Phosphates and Life.

Otago Daily Times, Issue 21245, 28 January 1931, Page 3

Phosphates and Life.

THE CHEMIST COMES TO NATURE’S ...AID.' DISCOVERY OF PHOSPHORUS. One day in the year 1669 in an attic in one of the wooden houses of which the mediaeval city of Hamburg was composed there stood an old man gazing at a small lump of some substance that shone faintly in the dim light of the room. In one corner of the attic a brazier glowed, the walls were lined with jars and retorts, on the table, thrust away from the object ■which so interested the solitary occupant of the room, were charts and parchments covered with cabalistic signs. The attic was the chamber of an alchemist, and Brandt the alchemist had discovered the philosopher’s stone. Ha was mistaken. The philosopher’s stone still eludes mankind. And, though perhaps he did not think so, Brandt’s discovery was far more important, for he had isolated phosphorus, without which life as we know it would be impossible. Brandt was only just the first. Soon after other alchemists, searching for the philosopher’s stone, even as he had done, stumbled on his secret. But, strange to say, the form in which phosphorus is nearly always found, the compound of oxygen and phosphorus which we called phosphoric acid, was not discovered until over 150 years had elapsed. PHOSPHATES OF LIME. Neither phosphorus nor phosphoric acid is found in an uncombined form in Nature' but is always united with some base or alkali, chiefly with lime in the form of phosphates of lime. The mother source of phosphate of lime is supposed to be a mineral called apatite, but as a matter of fact all soils contain a certain amount of phosphate, though usually in very meagre • quantities. Indeed this must be so, for otherwise, as we have seen, plant. life, and hence animal life, could not exist. However, for millions of years the world got along very happily on the small supply of phosphates that was in the soil, and no doubt would have continued to do so, but that the advent of mankind con-

siderably disturbed the balance of Nature, The march of civilisation, the everincreasing population of the world, and the intensive methods of cultivation, which the latter necessitated, soon proved that the supply of phosphates in the soil was not enough. It had to be augmented, and mankind looked to the. chemist for a way out of the difficulty. And lyekily indeed for mankind both the men and the means were at hand. This supply is to-day augmented by the use of superphosphates and other phosphatic manures. The chemist is still aiding nature in her efforts to supply the wants of man. In the great fertiliser manufactories the man of paramount importance is the chemist, and, while we speak of fertiliser works it would perhaps be more correct to describe them as “ chemical works.” The increased productivity and wellbeing of land fertilised with superphosphate is easily understood when we consider the highly important role of phosphorus compounds in both animal and vegetable life. Readily observed are the changes brought about in crops and pastures by the adequate use of this easily available and hence quick-acting fertiliser. Not less marked by the observant are the consequent improvements to live stock fed upon those enriched plants. If we consider the fact that the phosphoric acid of bone, muscle, brain, and liver amounts to the large proportion of 60 per cent, of the ash of these structures, the reason of its importance in agriculture becomes clear. Phosphates enter into the preparation of the digestive juices and the utilisation of sugar, while the body fluids • are kept at a neutral or mildly alkaline state by the influence of the phosphates of sodium. Phosphates circulate in the blood and supply muscles and nerves with energy. Art, invention, literature; every phase of human thought and endeavour depend on an adequate supply of phosphates. Animal diseases, due to deficiency of phosphates, are common in certain parts of the world, and the free use of phosphatic fertilisers, in these cases, has provided a striking remedy. The introduction of phosphates as manure increases the activity of the bacteria which ‘obtain nitrogen from the air, resulting in an increase of the soil nitrogen. This fact

alone will account for the predominance of phosphatic manuring. ■ Careful and exhaustive researches in laboratory, greenhouse, and field have shown that soluble phosphatic fertilisers not only ' provide more quickly available phosphoric acid than that already in the soil, but also perform a number of other important functions which have both direct and indirect effects upon the crop. The stimulation of root growth enable the plant, especially when in the seedling stage, to withstand adverse climatic conditions. Where the crop season is of relatively short duration, the quick maturity of the crops is often the main factor to be considered, and, therefore, success may largely depend' on the liberal use of readily available phosphatic fertilisers. The tendency of phosphoric acid to increase the proportion of grain to stalk is one of its most impor- _ tant functions in the growing of cereal crops. This action of phosphoric acid is directly opposite to that of nitrogenous fertilisers, which tend to delay maturity and promote the growth of stalk and forage at the expensed the fruit. -i' . The presence of the phosphoric acid is also essential for the formation of chlorophyll, the greeen colouring matter which in plant life fulfils the functions that blood does in animal life. Other effects which soluble phosphates have upon the soil, and indirectly upon tho crop, are the altering of the solubility of other soil constituents, influencing the growth of soil bacteria and nullifying the injurious effect of certain toxie organic bodies formed in the soil. Also protoplasm, that essential part of both , animal and vegetable life, can exist only if the plant is supplied with sufficient phosphoric acid to enable it to function properly. In plant life, as' in animal life, the most important constituents are the phosphatic salts. These salts occur in their most easily assimilated form in superphosphate. We have'thus seen that phosphates are vitally necessary to life. That Nature, while putting a very limited supply of phosphate in the soil where it was most <’ needed, has provided vast accumulations in places accessible to man. And that it is owing to the discoveries of chemistry that man has been able to use these accumulations. . ...