242 GEOLOGICAL SURVEY 
Errects oF CaLtcarEous Manures. 
Every thing connected with lime has been recently so thoroughly discussed, and the results of 
so many successful applications have been published, that liming and marling are no longer con- 
sidered in the light of experiments, in the State. 
Lime, in some form or other, is recognized among the fertilizing ingredients of every country 
where agriculture has made any real progress, and its effects have, on this account, been studied 
with corresponding care.” 
Without entering into the discussion of the benefits to be derived from the application of lime, I 
will endeavor to present, in the simplest manner possible, the theory of the action of calcareous 
manures in general, as the surest guide to their proper use. 
1. A certain amount of lime is found in the ashes of all plants, and may be fairly reckoned 
among theit necessary constituents. 
2. It promotes the decomposition of vegetable matter, such as the roots and other remains of pre- 
ceding crops; and by thus bringing it into that peculiar state in which it absorbs nitrogen, it con- 
verts inert vegetable matter into a highly active nitrogenized manure. 
Decomposition is assisted by the neutralization of the organic acids, such as galic acid, which 
are the result of the process, and are highly anticeptic. It also acts as a solvent, as the alkalies 
do, of the silicates, and hence, probably, its effects on clays. 
3. It acts mechanically upon arable lands, thereby altering their physical properties. It dimin- 
ishes the tenacity of stiff clay soils, and materially lessens their retentive power, while, on the 
other hand, it stiffens and renders light soils more retentive. 
Knowing that lime, which is a simple manure, adds but one constituent of plants to the soil, and 
even that one is taken up very sparingly, no one will think of applying it directly to the roots of 
erowing plants, as they would complex manures, that yield several elements, in small quantities. 
Its effects on vegetable matter, distributed through the soil, such as roots and stubble, point directly 
to the proper mode of applying it, as well as the proportion in which it should be applied. Expe- 
riment, which is the safest guide, has indicated 150 bushels per acre, of pretty good marl, as the 
quantity that may not be exceeded, on the ordinary soils of the State. 
Where vegetable matter abounds, and there is great depth of soil, it is difficult to fix the limits, 
as may be seen in the western prairies, where cotton flourishes literally, in marl, intermingled 
with black vegetable mould. Other things being equal, stiff, clayey soils require a larger dose. 
Of caustic lime a greater quantity than 40 bushels an acre would be unsafe, in our climate, on 
common soils. This contrasts strangely with the dose of from 200 to 500 bushels, common in 
England. Whether lime be used in the caustic state or in that of marl, intimate mixing with the 
soil near the surface is of the utmost importance. Marl should be allowed to remain exposed on 
the surface as long as possible, before it is ploughed in. 
The inquiry is often made, do not caleareous manures exhaust the soil? They do, by causing 
it to give up freely the organic matter it contains, and this is the prime object of the application. 
*For a full examination of the subject see “ Essay on Caleareous Manures.” 
