LIME AND PHOSPHORUS

Otago Daily Times, Issue 21986, 22 June 1933, Page 3

LIME AND PHOSPHORUS

By R.A.S.C

The question has been asked. Which ofthe two soil-improvers is the better for the general run of'New Zealand soils —lime or a phosphatic fertiliser? One cannot answer such a question otfhand. Generally speaking, there are few soils in the Dominion which would fail to respond to liming, or in the alternative, to a dressing of some fertiliser containing phosphorus. Some chemical manures such a sulphate of ammonia and Kai.nit use up the lime in the soil, while all fertilisers, by increasing the crop, increase the consuption of lime. , , . To-day, grassland is the stand-by of all farmers, and it behoves us to maintain its nutritional qualities, as it is widely recognised that many diseases of farm animals owe their origin to the shortage of essential minerals, particularly calcium and phosphorus. Experts both here and abroad, emphasise the importance of ensuring an adequate lime soil content. Cows, suffering from milk-fever have a deficiency of. calcium in their blood, while some sheep troubles are due to a lack of lime in the herbage. Sterility, abortion, and many bone diseases among stock occur not infrequently on starved grasslands. Briefly put, lime' may be said to have a mechanical, chemical, and biological action, and the importance of n systematic application of this invaluable soilimprover, and fertiliser to lands which are at present in lack of it should be apparent to all agriculturists. When this need is supplied,, many of the ailments from which stock suffer, often caused from lack of this very necessary substance in plant food, will be avoided. Acidity of the stomach, often met with amongst cattle, is attributable to want of alkaline matter in the food supply. Malformations at birth, particularly with foals and lambs, can also be traced to the same cause. Lime is necessary to neutralise the acids formed from decaying vegetable matter, and may be safely added to the soil at any time of the year. Lime is death to harmful fungi, like finger-and-toe or club-root, while unlocking stores of nhosphate and potash in the soil. There is no doubt that practically all New_ Zealand soils require phosphorus, particularly as we export so much of it in meat, dairy produce, etc. The best method of supplying phosphorus or any other mineral to stock is undoubtedly by top-dressing grasslands with suitable fertilising mixtures. Failing this, something might be attempted by utlising certain stock licks. There is little if any risk of making the soil sour by using superphosphate, although some farmers contend otherwise. Sir John Russell says: “A considerable number of tests ■were made with superphosphate by the Rothamsted Experimental Station in different parts of Britain but even the most, delicate methods failed to reveal any increase in acidity that could possibly affect the crop.” Professor Connor, of the United States Department of Soils and Crops, says: “ Far from increasing the acidity of a soil to which it has been applied, superphosphate assists in correcting the fault, more especially in cases where the acidity is of a mineral nature. It is often assumed that soil acidity arises from the use of fertilisers, in the manufacture of which sulphuric acid is used. Investigations prove that such is not the case, but on the contrary, superphosphate, that is to say, phosphate rendered soluble by dissolving in sulphuric acid is an effective corrective for certain forms of soil acidity.” Professor Harper, of the . Indiana Experimental Station, writes: “It is sometimes said, that the continued use of superphosphate will make the soil acid r sour; This is an assumption contrary to the facts, so far as the actual results are concerned.” Superphosphate does not cause acidity, and there should be no room for doubt , or misrepresentation on this point. It should be clearly understood that there are many different elements required to provide complete sustenance to plants, and through plants to animals grazing—such, for instance, as phosphorus,.nitrogen, potassium, calcium, iron, sodium, chlorine, iodine, etc.,' all being necessary to maintain, health and vigour in plants and-animals. Fortunately, most soils have ample supplies of these essentials except lime, phosphorus and potash, and possibly; in less measure, nitrogen.