POTASH IN NEW ZEALAND

Nelson Evening Mail, 18 May 1917, Page 5

POTASH IN NEW ZEALAND

- MAINTAINING THE SUPPLY. The question of maintaining the supply of potash in New Zealand has been one of considerable importance since the outbreak of war. Plentiful supplies of soluble potash, favourable for use in agriculture without treatment used to come from the mines at Stassfurt, in Germany, but, of course, these are not now available. In an address delivered in Wellington on Wednesday night, by Mr P. G. Morgan, M.A., F.G-S., before the Philosophical Society, he stated that the present scarcity of potash „jji the Dominion did not arise from the JslcHi. that potash itself was scarce. • As a jnatter of fact, potash formed, on the average, .3 per cent of the earth's crust. In New Zealand" available analyses indicated that New Zealand rocks contained, on the average, 2.8 per cent, of potash. That meant that the potash contained in the average rock, if abstracted, would be worth from £3_ to per ton, according to the chemical formation —chloride, sulphate, carbonate, or hydrate. /It would riot- pay, however, to treat the average rock for the potash it contained, as the process ' would' be too costly. From rock unusually rich in potash (10 per cent, or over) the substance would be commercially but experimental work in this connection had not so'far , been commercially successful. The only * rocks in New Zealand known to contain 10 per cent or more of potash "certain pegmatites (very coarse-grained granites), which occurred in Westland, West OtagOj and Stewart Island. Mr Morgan stated that it would be i possible to use as a soil dressing glauconitic greensands, which . usually contained several per cent, of potash, tdgether with a good deal of carbonate of . lime and some phosphate. Thus greensands benefited the soil in three ways. There were, also certain rocks winch could be favourably applied as a soil dressing. Mr Morgan stated further that'mbre use could be made of wood ashes and burnt seaweed or kelp.