THE OBJECT OF LIMING.

Auckland Star, Volume XLIV, Issue 92, 18 April 1913, Page 11

THE OBJECT OF LIMING.

Farmers should realise that the object of all liming is to increase the. percentage of carbonate of lime in the soil, and it makes litt.e difference in what form the lime is applied so long as it supplies the soil with carbonate of lime in a finely divided state, thorouglily and intimately mixed throughout the soil. .Practically speaking, the whole effect of a dressing depends on this thorough f mixing' of 'minute particles of the lime throughput every part of the cultivated ,soil. Lumps of .carbonate of lime, can produce-practically no benefit till they , have been, weathered and- broken - down ;into fine powder;- and even 'particles _o I bigger than pins' heads are largely j wasted till they have been reduced to powder so. fine that it could not be felt between the fingers. It is owing to the productions of,, this. "der bn j _h.ek_ng'.tKftt'burnt lime has-be.. fouii'd. to", be .0 ffhe'powder. 13----so fine, in fact, th_t it is r very difficult, to handle and spread evenly. In the case of ground burnt lime this difficulty in spreading evenly is overcome, for the unslacked ground lime can .be quite easily spread by a manure distributor, "ariU as every little partijele of the lime slacks where it falls," the whole surface is. evenly covered, with, a thin coat of slacked lime which readily mixes with the soil. This is indeed the only gain in using ground lime instead of ordinary lump lime, but it is an important gain, because it increases the effectiveness 'of the dressing and allows smaller-quan-tities to be used. It must be distinctly borne in mind, however,~that this slacked lime that we have been to so much- trouble in spreading, quickly takes up carbon dioxide 'gas from the air"and is converted back 1 again into carbonate of lime, exactly : the same, chemically, as it was the' lime was 'burnt, but with the advan-" tage of being now in the form of very fine powder. "The change takes place very quickly—in fact, it will commence immediately the slacked lime is exposed to .the air} and in the case of a thin layer spread over the soil practically the whole of it' will be converted into the .carbonate ip. the course of a few days. Now: limesj'pne. being nothing more than carbonate .of lime in a more or less pure form, it stands to reason that if :we .could reduce it to a sufficiently fine powder, it should exercise the same effect precisely as a dressing of slacked lime that has been allowed to remain on the surface of the land for a few days.