FERTILISER FUNCTIONS

Sun (Auckland), Volume III, Issue 868, 11 January 1930, Page 25

FERTILISER FUNCTIONS

BALANCING PLANT DIET INCREASING USE me essential crop-feeding plant foods used to supplement farm yard manure are known as fertilisers, and are classed as nitrogenous, phosphide and potassic, according to the predominent ingredient they contain. These three substances or ingredients have been scientifically proved and practically demonstrated to be the main requirements which have to be provided in adequate quantities and suitable forms to maintain a high degree of fertility in the soil. There are other ingredients, such a sulphur, magnesia, iron, chlorine, etc., but as they exist in sufficient supply in all ordinary soils it is not necessary to take them into account. Lime, howevsr, is essential, not so much as a plant food, but as a soil improver and sweetener. The function of the nitrogen is to ac‘. as Nature's tonic' plant food. It is the most active of all kinds of fertil sers, stimulating the life force of plants to growth and development. Look at a cereal crop after a spell of cold winds. A sorry sight it presents, with leaves tinged with yellow, and the whole plant without apparent vigour. Given a small dose of nitrogen and rain and note the quick charge, the leaves vivified to a healthy green, and the whole plant stimulated to new life, states a writer in "Farm, Field and Fireside.” But, ns might be expected from the active function of nitrogen, it has to be used with discretion. An excess, unless counterbalanced by phosphates and Potash, leads to undesirable results, su;h as the growth of too much straw *o the detriment of the quality of the grain, dela.y In the ripening process and tends to cause "lodging.” The function of phosphoric acid, which is the fertilising ingredient in Phosphatic manures, is no less Important than that of nitrogen, though not so active in character. It Is a vital Part of plant life. No crop capable of affording nourishment to man or beast can be produced without the Presence and co-operation of phosphoric acid. Its action, applied to the sod in appropriate form and adequate quantity, is manifest. Its special "tactions are to nourish the early sruwth of young plants, to stimulate root formation, to strengthen stem structure, to hasten the ripening proems. to improve quality of crop, and especially to add to the nourishing character of grasses and fodder crops. Tor the successful cultivation of roots the help of phosphoric acid applied ! n Phosphate manures is considered indispensable. The special function of potash is to enable plants to resist diseases and to improve quality of produce. It increases the flavour of fruits, and renders the straw of cereals more elastic, knd thus less liable to lodge. Combined with phosphates its use has Proved a potent factor in redeeming Door grass lands. The leaves of crops grown in soils deficient In potash ar e pale in colour and are liable to attacks of fungoid disease. The valuable functions are now more fully appreciated, and as a consequence the use of potash fertilisers in England is ■ncreaslng from year to year.