ROTATIONAL GRAZING

Manawatu Standard, Volume XLVIII, Issue 229, 25 August 1928, Page 8

ROTATIONAL GRAZING

IMPORTANT LINE OF RESEARCH. INCREASING BUTTER-FAT PRODUCTION. TRIALS BEING CARRIED OUT. For ages past it has been recognised by farmers that vigorously growing young grass represent the ideal feed for milk production and young stock. The farmer did not particularly bother about the reasons. why young leafy herbage possessed all the qualities making it ideal for milk production and growing stock, while more mature herbage with its large proportion of fibrous stems was unsuitable. The fact that experience had shown such to be the case was good enough for him. During recent years, however, a tremendous impetus has been given to the question of the production and, more particularly, the efficient manipulation and utilisation of young rapid loaFproducing pasture, primarily through experimental work begun some ten years ago at Hohenheim on the Continent of Europe. There it lias been shown that butterfat production per acre could bo enormously increased by the stimulation of grass growth and by its extremely rapid feeding down whenever the herbage was between three and five inches in height, the whole principle involved being the avoidance of the grassland ever “getting away,” as is customary where what has been termed “rotational grazing” is not adopted. In rotational grazing grass production is viewed as the production of an actual crop that has, like any other crop, to bo harvested at that period when it is most economically sound to do so. In the case of annually sown crops tliero is, however, generally only one harvesting period during the year. In the case of rotationally grazed grassland, harvesting has to take place whenever the growth has reached the requisite height, say four to six inches, in the case of dairy stock; and considerably less where sheep are used as the harvesting implement. The periods alternating with grazing or stock harvesting under rotational grazing are to be viewed as definite crop-growing ones, during which no stock are pastured on the paddocks. NITROGENOUS TOP-DRESSING. In addition to the value of rotational grazing, the work at Hohenheim attracted a great deal of attention as it was shown that periodically top-dressing with nitrogen in some form, in addition to liberal applications of phosphates greatly lengthened the period during which abundant leafy young _ growth was produced, besides increasing the total amount that could be rotationally grazed. In point of fact the result of the work at Hohenheim has directed attention rather more to the stimulating effect of nitrogenous top:dressing on grass production than it has to the enormous significance of actual young grass production and its efficient utilisation.

A second factor that has been of outstanding importance in focussing attention to the fact that grassland management is essentially concerned in the production and utilisation of young grass has been the work of Professor Woodman, of Cambridge University, in emphasising the actual nutritive value of young leafy grass against more matured herbage. He lias shown that what for ages has by the farmer been termed “young sweet feed” has a feeding value for milk production at least double of that when the same grass is allowed to become old—in other words, grass that “gets away” is only half as valuable, so far as the dry matter contained is' concerned, as it would be if consumed in the young four to six-inch stage. RESEARCH IN NEW ZEALAND. During the past two years the question of rotational grazing and special stimulation of young grass growth b v periodical applications of nitrogen in addition to phosphates has been under investigation on a large number of farms in Great Britain. This work has been particularly taken up by the Imperial Chemical Industries, a powerful organisation that, apart from its commercial activities, is developing extensive crop and grassland research work in many parts of the Enipire. This organisation has recognised that New Zealand, with its advancing development in grassland farming offered a splendid field for an intensive study of what is now becoming popularly termed “the modern system of grassland farming,” but which in point of fact is as old as the tethering system of the European peasant, and, in reality, simpiv represents the best possible use being made of grass when at its most nutritive stage. Accordingly, Imperial Chemical Industries recently offered the Department of Scientific and Industrial Research to place both monetary and other facilities at its disposal to assist in a thorough study, to determine the value of nitrogen combined with rotational grazing on the various grassland types in New Zealand. This work is under the control of Mr A. H. Cockayne, Director of the Fields Division and Plant Research Station, and a start has already been made this season, although, unfortunately, arrangements wero not finalised sufficiently early this year to attempt more than certain preliminary work. In the Auckland, Taranaki, and Wellington districts, trials are being carried out on nearly one hundred farms, of which nine are in the vicinity of Palmerston North. On each farm two paddocks of similar type and size have been selected, and both paddocks have the same ’dressing of phosphate, while one, in addition, has been topdressed wiith 1 cwt. of sulphate of ammonia, which was applied during the month of July. It is intended to rotationallv graze each area carefully during the season, making, where deemed advisable, periodical applications of nitrogen to the mtrogened paddock. It is hoped that this season’s work will give a great deal of valuablo information, and that from the experience' gained more comprehensive trials will be instituted in the coming autumn. MOST IMPORTANT WORK.

In conversation with a "Standard” representative. Mr Cockayne stated that this work, on what may be termed specialised top-dressing and rotational grazing, gave promise of being the most important undertaken by his division along the line of grassland management, and should yield results that when practically applied should have very far-reaching effects so far as production was concerned. ‘•‘lt is fortunate,” ho said, “that Imperial Chemical Industries have seconded to the Plant Research Station the services of Mr R. Lindsay Robb, their chief grassland expert. His assistance will be invaluable as li© has had control of the whole of the experimental work being carried out in Great Britain. He returns to England about the end of November, but will be back again in time to supervise our next year’s programme, which will commence this coming autumn. From preliminary observation I have made it would appear as if there was clearly an important place for nitrogen in dairy grassland management to

supplement the even phenomenal results that have followed national topdressing with phosphates. Valuable as these are, they are weak in the production of specially early spring grass and likewise in sufficiently stimulating late autumn growth so that a good amount of feed may be aavilablo in the winter. Nitrogen clearly appears capable of considerably lengthening the dairy season—the allimportant question that lias to be determined is whether it will do so on a profitable basis. Quite apart, however, from whether nitrogen topdressing should bo a feature in management by the progressive grassland farmer, the work being undertaken in co-operation with Imperial Chemical Industries should provide the experience necessary to place practical system of rotational grazing on a proper basis in New Zealand. Plenty of young grass consumed as such is the all-essential in high butterfat production per acre, and improvement in the utilisation of young grass is certaintly intimately associated with successful rotational grazing practice. “There are, however, many technical difficulti&s in the management of rotationallv grazed farms, but the prospective huge returns that may be expected from them when these difficulties have been smoothed down warrant the fullest investigation into all phases of rotational management.”