known to growers in South Australia, especially in one par of 
the State which was famous for flax-growing. Consequently the wheat farmers 
grew a crop of linseed followed by wheat. When this was known in Victoria, 
a farmer of that State tried a crop of flax on a piece of land which had become 
“orain-sick” from constant cropping with wheat, and the result was that he 
got an excellent crop of linseed followed by a big wheat yield. This is a very 
good instance of the good effects of rotation. 
Now, there are certain rules to be observed in rotation, and several writers 
have stated them as follows :— 
Such plants as tend to particularly exhaust the soil, like grain crops, 
should only be sown when the land is in “ good heart’’—i.e., perfectly fertile 
like the virgin soils I have mentioned. They ought not to succeed each other, 
but should be followed by plants which are less exhausting. 
It is a good thing to alternate plants that have tap roots with those which 
have spreading roots. 
No two crops which favour the growth of weeds should follow each other. 
And the same with insects and fungi. . 
Crops should be changed frequently to hinder the increase of these pests. 
You have probably heard farmers complain of the wire-worm and cut-worm 
attacking the wheat and barley. 
Now, to get rid of that ruinous pest, a crop of turnips or beans should be 
sown, and then the whole tribe of grain insects may perish or disappear for 
want of proper food. The sugar beet is so liable to disease that in Germany 
they say that sugar beets should not be grown on any field oftener than once 
in every six or eight years. 
Now, I am not going to explain to you the various rotations employed in 
different parts of the world. We shall come to them by and by, but the 
following Four-Coursz or Norrork Rorarron will just give you an insight 
into the method. 
The Norfolk rotation is a very old one, probably 100 years old. It is 
called “rour-coursE” because it consists of a series of four crops, each of 
which comes round on the same land in proper order every four years. It is 
adopted mainly on light soils, 
