LONG-TERM EFFECT

Evening Post, Volume CXL, Issue 56, 4 September 1945, Page 8

LONG-TERM EFFECT

ASH FROM RUAPEHU

Several inquiries have been made recently as to what effect the ash from Ruapehu which has been falling over a large part of the North Island for some time now would have upon the soil on which it fell. The deposit was analysed by Dr. C. O. Hutton, of the Geological Survey Department, recently, and among the constituents were lime and potash, the beneficial effects of which to soil are well known. Mr. N. H. Taylor, of the Soil Survey Department, stated today that the effect of the deposit was a long-term one. The immediate effect of a light dusting of ash such as has taken place in Wellington would be practically nil. Although the dust is fine, it decomposes very slowly. The decomposition of ash erupted from Ngauruhoe had been closely followed, and it had been found that one effect of the ash as it decomposed was to reduce acidity. Mr. Taylor said that although the deposit contains a fair quantity of lime, it •would take a substantial amount to bring soil up to saturation point with lime. Where the ssh fell on pumice country, however, its effect would be very beneficial, and it would greatly increase the fertility of the land. Pumice country was low in cobalt and caused bush-sickness, and this andesitic type of eruption tended to ameliorate this condition. An area of pumice country covered by ash from Ngauruhoe in 1928 had been immediately cured of it. The effect of the deposit would only be felt over a very long term, Mr. Taylor concluded. This was due to the fact that so much of the ash was in a crystal form and crystals were notorious for their slow decomposition. Activity at Mount Ruapehu continues moderate, according to a telegram received today by the Director of the Geological Survey (Mr. M. Ongley) from Mr. A. C. Beck, who is observing at the mountain. "Moderate activity," he reported. "Continuous banner, mainly steam, and little ash."