A SOIL SURVEY.

Sun (Christchurch), Volume III, Issue 882, 7 December 1916, Page 5

A SOIL SURVEY.

WHAT IS NEEDED IN NEW ZEALAND.

SUGGESTED METHODS OF TREAT- - MENT. I -

A paper of practical interest and importance not only to farmers themselves, but to all who are concerned with the] development of agriculture in New Zealand, was presented to the Philosophical] Institute of Canterbury last evening, by Mr L. J. Wild, M.A., F.G.S., of Lincoln Collegee. The first part of this paper gave an outline of the chief advantages derivable from a soil survey, and these, said Mr Wild, mar be summarised as follow: ] —(1) The gaining of statistical information as to the productive capacity of the various parts of the country. (2) The hundreds of soil analyses already I made in this country can be properly j interpreted only in the light of a know-1 ledge of soil formations, from which | the samples have been drawn, which i knowledge is the kind obtained by a j soil survey. (■'!) The successful interpre-i tation of "the results of field experiments j depends entirely upon a knowledge of the extent and characters of the various | soil formations of the district. (4) the I detection and cure of "agricultural mis-j fits" —soils set to grow crops to which j they are unsuited. Part of the work of; a soil survey is to determine the class of i soils suited to the different crops already available, and also to find new; crops suited to soils of special charac- ] ters.

The second part of the paper criticised the methods adopted in the soil surveys of various foreign countries. In particular it was shown that a classification of soils strictly according to geological origin is frequently futile even in countries best adapted to such methods, and especially so in the case of New Zealand—a country for other reasons not adapted lo such methods of treatment.

The writer suggested: —(1) A division of the Dominion into soil regions, based mainly on climatic considerations, with subdivisions (areas), where demanded by important (agricultural) differences produced by geological structure. (2) An independent division, based on the lines suggested by Mr Ferrar at a previous meeting, namely: —(a) Unproductive areas, e.g., the mountains of Southwest Otago; (b) areas capable of being easily made productive, e.g., North Island bush; (c) areas that cannot be other than pasture, e.g., tussock mountain slopes; (d) areas available for cultivation.

Attention should, then, be first concentrated on the last two of these classes of land, and the survey should proceed to mark out on them the separate soil formations. A soil formation is defined as a geographically continuous area, covered by a soil uniform throughout or with only minor exceptions as regards origin, texture, composition, climatic conditions, and profile, and, therefore, as regards all agricultural properties. The formations being determined and minutely described as regards both laboratory and field characters, they are next to be grouped together into series. A series is defined as a fjroup of separate formations alike in the aggregate of their agricultural properties. The formations included in one series may not necessarily be identical in every respect, but must agree in their essential agricultural properties and potentialities. The main advantage of so grouping formations into series is that the results of experimental determinations of crop varieties, maiiurial treatment, and so on, suited to any one formation, may iu general be applied without hesitation to other formations of the same series.

The last part of the paper contained an outline of the soil regions of the South Island, with specimen descriptions of some soil formations and series.