SOIL EROSION

Evening Star, Issue 25679, 31 December 1945, Page 2

SOIL EROSION

NEW CYCLE FEARED AREAS ON EAST COAST The seriousness of New Zealand’s erosion and soil conservation problem was indicated by the director of the Grasslands Division of the Department of Scientific (Research, Mr. E. Bruce Levy, recently when he said that a new cycle of accelerated erosion was in the offing and' would continue to aggrade the valleys, build new flats, and add to existing ones unless the erosion was brought under reasonable control. Mr Levy is a member of the central standing committee which advises the Soil Conservation Council. “ The most serious erosion is undoubtedly in the Poverty Bay Catchment Board area,” said Mr Levy. “Steps on a national scale must be taken there immediately, for there is a real danger that all the fiats of the Hast Coast may become inundated by soil and debris from the hills behind them. VAST TRACKS MENACED.

“Controlled erosion may yet bo a service to New Zealand in plain building, in reducing steep, difficult hill country to an easier grade and in filling deep gorges and ravines that are a menace to stock; Should that erosion proceed out of control, ruination faces vast tracks of valuable, highly-produc-tive fiat lands of the Poverty (Bay area. The same is true of Hawke's Bay and other parts of the North Island, where mudstone, papa, or shallow ocean-bed formations constitute the backbone of the country. Where the backbone is hard rock the damage is not so real, but disaster faces tne lowland where a loose gravel structure dominates the mountain ranges.” ■ Erosion there gave rise to gravel screes which spread over the land, and they were to be dreaded more than the soft mudstones, papa, and sandy deposits, because ages must elapse before sufficient soil was built around the stones to farm the land successfully, said Mr Levy. The gravel screes must be brought under complete control, or a new erosion cycle would continue to build the vast gravel valleys, plains, and fans that characterised the foothills and adjacent land along the main greywacke ranges of the North and South Islands. ENGINEERING PROJECTS. •

“The research projects are in the first place essentially engineering projects, to be assisted l by grass, snrubs, trees, or afforestation,” said Mr Levy. “ Stabilisation of the gully and control of the normal river ilow. are the two prerequisites to gaining stability once more, both in soil and vegetative cover. Research should precede big remedial operations, but such research should be merely the vanguard of largescale control operations which may rapidly become so simplified that the farmer becomes his own engineer and his own authority in the matter of grasses to sow, the types of trees necessary and how to plant them to the best advantage.” Mr Levy said research and extension, which should continue until control of the problem was assured, should go on hand in hand under the co-ordinated control of catchment boards, the Soil Conservation Council; and the State department. LARCE-SCALE MEASURES. • An extensive scheme for dealing with a number of.areas was detailed by Mr Levy, who said that, to implement the outline of soil conservation research, the scheme must be a bold one and must inevitably work in with largescale control measures. It would be necessary to set up main bases and outstations, to possess machinery, plant, and materials, and to have technical and manual staff. The cost was difficult to assess, but a vote of £IOO.OOO would be necessary to implement the scheme, with an annual maintenance vote of £50,000. With that the council, through the various boards and collaborating State departments, could carry out much pioneering research on a scale that would give a good practical lead to the main .problem of soil erosion and cbnservation.

“ In this research .and development work it is absolutely essentia] to put all the necessary money, labour, and orsranising ability into each project so that failure, if any, cannot be ascribed to lack of funds or to careless and indifferent mnuaqremcnt and organisation,” said Mr Levy.