PASTURE FOR SHEEP

New Zealand Herald, Volume LXX, Issue 21548, 20 July 1933, Page 18

PASTURE FOR SHEEP

SECONDARY GROWTH CONSOLIDATION ESSENTIAL

nv H.B.T,

At a recent conference, of sheepfarihers licit] at the Mnssey Agricultnrnl College, Mr. Bruce Levy secured a number of interesting photographs illustrating the results, in reversion to secondary growth, of different methods of grazing. On one sido of a fence one saw apparently well-grassed country with no growth of scrub, fern or biclibirli and on the other, these plagues of tho back country sheep-fanner well established and threatening shortly to ruin the land. The well-grassed clean country, Mr. Levy stated, was crazed heavily with cattle, while that showing considerable secondary growth had been grazed almost exclusively with sheep. The conclusion was that by close grazing the sheep killed out many of th<v better permanent grasses and so thinned the sward that bare spaces were left where weeds, fern and scrub became established. On tho other hand, the cattle being not nearly such close grazers as sheep, did not kill out the grasses; no bare patches resulted, and consequently no secondary growth became established. On this hypothesis, Mr. Levy recommended that pastures on light hill country should not be grazed too closely with sheep and the farmer would not be troubled by secondary growth. Another Explanation My own experience and observation does not wholly support Mr. Levy's conclusions, and as tho reversion ot grassed hill country to these secondary growths is such a serious matter to our back country farmers, 1 feel it might serve a useful purpose to offer another explanation of why these adjoining areas, differently grazed, produced such vastly different swards, i In the first place 1 have yet to see ' any permanent grasses adapted to the I soil and locality, killed out by close ' once they have been allowed i to become established. On badly or I lightly-grazed areas I have seen the | stronger-growing varieties _ of grass j smother and kill out tho finer species I and so, at certain seasons of the year i leave bare patches where weeds may establish. But where each plant receives its share of sunlight and air, as with close grazing, plants do not die from this cause. 1 believe the cause of the obvious difference resulting from grazing with cattle is that these heavier animals consolidate tho surface soil and so encourage permanency. Every farmer will have observed that on sunny faces, even on light ' ai jd, where the stock are constantly grazing closely and consequently consolidating the surface, very little secondary growth can be seen. Over the hill, on tho face lying, away from the sun, where the grass is long and few animals graze, scrub fern and bidi-bicn can be seen on all sides. Fence this shady face off so that the stock, par- | ticularly heavy stock like cattle, must i graze and consolidate it, and encroach- ; ment of secondary growth and weeds I is immediately arrested. Further, if I these shady faces are thoroughly conS solidated by heavy and close grazing, i no secondary growth will reappear in i the future. Again one can see the effect of consolidation along ridges and hilli tops where stock normally travel and I camp. On these localities, however I closely the grass may be grazed* it i persists and resists tho intrusion of i secondary growth. Supply o 1 Moisture j Surface consolidation by heavy stock ! encourages the flow of subsoil moisture |to the surface where shallow-rooted | grasses can avail themselves of it. Where the surface soil is not compacted by heavy trampling, the grass plants die for want of moisture, and as nature insists that, whore possible, tho soil must support some form of vegetation, deep-rooted ferns, weeds and shrubs become established. I remember a notable example of the effect of consolidating light land which may servo to prove that it is of infinitely more importance than the method of "grazing. _ A friend had, in one corner of his property, a very light paddock of 'fluffy pumice formation. He worked it up in the orthodox manner and sowed it down with a mixture in which perennial ryegrass predominated. As a consequence of heavy top-dressing and a favourable season tho farmer was able to cut a heavy crop of early hav, after which the paddock was grazed regularly. Two years later I saw this paddock again, and the only grass which then remained was in the wheel tracks of the dray which had been used to cart the first crop off. Here the ryegrass throve luxuriantly in strips four inches wide while the rest of the paddock contained weeds or was bare. The subsequent history of the paddock was interesting, for the farmer convinced that surface consolidation was essential disced it up and sowed red clover. This, an excellent crop was made into ensilage and fed out in tho same paddock to young cattle, the land being harrowed each autumn and a ryegrass and white-clover mixture broadcasted to be later heavily trampled by the stock. This paddock is now one of the best permanent pastures on the farm, and is continuously close-grazed with sheep without any sign of invasion by weed or other obnoxious growth. Example on Limestone Country A further instance of the effect of consolidation by cattlo comes to mind. A farmer who owned light limestone country of tho gritty type, some years ago found himself with a big draft of station cattle on hand. These he was forced to hold under very hard conditions for two years among the sheep before he could quit them at a reasonable figure. Naturally tho area was very closely grazed and heavily trampled; but six months after tho cattlo had been sold this farm stood out from its neighbours as tho best-grassed with English grasses in tho district, and still maintains that position although not an ounce of seed was sown to effect this improvement. T could record many more instances which have come under my own notice, did I think them necessary to prove that the incursion of secondary growth was not influenced to any appreciable extent by close or light grazing. We, however, arrive on common ground with Mr. Levy in stressing the absolute necessity for cattle in establishing permanent pasture of the' better-type grasses, and for preventing the incursion of weeds and secondary growth. Once, however, the surface soil is consolidated by these heavy animals, their continued grazing for this purpose is not essential, and , close-grazing by sheep will, 1 am convinced, not damage tho sward.