1 Dec., 1901.] QUEENSLAND AGRICULTURAL JOURNAL. 521 
rich timbered land has been cleared, or when the black and red voleanic soils 
have been ploughed up, farmers plant the same crops for years on them, 
without diminishing the yield. Such vrrern soils, as they are called, need no 
care on the part of the farmer beyond good tillage, and keeping the weeds 
down, with here and there a little drainage perhaps. Weeds are the greatest 
trouble, especially on newly cleared scrub lands, where all work has to be done 
with the hand hoe for the first three years owing to the numerous stumps. 
But, as I have already told you, there must come a time when the wonder- 
ful fertility of the once virgin soils becomes less. You must now know the 
reason for this. Make it a point of always asking “Why?” Find out the 
reason for all that happens, and all that requires to be done, and you will end 
by being an intelligent farmer. Then you begin to find out that it will not do 
to continue growing the same crop year after year. And this it is which has 
given rise to Rorarton or Crors. The word means the order in which certain 
crops follow each other. You know that some plants require more of one kind 
of food than others. If, therefore, you continue growing the same crop in 
succession, it will end by exhausting that particular ingredient. But, if you 
change the crop, such exhaustion of any particular plant food does not readily 
occur. For instance, wheat, maize, barley, and oats require a great deal of 
silica, but not much lime or potash; whilst rice, root crops, and leguminous 
plants require a great deal of lime and potash and very little silica. So you 
can quite understand that a very good crop of roots may be got where you 
would have had a poor crop of wheat, by making the root crop follow the 
wheat. 
Again, many plants are DEEP ROOTERS, many are mere SURFACE ROOTERS. 
The deep-rooted plants draw their plant food from the sub-soil; but they draw 
up more than is required for their own use, and thus they leave a supply for 
the succeeding crop, which should be a surface rooter. Turnips, for instance, 
are surface feeders, and in countries where turnips are fed off by sheep an 
abundance of rich plant food is left for a following cereal crop. 
Now, what are the advantages of rotation ? 
1. From what I have told you, you can easily perceive that the yield of 
each alternate crop will be increased. 
2. Insect pests and fungus pests attack each its particular plant. If you 
find some insect devouring the wheat or barley crop, you can entirely get rid of 
it by planting something of an opposite nature on which it will not feed. 
Consequently the insects all die or are driven away in search of their favourite 
food. 
3. The plant food required by one crop is not the same entirely as that 
required by another. Thus there is a saving in manure. 
4. Rotation distributes farm labour throughout the year, and thereby 
economises by preventing extreme activity being followed by periods of idleness, 
and so enables the farmer to employ less labour with a better result. 
5. If you keep dairy or store cattle or sheep, as all good farmers do, the 
rotation enables you to give them a necessary change of food. 
6. Rotation gives you every chance of thoroughly cleaning the land, and in 
a good rotation one year’s crops will be such as will not prevent the thorough 
tilling of the soil, and these crops are, as you learned in Lesson 5, called the 
fallow crops. 
Alternation of leguminous and forage crops with hoed crops preserves 
fertility by means of the vegetable acids of the legumes acting as solvents— 
that is, dissolving the unavailable plant food when ploughed under. 
Cow peas carry several times the weight of roots that cereals do; and as 
they are very much richer in nitrogen than wheat or oats, therefore wheat 
or oats should follow cow peas. Cucumbers take up 2 lb. of potash to 1 of 
phosphoric acid, while pumpkins only take up 3% lb. Cabbages take up 11 Ib. 
of potash to 1 of phosphoric acid ; but maize only takes up 37% to 1, and so on. 
So you see, if you were to grow cabbages continually on a piece of land, 
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