DOMINION GRASSLAND

Waikato Times, Volume 121, Issue 20269, 11 August 1937, Page 9

DOMINION GRASSLAND

FACTORS IN FERTILITY. [ ADDRESS BY MR. A. H. COCKAYNE. (Special to Times.) DUNEDIN, Tuesday. The importance of grassland In the national economy of New Zealand was emphasised by Mr. A. H. Cockayne, J Director-General of Agriculture, in his . presidential addre-ss to the annual conference of the New Zealand Grassland Association this evening. Thirtytwo million acres produced the Dominion’s grass crop, compared with 1,500,000 acres devoted to other crops, he said; and from the gTeen herbage produced came the butter and cheese, the meat and wool which represented the country’s livelihood. “If wool is excluded from these items,’’ said Mr Cockayne, “we are left with dairy and meat products, which are dependent on the one hand on the cow and on the other on the ewe. The point I wish to make Is that in New Zealand grassland farming it is the female animal which is the index which must be used to measure production, and it Is on an increase in our female livestock that expansion in production comes about.” It was essential, he went on, that female livestock —cows, ewes or sow-8 —should be fed with nourishing food of a milk-producing character; and for that reason it followed that New Zealand grasses should be primarily of a milk-producing type. The actual age of the herbage was the essential feature determining whether a pasture was milk-producing. Vigorously growing or fresh young herbage was suitable for milk production, while old or mature grass was not. “The whole objective of grassland farming In New Zealand,” said Mr Cockayne, “Is to maintain pasture In a young, vigorously growing condition for as long* a period of the year as possible; in other words, to develop conditions and management so that the pasture remains permanently juvenile." Three Factors Involved. The ability o? a pasture to remain permanently Juvenile was influenced by three great factors, the speaker continued, all being capable of skilful manipulation by the farmer. The flrst might be termed the fertility of the soli, for want of a more deflnte description. The second was the type of herbage, and the third was its ability to reoover speedily when pruned. The latter factor was conditioned by fertility and the type of plant being pruned. The real, practical essence of a pasture remaining young or becoming old depended on its ability to produce fresh growth after being pruned, or, to use the farming term, its ability to recover after grazing. In arable districts the common method was to let pastures beoome old within a few' years. When this condition arose the.laud was cropped for a season or so and the pasture then renewed. It remained young for a year or so, and the process was repeated. This method worked well In arable districts, but was expensive. One of the most important methods of developing fresh supplies of young grass was to prune or eat out the growth and rely on the immediate fresh growth response. A whole range of grassland farming practices, with the object of developing fresh growth after rapid pruning, had been developed. The orudest form was exemplified by the burning of tussook grassland, and the mowing or topping of dairy pastures oame into the same category, though the latter was often necessary, whereas the former should be avoided except in certain typos of seoond-growth pasture. The whole theory of subdivision of grassland was connected with the pruning theory of young grass production, as It enabled manipulation In stock oonoentratlon to be adopted by the farmer. Top-dressing with Fertilisers. “It 1-s the extent of the vigour of growth, ooupled with the type of herbage, that largely determines the rapidity and amount of response that . takes place after the grass is fed off, and, in general, such vigour is in direct relationship to fertility,” Mr Cockayne continued. It appeared that the greatest single applied factor generally increasing the vigour of growth on most pastures was topdressing with pbosphatio fertilisers. At any rate, wherever there was a distinct clover response to top-dress-ing such represented the easiest way In which increased vigour could come about. The outstanding feature of the 1 last decade and a half of top-dressing had been the fact that, irrespective of tho initial fertility of the soil, pastures of very high production permanently producing young, vigorous herbage had been developed, this leading to the formulation of the surface fertility , theory of permanent young grass. “Veneer of Fertility.” When top-dressing was carried out on soils whose surface fertility was 5 low a mulch of nutrient material was

provided Just below ground level, Into which new roots penetrated at an early stage of growth, and It appeared that when a rich surface layer was provided. If drainage were adequate, permanent high productive pasture of milk-producing character oould be developed. “It would appear,’* «ald the speaker, “that the essential for vigorous permanent young growth Is a veneer of fertility Just at ground level, and In most cases this veneer can be provided by phosphatlo top-dressing, where there Is an adequate rainfall and provided a clover response is brought about. ... It would appear, therefore, that the theory of surface fertility for permanent milk-produoing pastures is a sound one." Summarising his remarks, Mr Cockayne said that New Zealand's grassland products were dependent on the adequate feeding of female livestock; the latter were dependent on adequate supplies of young, vigorously growing herbage, “wet stook pasture,” maintained as such. Under a permanent pasture system these supplier -were dependent on renewal following pruning; efficient pruning was dependent on the control of stock concentration, whioh in turn was dependent on the maintenance or Improvement of surface fertility of grassland, and provided the cycle was not broken, permanent wet stock country resulted.