TO SAVE THE SOIL.

Forest and Bird, Issue 50, 1 November 1938, Page 14

TO SAVE THE SOIL.

(By E. V. Sanderson.)

EROSION AND ITS REMEDY—AN EXPERT SURVEY.

A STATE Commission has now been appointed whose work will be to make a general survey of soil and forest conditions in order that steps may be taken to arrest the already serious erosion of steep country in New Zealand. The most damaging phase of this is not so much the scouring away of valuable land adjacent to river banks, bad as this is, but the less noticeable loss of top soil on any land having a gradient. Much of this moving topsoil finds a temporary resting place in the valleys and what little plain country we have, but the finer and more precious clay and silt quickly reaches the sea, as anyone may see by the discolouration of the ocean after rain. This process, originally slight, has been accelerated in an alarming degree since the white man began the work of timber-felling and landclearing for cultivation and stock raising. Injudicious destruction of the vegetative covering on watersheds by milling, fire and grazing animals, both domestic and wild, brought disaster to hill and plain alike, and ruined once safe and navigable rivers.

Reclothing the Country. —The logical remedies must be:— 1. Milling with a view to a perpetual crop; 2. Drastic enactments making fire lighting illegal in many cases where it is now practised; 3. The elimination of grazing animals in forests and on steep slants, and hill country above a certain altitude; 4. The abandonment to nature of all rough hill land which has been wrongfully opened up to settlement, and the exclusion of fire and plant-eating animals therefrom.

Those areas of abandoned land which are reasonably accessible and economically adapted to timber growing could be planted with suitable trees as funds permit. The rest could well be left to nature to heal. This she will do in her own leisurely manner if fire and planteating animals are excluded. Where the original forest has entirely disappeared the process of reclothing the soil will commence with an initial growth of what is only too often contemptuously termed scrub, such as manuka,

tauhinu, fern, wineberry, mahoe, and so on. This covering forms a check against excessive water run-off, a protective mat and sponge far more effective than insignis pine and other exotics in which foresters seem to place all their faith. Such a floor covering would hold the remaining soil in situ and in time produce additional top soil. In the course of time larger and larger trees will germinate and prosper, nursed and sheltered by the so-called “rubbish,” which is nature’s method of fighting against man’s stupidity in order to replace her forests and save her precious topsoil that she has taken countless ages to form. The authorities are to be congratulated upon their recognition of the fact that erosion is the most serious physical peril that threatens the country, and that they have at last set up this commission, which would have been strengthened by the inclusion of practical farmers with a knowledge of high country. The first necessary duty before it is to demarcate the land with a view to putting the various areas to their most economical uses, as originally suggested by the Forest and Bird Protection Society and so earnestly advocated by the press in general. All those who have the national interest at heart will wish the Commission success in their work, in the belief that knowledge and vigour will be brought to bear on the task of saving the soil.