THE FARM.

Kaipara and Waitemata Echo, 30 October 1914, Page 8

THE FARM.

AVAILABILITY OF FERTILISERS

The value of a fertiliser for crops does not depend on its total percentage of ammonia, phosphate of lime and potash, but upon the percentage of those constituents that the growing crop can utilise. This is the point that a farmer has to look at when considering the efficacy of an artificial manure. There are a good many substances that contain a high percentage of one or the other fertilising constituents but the constituents are in such an inert form that they afford little or no nourishment to the crop. They "analyse well," but are bad fertilisers. A glaring instance of this class of substance (the "Mark Lane Express" points out) is ground leather. It contains a very large percentage of ammonia, but decomposes so slowly that it has no right to the title "fertiliser." The plant asks for food and is given not exactly a stone, but something nearly as hard. With the present system of intensive cultivation, in which large quantities of expensive fertilisers are bought, the farmer uses the fertilisers to feed the growing crop or the rotation, and generally not with the object of permanently enriching the land. His object is to turn over his expenditure on manures quickly by getting it back with a profit by the increased crop, and therefore, as a rule, the modern farmer uses fertilisers that act on the first crop rather than those which become available very slowly. He buys and uses manures for prompt profit, and not for posterity.