BONES.

New Zealand Mail, Issue 1318, 3 June 1897, Page 5

BONES.

Agriculturists will not require any lengthy statements to convince them that bones constitute one of our oldest and most favourite artificial manures ; indeed, we are not asserting too much by remarking that, owing to results forthcoming subsequently to their application upon grass land, they proved largely instrumental in stimulating inquiry into the principles of agiicultural chemistry, attracting to this indispensable branch of science a sincero interest, and proclaiming its essentially practical character, consequently the position appertaining to bones must be regarded as a particularly distinguished one. Originally, of course, this fertiliser would be employed in a raw condition —that is to say, in its natural state after undergoing a simple crushing process of greater or less thoroughness.

Now, however, supplies are mainly taken by manure manufacturers for dissolving, by which treatment they .become infinitely better suited to the farmer’s requirements, and even those portions remaining imperfectly reduced by the acid, forming the insoluble phosphate of bone manures, are unquestionably superior to the unaltered substance on account of the partial disintegration and decomposition it has undergone; its nature being thereby greatly modified. Nevertheless, very considerable quantities of natural raw bone in the shape of meal are still employed in the field, and for various special objects, doubtless with advantage, but when conditions are normal, and merely ordinary purposes are to be served, we cannot recommend such procedure as the most economical or judicious, because distinctly better returns are obtainable by other means.

Thus, for instance, soluble phosphate in conjunction with the insoluble bone phosphate will generally yield far more profitably even where grass land is concerned, for the nourishing constituents furnished by bones are necessarily comparatively dormant and inert, hence when placed on average soils the plant food would long remain unavailable. We perceive, therefore, that as reasonably rapid action is a factor of primary movement in determining manurial value raw bones on this account are not comparable with many fertilisers of a different class, and the truth we have so frequently insisted upon —namely, the importance of considering the form in which the elements of plant nutriment occur—is once again clearly demonstrated. Bones afford nitrogen and phosphoric acid, both constituents being present in a condition admirably adapted to render them a suitable ingredient for preparing manures. We must not, however, regard them chiefly as a source of phosphoric acid, because, unlike the majority of organic products, they contain a large proportion of mineral matter, the greater part of which consists of phosphate of lime. The nitrogen is found in an animal that after proper treatment is converted into gelatine. Another component naturally existing in bones is grease, and this, when removed, has a separate commercial value, but if permitted to remain in materials to be used agri ju iturally, it exercises an unmistakably prejudicial influence by seriously retarding availability, as the bones are thereby protected from decomposition ; in fact, this body, allied with the hard structure, is responsible for their. slow action upon plants when applied in an unmodified state; obviously, therefore, before using a a fertiliser in any way the fat must be extracted. The percentage of moisture and animal matter (we here refer to adherent gristle, tissue, and. so on) will also vary considerably in different samples, and should be taken into account when ascertaining their money value. Bones richest in these . two items are broken down most readily in the soil, "and consequently are better fitted for direct application. Occasionally some amount of salt is added to bonemeal for preservation purposes, a perfectly legitimate object; but manifestly buyers should pay accordingly, for they would not care to I purchase salt as a substitute for bone.

The so-called boiled bones are frequently brought to our notice in various conditions. These may be considered a by-product obtained in the preparation of gelatine, so evidently a great part of the animal matter is missing, and as a necessary result the proportion of nitrogen has undergone material diminution. At the same time the relative amount of phosphoric acid is correspondingly increased, whilo the physical character has become so altered that they may now be ground to impalpable powder with the utmost ease. Indian bonemeal is produced from materials harder or rather less tough Ihaivother descriptions. Moreover, small quantities of gristle, flesh, or fat are present. Therefore it is possible to attain a fine condition more speedily and satisfactorily, notwithstanding the percentage of moisture may not be widely different. These properties render this, description of bone invaluable in preparing pure dissolved bones ; indeed, without something of the kind the high class and admirable products now procurable could scarcely be produced. —Mark Lane Express.