SERPENTINE SUPER

Otago Daily Times, Issue 27568, 9 December 1950, Page 4

SERPENTINE SUPER

THE FARM

Value To Crops And Pasture

This year local phosphate works have processed 1500 tons of serpentine superphosphate which will be sown with a number of crops and topdressed on pastures throughout Otago and Southland this season If this material is up to the standard of that with which trials were carried out from 1939 to 1945, then local users will undoubtedly secure beneficial results. This view..was expressed by Mi A. G. Elliott, of the Extension Division, Department of Agriculture, in a statement to the Daily Times on the value of serpentine superphosphate.

Serpentine super was composed of a mixture of three parts of superphosphate plus one part of ground serpentine, Mr Elliott said. The latter contained magnesium, silica and a trace of cobalt. Its value as a material for use in reverting water-soluble phosphate was investigated in July, 1939, when, as a result of encouraging reports received from overseas workers, an experimental lot of this fertiliser Was processed by an Auckland company and used in a series of trials laid down by the Department of Agriculture in the North Auckland, Waikato, North Taranaki and Southland districts. In the following year an additional series of trials was laid down, including applications on pastures and crops, among which were wheat, oats, barley, potatoes, turnips and swedes. In 1941 a general summary containing the results from 237 co-operative field experiments was published, and the following recommendations were made':—

1. Serpentine superphosphate should be a useful fertiliser for pasture topdressing in the heavier rainfall districts. In North Taranaki, Waihi and North Auckland it gave better results than superphosphate. 2. It is a safe reverted phosphate for use on all crops liable to germination injury. 3. It gave equivalent results with superphosphate on most of the common farm crops. ’ 4. Its superior physical condition makes it easier to sow, more pleasant to handle, safer to store, and less damaging to bags than superphosphate. 5. The magnesium and cobalt content have a definite value. During the war years, when every effort was being made to maintain production of essential foodstuffs and to husband ’ our dwindling sources of phosphatic fertilisers due to the capture of Nauru and Ocean Islands by the Japanese, the National Council of Primary Production recommended that all superphosphate processed in the North Island should be reverted with serpentine, thus making the use of serpentine superphosphate compulsory. In the South Island, where an effici-ently-processed lime-reverted phosphate was available, and serpentine

supplies were not easily :ecured, the compulsory clause was not introduced, but rationing of all phosphatic fertilisers was in force. In view of the satisfactory results secured over a wide range of soil types and climatic conditions with serpentine superphosphate, its use could be .recommended, particularly, in the higher rainfall districts, and where storage and physical condition is of such importance. Mr Elliott said. -In addition to its phosphate content, tfhe inclusion of the trace elements, magnesium and cobalt, in serpentine will be a valuable addition in many districts where these have been found to be deficient. • .1