New Nitrogenous Manures.

Otago Witness, Issue 2928, 27 April 1910, Page 9

New Nitrogenous Manures.

TO THE EDITOR Sir,— ln the Otago Witness of April 13 there is a note by your Southland agricultural correspondent under the above heaain<r. There are sever paragraphs in the note, but paragraph five is the one I would like to draw your correspondent s attention to, where be refers to the maxing of calcium oyanaimde with Mr A. D. Hall the director-general of experiments at Rotharaeted, in his book. “Fertilisers and Manures,” makes this reference to the mixing of superphosphate: “As a fertiliser calcium cyanami de has been _ subjected to a series of suffioientlv conclusive trials, which show that on most soils it is almost, but not quite, as effective as sulphate of ammonia, supplying an equal amount of nitrogen. On coils poor in lime, doubtless cyanamide would give comparatively better results, because them the carbonate of lime which is the by-product of the decomposition taking place in the soil would itself be of considerable value. The Rot hams ted soil, however, contains sufficient carbonate of lime to minimi®© the effects of this factor. The chief to the practical employment c calcium cyanamide as a manure is its fight, blow-away character, and the injurious effects upon germinating seeds of the ammonia and other gases- given off when it is first apiplied to the soil. It has, therefore, to be sown on the land alone, and it should be incorporated with the soil a week or so before any seed is sown. For similar reasons it should not be used as a top-dressing, unless mixed with sarth beforehand, though recent experiments suggest that this injection has been exaggerated. It is best to mix the cyanamide

with superphosphate before application to the land; in most cases when cyanamide ia used phosphates will also be required and a mixture of cyan-amide nth from 5 to 11! times its weight of superphosphate can be conveniently made; and forms a good fertiliser for barky or turnips The mixture should be made on the floor of the manure shed' at least a day before the nanure has to be sown; if the cyanamide is carefully handled and covered with uperphosphate, it can be mixed without creating an un r bearable dust. With the slaking of the lime a good deal of heat is developed and the manure begins to steam, but % sprinkling from a watering-pot will help to keep the heat down without rendering the mixture in any way difficult to handle. The heap should be turned over two ox three times to secure a good mixture, and left until the next day to cool off. It .-ema'as in a nice friable condition and undergoes practically no further change if it cannot be sown at once. No unpleasant gases are given off during the mixing; the samples of cyanamide first made contained some unchanged calcium carbide, which *iyea off acetylene on wetting, but this is now avoided in the manufaoturfhg process. Two ■methods, have been adopted to obviate the dustiness; in on© the product is treated with a small proportion of heavy shale or coal oil, in the othen just sufficient treatment with steam is applied to convert the quicklime into slakelime, which gives the. material a more granular form. This Jatted process has the further advantage of decom-posing-any traces of calcium carbide and phosphide that may be present in the original material." Now, I hope that this may meet the eye of your agricultural correspondent for Southland, who will see fch'a* I have gained some useful knowledge by the reading of his notes. —1 am, etc. D. M. [lf "D. M." will refer to cur Southland agricultural correspondent's note again he will observe that he expresses no opinion whatever as to the merits of the exper'ment referred to. He simply summarises the conclusions arrived at by Mr HendricL, the lecturer on agricultural chemistry at the Aberdeen Agricultural College, which the college authorities deemed Of sufficient importance tc warrant theii* printing them in parrphlet form. It is apparent that there is a difference of opinion between two eminent authorities, but it is not for us to decide as tc .vho is right and who is wrong. Suoh eminent authorities on this important subject might well be left to their oww resources. Mr Hendrick's conclusions, how-t ever, have this to recommend them: they are the result of a recent experiment of an exhaustive character, whereas Mr Hall's work is not what_ could strictly be term* recent— "3d. O.W.]