STUDY OF SOIL

Bay of Plenty Beacon, Volume 11, Issue 32, 23 May 1947, Page 7

STUDY OF SOIL

DIFFERENT TYPES ADDRESS TO YOUNG FARMERS Soil classification was based essentially on inherent features of soils themselves so that a pedologist could recognise any type wherever he happened to be, stated Mr R. E. R. Grimett, superintendent of the Hamilton Soil Fertility Research Station, in an address to young fanners attending the Waikato Winter Farm School at the Claudelands Showgrounds. “Most of our soils,” continued Mr Grimmett, “are either of the skeletal or immature type, or of the peaalfer or leached type of which podsols, perhaps one of our most frequent types, are a well known example. We have very few of the pedocol type, though some of our estuarial and arid inland soils of Central Otago have some of their characteristics. The Soil Survey has now issued or is issuing a complete series of soil maps covering the North Island on a scale of four miles to the inch, and all instructors in agriculture are receiving sets in their own districts.

“Soil fertility is related to land usage,” said Mr Grimmett. “It may be increased or diminished; replenishment is by disintegration of minerals and uptake by deep rooted .plants, but chiefly under our climatic conditions by the application of fertilisers and soil amendments such as lime and organic matter, combined with stock management which can maintain in continuous circulation a rich store of plant nutrients, especially nitrogen. “The fertility of soil is defined in that excellent book ‘Soils and Men,’ the year book of the United States Department of Agriculture for 1938, as follows:—‘Fertility of soil—The quality that enables a soil to provide the proper compounds in the proper amounts and in the proper balance for the growth of specified plants, when other factors, such as light, temperature and the physical condition of the soil are favourable.” “You see then,” continued Mr Grimmett, “how difficult it is to measure fertility when it is subject to so many qualifications. In the Waikato it may be assumed that we are generally concerned with measuring fertility in terms of the production of milk, butterfat, meat, wool, and other dairy and sheep products. “We are endeavouring to correlate methods both in the field, in pots and by chemical and biological methods, in our work at the Soil Fertility Station. In time we hope to make these methods, especially the chemical ones, available as a service to farmers to assess their soil fertility through the agency of the local instructors in agriculture. This can only be done by using simple and rapid tests such as can be used on the farm or in the office, and to develop these tests has been the aim in the establishing of a travelling caravan laboratory. “In the near future we hope that all instructors will be issued with testing kits, but you must not hope too much for them. They can give you fairly reliable information about your soil acidity and need for liming, about the nitrogen status in crops and about the available potash in your soils and pastures. “When it comes to phosphate, the same old difficulty always crops up. The plants, and particularly the clovers, can abstract from soils, phosphates which are locked up in various forms of different relative availabilities and which no methods so far devised of a chemical or even of a pot culture nature, seem quite adequately to reproduce. The main methods are under trial, and some of them at least, are giving promise. “Your local instructor in agriculture is a general practitioner ' who can best diagnose any difficulty on your farm. He knows the soil type and conditions intimately, and is more of a specialist in his own area for the general run of farm difficulties and teething trouble than the specialist who deals with long range problems of research.”