4i4 “QUEENSLAND AGRICULTURAL JOURNAL. [1 Juve, 1902. 
might be said ihat rotation is no longer necessary. But this is not actually the 
case. You may manure and grow grain crops successfully, but by and by a 
limit is reached, and you find that it will not pay you to stimulate the crops of 
wheat to a high productive point, so the next best thing is to grow grain crops 
in rotation with something else. ae 
There are two general rules to be followed when rotation is practised, and 
I have outlined thém already. Fs 
One is: Keep crops which require the same ingredients for their growth 
as far as possible from each other in arotation. The other is: Do not follow a 
root crop with another whose habit of root growth is the same. TI explained to 
you in the 6th Lesson of the Second Book that some plants are suRFACE 
FEEDERS, others deep rooters. As the deep rooters draw up plant-food from 
the subsoil in greater quantities than they need for their own growth, the 
succeeding crop should be a surface rooter, like ee for instance. 
In that lesson I also gave you an example of the four-course or Norfolk 
rotation. By the frequent growth of fodder crops and thorough tillage the 
fertility of the land is kept up. 
Now look at this four-course rotation in another form as given by 
Professor Hedger Wallace in his book on Agriculture for Students. He 
represents it in this manner— 
Fallow Crop. 
Cereal Crop. Cereal Crop. 
Leguminous Crop. 
and then describes how several kinds of plants may be grown in the rotation, 
(1.) An autumn-grown cereal.— Wheat. 
2.) Fallow crop.—Roots, turnips, mangel, cabbage, potatoes, &c. 
(8.) Spring-sown cereals.—Maize, rice, imphie, setaria, &c. 
(4.) Leguminous crops.—Peas, beans, clover for hay. 
- Now let us follow him through this rotation for a light soil. First of all 
the old wheat stubble is broken up by the plough, and the land receives a good 
manuring with farmyard manure and a little phosphate of lime in a very 
slowly soluble form. ‘The manure should be well rotted so that it may not take 
up much room in the soil, and should be applied just before sowing time, 
because light soils are not retentive enough to hold the soluble matters of the 
ene for any great length of time before the crop is able to make use of 
them. 
A fine tilth is then obtained by means of roller and harrow, the weeds are 
collected and burnt, and the fallow is ready (in England) for Swede-sowing in 
May and turnip-sowing in June. All through the summer the soil is kept 
hoed between the rows, and thus the dormant food in the soil is gradually made 
soluble by the action of the rain and air, and the roots greedily feed on the 
active plant-food thus produced, as well as upon the manure which was applied, 
and the nitrogen carried into the soil in autumn by the rain. And by cropping 
the fallow with roots, the active plant-food produced in the soil by fallowing is 
prevented from escaping into the soil. 
Now, here is where sheep come in. ' 
Tn winter these roots will be consumed by the sheep on the land, and so 
the plant-food that has been collected by the turnips from the various sources 
just mentioned will be again added to the surface soil in a slowly soluble form 
for the barley crop of the following year. Clover will be sown with barley in 
