Art. LXI.—The Farm: Winter Pasture and its Grazing.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 24, 1891, Page 628

Art. LXI.—The Farm: Winter Pasture and its Grazing. By J. R. Wilkinson, M.A. [Read before the Philosophical Institute of Canterbury, 4th November, 1891.] It is a common opinion among Canterbury farmers that there are annually two seasons of no growth of grass on the plains —the first during summer drought, and the second during the severity of winter. These two seasons of no growth are usually well defined, and it goes without doubt that there is no growth in the summer when every tuft of grass is seen to be parched dry; but with respect to the winter season the evidence of no growth is scarcely sufficient, and to make a test I measured regularly during the winter of 1890 the blades on selected shoots of rye-grass and cocksfoot, with the result that, so far as that locality—Richmond, Christchurch—was concerned, there was a continual growth throughout June, July, and August. Measurements were made twice a week, which showed that the minimum rate of growth was during open weather—sunny by day and frosty at night—while a shower of rain always produced comparatively a burst of growth. It was also seen from the totals that the growth during August was as great as that during June and July together, a result hinting that not nature but our system of grazing is at fault when we find, as is so often the case, our sheep-feed scarcer in August than in June or July—a point that will be referred to again. During the past winter I again took careful and regular measurements every two days of the blades on selected shoots, and plotted the curves of growth on a chart, again showing growth to be continuous but irregular. The observations made this year at Addington were more extensive than last year's, the shoots measured comprising one of rye-grass and one of cocksfoot allowed to grow naturally, and one of rye-grass and one of cocksfoot kept clipped short, at about ¼in. average of blades. The clipped tufts were taken to represent the state of our pastures under our prevalent system of close grazing, and the unclipped tufts to represent pastures not stocked during June, July, and August. It has seemed to me for a good many years that the ordinary system of close grazing secures a minimum yield of grass. Through extensive periods, twice a year, the cry of scarcity of feed is heard in two-thirds of the plains, and an inspection of the pastures of these times shows that the shoots have been eaten to the core, and each plant has become a hard knob, devoid of power of growth and

reminding one of an over-pruned tree or of a hedge too often clipped. A comparison of the growth made by the unclipped tufts with that of the clipped ones shows that the unclipped produced very much more than the clipped. Taking first the rye-grass, I found that during June the unclipped grew three and a half times as much as the clipped, during July two and two-thirds times, and during August four times as much, the rapid spring growth of the latter half of August having had much greater rate of effect on the unclipped than upon the clipped. I may say that during the recent winter the total growth of the clipped shoot was 4 ½in. in the three months—June, July, and August—and the total growth of the unclipped in the same time was 12 11/12in.—say, 13in.—or nearly three times as much as the other. With regard to the cocksfoot the results are different, for the reason that the clipped tuft was a very healthy plant, while the unclipped one was not very vigorous until the latter half of August. During June the tables were turned, and the clipped grew 13/12in., while the unclipped grew only 5/12in. During July the clipped grew 2 7/12in., and the unclipped ascended to 2 7/12in.; and during August the superiority of the unclipped over the close-grazed was well shown by 7 5/12in. to 2 8/12in.— not quite three times as much. The general result is, therefore, that pasture unstocked during the winter produces nearly three times as much feed as equally healthy pasture grazed close. Very noticeable, too, is the narrow width—much narrower than the normal—of the blades of the clipped tufts; and also, in all probability, the damage done to the tuft by the sheep's teeth would still further diminish the yield. Now, turning to the practical side, we find a factor coming in to interfere very greatly. At the middle of July the old blades began to frost off at the ends, the younger blades not being touched by the frost; and this withering of the old blades went steadily on until the end of August, so that it might almost be said that as fast as the young blade grew the old one died off, and, indeed, at the middle of August there was less feed on the unclipped rye than on the first of the month, on account of rapid withering. The clipped tufts showed no sign of being frost-bitten: and now, comparing the available sheep-feed instead of the total growth, we find that the clipped rye produced 4 ½in., while the unclipped produced 5 ½in., or 22 per cent more; and that the clipped cocksfoot produced 6 1/12in., while the unclipped grew 8 6/12in., or 40 per cent. more. It does not seem, therefore, that a vast gain will be derived from keeping the pastures unstocked all winter, but rather that, judging from last winter, the fields should be un-

stocked during June, grazed down during the first half of July to secure the feed that would otherwise be frosted, and again unstocked till the middle of August, or later, every day at this period producing three times as much growth as a day in July. Such a method of winter feeding will, of course, necessitate some large fenced-off yards and plenty of artificial food; but it will secure a fairly maximum yield from pasture, and I see no theoretical objection to it save one. It appeared that a shoot of grass grows only at its youngest blade, the second youngest growing very slowly indeed, and the others not at all, so soon as a new blade appears and begins, as it does, to rush ahead. It may be, therefore, that a mature blade gives up its nutritive substance more or less to the youngest blade; so that when it is liable to be frosted it has already become of poor value as feed, and its loss is not of much consequence. Should this surmise prove correct it seems to me that to keep pastures wholly unstocked during winter is a necessity for sound scientific grazing. Should the surmise prove incorrect it would be sound policy to graze the pastures to a considerable extent once in the winter—that is to say, at the commencement of the frosting of the old blades. In conclusion, I find by inquiry the opinion is very common that grass grows from the root rather than from the blade; and, of course, such an opinion is in accord with bare grazing. On the other hand, the botanist asserts that grass grows from the blade rather than from the root, and he considers, therefore, that bare grazing is thoroughly unscientific and unprofitable. Postscript.—Since this paper was read I have noticed that the clipped tuft of rye-grass had its vitality so impaired by the clipping that it was unable to stand the slight drought of early summer, and almost completely died out.