LIFE AND PHOSPHATES

Sun (Auckland), Volume IV, Issue 968, 10 May 1930, Page 31

LIFE AND PHOSPHATES

AN ESSENTIAL FOOD GREATER USE NECESSARY “Life, without phosphates, would be impossible as we know it,” states a writer in the Fertiliser Journal. “About one-half of every hone in one’s body is phosphate. Phosphate circulates in the blood and supplies the muscles, nerves and brain with vital energy. Invention, art, literature, in short, all the products of thought, and work, depend on an adequate supply of phosphates. This supply comes from our daily food, whether animal or vegetable; in the first instance vegetable, since the animals we eat feed on vegetable matter. We can easily understand, therefore, how vitally necessary it is that the soil producing the basic elements of life must contain plenty of phosphates. Does it? Except in very uncommon soil formations it does not. Natural supplies of phosphate, even in virgin soils, are very meagre. They are quickly exhausted by cultivation and must be replaced artificially if fertility is to be maintained. Fortunately for mankind nature has concentrated in certain parts of the world—notably in North Africa, North America and some islands in the Pacific—enormous deposits of phosphate, the mineralised remains of animal life in past ages of the world’s history. It can be truly said that, but for these deposits and their discovery by man, the human race would today be in a very bad way indeed. As it is, thanks to this provision of nature, supplies of phosphates are abundant ancl in no danger of early exhaustion. Discoveries of further deposits continue to be made, as the result of continuous investigation of nature’s mineral secrets. ENGLISH RESEARCH To Liebig in Germany, and to Lawes in England belong the credit for discovering a process by which mineral phosphates are made soluble in water, and immediately fit for absorption by plants. These jdoneers found that the mixing of a ton of ground phosphate witli a ton of sulphuric acid produced nearly two tons of a readilysoluble fertiliser, which was called superphosphate of lime. This discovery revolutionised agricultural practice and has led to a world consumption of superphosphate, reaching today the very large total of about 14 million tons. The particular merit of watersoluble phosphate is that, through the action of rain-water, it becomes distributed through the upper soil in a very perfect manner, such as obviously cannot be obtained for any solid powder however finely ground or carefully prepared and applied. The dissolved phosphates quickly combine with other substances in the soil, and, while remaining available to the plant, are no longer soluble in water and cannot be washed away and lost for" thorough distribution and quick results, water-soluble phosphates stand pre-eminent over all insoluble forms. ACTION OF SUPERPHOSPHATE In the case of water-soluble phosphate the sulphuric acid used in its preparation is not, as might be supposed, deposited in the soil as acid. A good deal of error and misrepre- i sentatiou has arisen on this point. I What happens is that the whole of ■ this acid combines in the process ot'; manufacture with the insoluble mat- j ter in the raw phosphate to form completely new chemical substances. Principal among these is sulphate of lime, a neutral salt, and itself of distinct fertilising value. It has been definitely and abundantly proved, by trials during many years in this country, on the Continent and in U.S.A.. that -superphosphate does not cause soil acidity, but in many cases ac-tu- j ally reduces it. There should be no ! room for doubt or misrepresentation > on this point. That soil acidity does ! exist, particularly in lime-poor soils, t is unfortunately true, but it is due ! to other causes, and can only be ade- i quately corrected by occasional dress- j ings of lime, and, where necessary, by | proper drainage. . - When choosing from any of the complete fertilisers marketed by reputable j vendors, the farmer should make sure that his choice contains a reasonably good proportion ot water-soluble i phosphates. 51ost of the nitrogen and i practically all the potash will be readily soluble, and the phosphate must be equally available to give a , manorial balance, and for the plant to j find all the nutriment it reqiurea from j the start. (