SUGAR CANE AND ITS CULTIVATION : 
—— aaa 
OuLrivaTIon. 
Land for cane growing requires plenty of tillage. Not less than 
four deep cross ploughings should be given, and then the soil should 
be well worked up into a fine tilth by harrowing and rolling. Sub- 
soiling to a depth of 20 inches or more on deep alluvial soils has been 
found to yield as much as 20 tons more cane per acre than from similar 
land cultivated in the ordinary way. 
Two great factors in the preparation of our older cane lands are 
lime and green manure. » é 
/ 
Owing to the long-continued growth of cane upon the same land, 
and also, in some instances, to the continued use of acid fertilizers, 
such as sulphate of ammonia and superphosphate, the bulk of our older 
cane soils in Queensland have become acid in reaction. This has 
been exhibited time after time in analyses of soils made by the agricul- 
tural chemist and by the Sugar Bureau. After ploughing out the 
stools it is, therefore, wise in most instances to apply lime, and it also 
has the advantage of increasing the purity of the.juice of the succeeding 
cane crops. There are many other benefits to be obtained from a dress- 
ing of lime, which may be summarized as follows :— 
(1) It acts-on dormant mineral matter and renders available 
phosphoric acid and potash which would otherwise remain inert. 
(2) Acts on, organic matter and converts part into nitrogen com- 
pounds available for the crop. (8) Enables the plant to make the 
greatest use of artificial fertilizers. (4) With moisture and warmth 
it favours the maintenance of abundant bacterial life, especially 
those forms which aid in nitrification. (5) It develops the activity: 
of root bacteria in leguminous crops. In soils with an acid reaction, © 
the fixation of nitrogen from the air is frequently at a standstill. 
(6) Improves the mechanical condition of the soil. Stiff clay’ 
soils are rendered more friable, less adhesive, and porosity is’ 
increased, so that its cultivation can be more easily undertaken.  ~ 
Lime is usually applied to the soil in the following forms :— 
(a) Burnt lime or lime oxide. (b) Air-slaked lime—i.e., burnt 
lime that has been allowed to gradually slake in the air, and which 
ultimately becomes lime carbonate. (¢) Water-slaked lime (lime’ 
_ hydrate). (d) Pulverized limestone (lime carbonate). 
The growth of green manure crops is a form of rotation, and is not. 
yet sufficiently practised in Queensland. It is also a,means of restoring. 
humus to old cane lands, and is a prime essential in the making of a 
fertile soil. 
Humus benefits the soil—(1) By augmenting its water-holding 
capacity. (2) By increasing its warmth. (8) By bettering its texture 
and being a controlling factor in the determination of fine earth. 
Humus in the soil is lowered by:—(1) The continued growth of ‘ 
crops. (2) Bare fallowing. (8) The continued use of commercial’ 
fertilizers... _ : , 3 any 
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