236 QUEENSLAND AGRICULTURAL JOURNAL. [1 Ocr., 1902. 
more commonly termed, quicklime. This expulsion is worth remembering, as on 
the first opportunity lime takes in the water and carbonic acid driven out during 
the burning process, and gives out the heat received in the kiln. The effect 
this has on the soil will be seen later on. Other carbonates of lime are found 
besides limestone, such as chalk (called whiting when ground), coral, marble, 
oyster-shells, and shell sand. Lime derived from the latter generally contains 
too much sand to be of any great value for agricultural purposes, unless procured 
at a very cheap rate. 
Such lime is a hard, heavy substance, greedy of both water and carbonic 
acid. It absorbs large quantities of water without becoming wet, and crackles 
and hisses and behaves in a life-like manner ; hence the name of quicklime. 
Slaked lime is a powerful alkaline substance used in many ways. Mixed 
with sand and water, it forms the mortar used for building purposes. 
In agriculture lime is generally put on the land at the rate of 1 to 5 tons 
per acre. Finely pounded lime unslaked, is sometimes applied, and in this 
form produces more powerful effects. Lime ought to be harrowed into the soil 
immediately it is applied, so as to cover it up from the air, from which it would 
absorb carbonic acid gas and speedily be converted into carbonate of lime: 
When covered up by the soil it takes the carbonic. acid from the decaying vege- 
table matter or himus, hastening the process of decay, and thus liberating 
hydrogen and nitrogen. This is rather important, as when the liberation of 
both is simultaneous and slowly effected they unite in proportion of 8 of 
hydrogen to 1 of nitrogen, forming ammonia—a_ very valuable plant fertiliser. 
Unfortunately, there are conditions under which this formation is not always 
certain to result, such as lack of moisture, so that lime may sometimes destroy 
the vegetable matter in the soil to no good purpose. 
Some generations ago farmers in the old country discovered that great 
crops of grain could be grown by the aid of lime, and they used it unsparingly, 
even although they had in many instances to convey it from great distances. 
For atime they succeeded in producing heavy crops, because the soil was full 
of manure and humus, but by and by, they found that lime had ceased 
to work miracles, and, though some people tried to make it do what it 
once had done by doubling the quantity applied, it came to be admitted 
that lime had not the beneficial effect it once had. Later on it was 
found out that, beyond supplying the small quantity of lime necessary 
for the growth of plants in soils where it naturally was deficient, the 
lime had been decomposing all the vegetable matter—the only store of 
nitrogen in the soil—so that it had now nothing in it but mineral food, viz., lime, 
phosphoric acid, and potash, &e. Though the lime did not supply any nitrogen to 
the soil, yet it produced, for every ton applied, much the same effect as the appli- 
cation of so many hundredweights of nitrate of soda or sulphate of ammonia. 
The difference in the condition of the soil after a crop grown by the application 
of lime and one grown by the application of nitrate of soda or sulphate of 
ammonia was, however, very great. In the one case the soil had to grow a 
heavy crop at its own expense; on the other the crop was grown by aid of the 
plant food inthe manure supplied. This action is, no doubt, what has given 
rise to the old saying that ‘lime enriches the father, but impoverishes the son.” 
The application of large doses of lime to light sandy soil, or to soil that has 
become exhausted through continuous cropping without backing it up with 
fertilisers, is a great mistake. It is something like applying a whip to a done- 
up horse—trying to take out what is really not there. An old couplet says 
that “ Lime and lime without manure will make both farm and farmer poor.” 
In applying lime to the soil, care must be exercised as to the nature of the 
soil on which the application is to be made. | have known of some cases where 
as much as 10 tons per acre was applied without any bad result, and others 
where half that amount practically ruined the soil for certain crops, such as 
oats end barleys. The only rational cure for land that has been what is termed 
burned with lime is to supply large quantities of farmyard or nitrogenous 
manure. 
