THE GRASSLANDS OF NEW ZEALAND.

New Zealand Journal of Agriculture, Volume XXXVII, Issue 4, 20 October 1928, Page 229

THE GRASSLANDS OF NEW ZEALAND.

GRASSES AND CLOVERS FOR HILL COUNTRY — continued.

E. Bruce Levy,

Agrostologist, Plant Research Station, Palmerston .North.

(8) Ratstail (Sporobolus indicus).

During the past few years many species of grasses and clovers have been reviewed and carefully weighed in the light of the newer conception — that conditions of soil-fertility, soil-moisture,: light and shade, climate, and management govern which species are the most profitable for the farmer to use. There is the rye-grass habitat or growing-place, the cocksfoot habitat, the brown-top habitat, and the danthonia habitat, already dealt with in this series. No grass perhaps has been more difficult to allocate to its proper place in the ecologic classification of species and to get accepted by pastoralists and agricultural advisers than ratstail. . .

Moderately warm climatic conditions, low-fertility soils usually of a loose friable nature such as sand, pumice, and limestone, characterize the ratstail habitat. This grass will grow and persist on soils poorer in quality and more difficult even than those where Danthonia pilosa thrives. It falls more naturally, so far as its growing-place is concerned, along, with low-production grasses such as bay-grass (Eragrostis Brownii),. Grimmer grass (Triodia decumbens), and - Danthonia semiannularis, although there is no doubt that , on sufficiently warm areas ratstail can compete successfully against Danthonia pilosa, particularly when allowed to away rank. (Fig. 137.) Omcertain hydraulic-limestone country in North Auckland where the physical conditions of the soil are difficult to maintain right for cocksfoot, &c., ratstail has spread and has formed a tall dense growth that entirely prohibits the establishment or spread of low-growing grasses and clovers. Under ungrazed conditions, therefore, owing largely to its tallness of growth, ratstail. may assume complete dominance and completely master danthonia and other lowproductive, low-growing species. (Fig. 138.)

In growth-form ratstail is a tussock ; the crown is below ground, and spread is by means of short underground tillers and from seed shed. The root-system is extensive, and the larger roots penetrate 2 ft. or more into the subsoil. The grass is held in low repute by many farmers, largely on account of the toughness of its rather broad, erect leaves. Ratstail is a native of Chili and “ according to the late Bishop Williams made its first appearance at the Bay of Islands in 1840, shortly after , the arrival of a ship called the Surabayo, which, while on a voyage from Valparaiso to Sydney laden with horses and forage, put into the Bay of Islands in a disabled state and was there condemned and her cargo sold.”* - '

Ratstail has not the wide distribution over New Zealand that Danthonia pilosa has. It will not tolerate extreme cold, and its climatic range coincides somewhat with that of paspalum, although its adaptability to poorer soil-conditions would make it appear much more tolerant of cold than the latter grass. In North Auckland large areas of ratstail

have been cleared by late autumn or winter burning, thus exposing the crown and any fresh growth to frost. (Fig. 139.) The grass, however, thrives quite well along the entire coastal country of the North Island, and inland to as far south as the Wanganui River, and possibly farther. In the South Island it is confined largely to the coast of the northern, end of the Island on the east, but extends farther south on the west. These climatic bounds, however, may not represent the extreme ultimate limits for ratstail in New Zealand. Within the colder areas we know that spread from seed shed is extremely slow, and as comparatively little seed of this species has ever been intentionally sown within

these areas there is little chance afforded of knowing without definite experimental work just what the ultimate climatic range may be.

There is no doubt that for the general dry hard-conditioned soiltype throughout New Zealand the grass that has the widest application throughout the entire range of such lands is Danthonia pilosa ; " but for special warm country, particularly coastal, throughout both Islands, the native danthonia has a big rival in the alien ratstail.

It is almost inconceivable that the New Zealand danthonia soil-type has not its counterpart in other parts of the world. Such will be grassed by species akin to danthonia in 'demand of soil-fertility requirement,

soil-moisture, light and shade, &c., and when these are introduced into the danthonia habitat here the struggle with our like - demanding species is apt to be keen, and generally speaking the taller grower will survive. It would appear, therefore, that throughout much coastal country, in the North. Island particularly, ratstail will gradually assume dominance over danthonia, especially so under light grazing. Under close and continuous grazing which permits plenty of light to the danthonia crown, and which somewhat prejudicially affects the tussocky ratstail, the odds are essentially more equal, and ratstail and danthonia may blend one with the other, making a close and continuous turf. (Fig. 140.) ' ' VALUE OF RATSTAIL. : Ratstail has some very strong supporters, and among , these are men of high standing in pastoral New Zealand. .Mr. H. Guthrie-Smith and Mr. Bernard Chambers (Hawke's Bay) may be mentioned as the foremost advocates of this grass. Mr. Chambers writes : — I consider ratstail has no superior on certain soils ; the. Kiwi Valley, on the Wairoa Road on Waihua Run, used to be barren useless land covered with stunted manuka a foot or so high. The spreading of ratstail and danthonia has made it one of the finest pastures I know. On the light pumice spurs also of Kiwi Station, where other grasses died out, ratstail formed a beautiful close sward. If kept in order by cattle, it is always grazed close by sheep, and the blades are sweet like those of prairie-grass ; weedy hoggets following thrive, wonderfully on the grass and do not scour. I know land north of Gisborne that has been made by ratstail in the grass-seed mixture. On the Havelock North hills in spring-time, directly they begin to burn up) both sheep and cattle neglect danthonia and graze each tuft of ratstail close. . ... At Mokau, Mohakatino, and our Mangtoi Station leasehold, twenty miles up the Mokau River, ratstail stands ahead of all other species , on spurs which grew only, tawhero (kamahi) and rewarewa, a sure sign of poor light soil. On them cocksfoot, rye-grass, and every other grass died out and gave way to catsear and suchlike rubbish.. On those spurs wherever ratstail has got in it has made a beautiful closely-cropped sward.

In a recent communication from Mr. Guthrie-Smith regarding the merits of ratstail for the so-called Hawke’s Bay pumice-lands he says : —

Over areas I am describing there is a normal surface of four or five inches of dark dusty humus, then a sheet of four or . five inches of grit, then deeper down either a poorish clay or a deposit of packed water-laid reddish sand ; this last contains evidently at least a whiff of clay, as it becomes hinu and greasy when wet. For such soils a deep-rooting grass is pre-eminently required. It is supplied by ratstail, which has a root-system exceeding, I should imagine, that of any other pasture-grass in New Zealand. Ratstail in this type of land is able to assimilate any virtues which may exist in the top dusty dark' humus, penetrating which it then pierces the pumice land, and is then still able to search for nutriment a good foot into the clays and greasy, sand-grits beneath. No wonder we think highly of it ; no wonder it can grow on wretched utterly infertile (surface infertile) northern and western-facing knee and elbow knobs. In such miserable areas—cited purposely because extreme cases of poverty — has a genuine feedingvalue. On normal pumice areas this feeding-value, of course, greatly increases. On lands not properly worked, where mixed danthonia and ratsta.il grow, everywhere it is my experience that ratstail is bitten close while danthonia stands untouched. Quite good as the latter may be as a poor-country grass, ratstail beats it out of the field because of its enormously developed root-system. Danthonia cannot feed as deep, and therefore cannot reach sources of nourishment open to a rival that can penetrate twenty-four inches into the subsoil. Although not a cold-country plant, this root penetration enables it to maintain a considerable growth even in the winter ; throughout the cold months fresh leaves can always be found rising stiff and stark from the hard uninviting mate On the tens of thousands of acres of light hill country in northern Hawke's Bay facing north and west—lands hopeless for any other crops than trees— ratstail is the only grass that will provide feed,for sheep, and especially • (relatively) winter feed; if ever there

was a poor man’s grass it is ratstail. So -much. for pumice areas. On sound limestone lands where after forty years of feeding the better English grasses and clovers have disappeared ratstail is equally valuable, mot only in itself but also from its habit of growth. It grows, even where thick, not quite densely enough entirely to-exclude such another invaluable alien as suckling clover. When ratstail shall have spread over my limestone lands they will, I am confident, carry another quarter-sheep per. acre. On. bad lands, . therefore, as also on the excellent fertile limestone of mid Hawke’s Bay, ratstail stands forth as a valuable pasture-plant. - *' ■ . , ,

It is not for me or any one else in New Zealand to gainsay the opinions of these men, for such opinions are based on the practical experience of a long lifetime, and come from a stock of wonderful general and specific knowledge of practically all pasture plants with which ratstail may be compared.

Ratstail pastures do. not gain credit from their appearance. When at all long the- pasture looks rough, and at all .times lacks that nice green and even appearance characteristic . of the regular turf-forming grasses, Even when closely grazed the tussocks - appear somewhat raised, and the short stiff, leaves present a bristle-brush appearance. It is generally heldand is true — ratstail is hard on the mouth of sheep, and this has often been put up as an argument against the value of the . grass. ’’ It must be borne, in mind, however, that hill country where we recommend ratstail is not aged-sheep country under any turf whatever. In the words of Mr. Guthrie-Smith himself, “ What flockmaster nowadays desires to keep his sheep as records in longevity ? ” Even if the teeth are somewhat worn and rather belie the animal's age, any practical man when sheep from ratstail country are exposed for sale understands the position, and , the fact will scarcely affect his bid.

POINTS IN MANAGEMENT.

The men whose experiences have been cited are large holders and are well equipped with; cattle. Perhaps no grass demands stricter attention by “ cattleing ” than does ratstail. The ill repute in which it is held by many farmers may be . attributed largely to the fact that in such cases few or no cattle were available to render it suitable forage for sheep. Ratstail • management is distinctly correlated with plenty of cattle, and without this, all-important implement ratstail may prove a curse rather than a blessing. This, however, to quote Mr. GuthrieSmith, “ is not the fault of the grass, but of . the landowner who does not understand his business ; it is a species that must be cattled, just as danthonia or cocksfoot or any other pasture must be cattled, to give best results.” ' - . .

There is no doubt that young ratstail growth is highly nutritious ; all classes of stockhorses, cattle, and sheep — remarkably well on it. , It has been said that .horses grazing on ratstail thrive equally well as oaten-chaff-fed horses ; but it is equally true that grazing horses feed largely on extremely short herbage. This emphasizes the need of keeping ratstail short. ,

An aspect of ratstail that also , is a recommendation is that the grass forms a reliable standby in a lean period. Whereas all pastoralists will agree that young growth is the most nutritious, and the exploitation of young growth is the crux of pasture-utilization for maximum value per given weight of herbage consumed, yet on virtually all the poorer hillcountry runs the factor of rough growth to tide over crucial summer and

winter periods of shortage is equally important as that of well-cropped, short, young growth. Ratstail may essentially be relied on to provide this rough growth. Owing to the tough nature of its leaf it matures in situ as rough feed and does not lodge. Thus there is provided food of a sort that ‘will at least sustain stock during a summer drought or through a severe winter. (Fig. 141.) . ’ ■

SIGNIFICANCE OF RATSTAIL DOMINANCE ON BETTER-QUALITY SOILS.

Ratstail on certain soils is capable of tall growth '(Fig. 142), and in the absence of cattle it may assume control of country that would normally carry good danthonia, some Poa pratensis, crested dogstail, and a’ trace of cocksfoot and rye-grass —a turf which may be fairly easily managed with comparatively few cattle. This aspect of ratstail, particularly for the small landholder, must be carefully considered. I am not so sure with Mr. Guthrie-Smith that ratstail is a poor man’s grass. Ease of management is essential for the small farmer, and the securing of this often more than compensates for any loss incurred through not using a higher producer that is difficult to manage —nay, almost impossible to manage without the expensive implement, cattle.’ In North Auckland this is strikingly, well illustrated in the case of paspalum, and also in regard to ratstail on certain hydraulic limestone country about .Paparoa.. (Fig. 143.) This country is heavy, wet, and cold, and the physical conditions seem to render it unsuitable for thriving of the better grasses; yet it suits ratstail to perfection. On country such as this, burning and surface sowing of red and white clover, together with manurial top-dressing, often results in the entire elimination of ratstail. It is really a soil-type that should not be carrying ratstail, being wet enough to render available any phosphate manure . that .may be applied. .Ratstail cannot compete successfully against a stronggrowing turf of the first-class English grasses and clovers, and- even moderately-well-growing brown-top and Lotus major prove more than a match for ratstail. (Fig. 144.) On country, therefore, that is wet enough to render artificial manures readily available, just as the manuring out of danthonia and brown-top is advocated, so here ratstail should not be tolerated, and its elimination from such country, as shown in Figs. 142 and 143, should be the aim of the farmer. Even where the ratstail is not quite eliminated the presence of clovers induced by the manuring renders the ratstail pasture of much greater value. (Fig. 145.) On country that can be heavily tripod-harrowed in conjunction with manuring the process of eliminating ratstail is made easier. The tussock of ratstail is torn by the harrow, and, provided the soil-fertility is built up enough, species such as brown-top, Lotus major, white clover, &c., readily penetrate the broken crown and thus help to smother the ratstail out all the quicker. Some very good examples of ratstail-control by manuring and harrowing may be seen on the main Awakino Valley Road, where paddocks only lightly stocked, unharrowed, and unmanured may run dominantly -to ratstail, while adjoining paddocks well farmed are comparatively free of this grass. It . is on the unploughable, unmanurable hill country-land . that ■has been under beech forest (where the climate is warm enough), poor kamahi, rewarewa, tanekaha, and hinau spurs, &c., poor light soils, fluffy soils, pumice sandhills, and coastal scrub country —that ' ratstail undoubtedly has a place.

SOWING OF RATSTAIL.

The fine reddish seeds of ratstail are extremely slow to germinate under average field conditions in New Zealand, and even under artificial conditions in the seed-testing laboratory high germination tests are never secured. Where germination has' taken place establishment is extremely slow. In 'experimental sowings made in Taranaki three and four years ago, only a few plants are now visible in the turf. On warmer country, however, establishment is more rapid. On the lighter fluffy soils, owing to the tough nature of the herbage, loss of plants through stock-pulling is often high. The principle of sowing only small amounts of seed of extremely slow establishers is adhered to in the case of ratstail; 4 lb. to i lb. of seed per acre included in the mixture affords establishment of a few plants, and reliance is then placed on these reseeding and in the course of time filling up and thickening the turf through shed seed.

Ratstail seed is often difficult to secure, merchants to a very large extent having ceased to handle it, owing largely to depreciatory propaganda mitigating against the demand. It seems to be very desirable that merchants operating over country such as here specified should carry stocks of ratstail-seed and recommend it for the special soil-type and conditions appertaining to the poor hill and coastal country of both Islands. Ability of the holder to manage his country right should, however, he expressly taken into consideration.

CONCLUSION.

There is no doubt that ratstail has a place on the soil - types here defined, and the recommendation of practical men such as Mr. Guthrie-Smith, Mr. Bernard Chambers, and others should go far to allay the general unwarranted condemnation that is abroad in the minds of pastoralists, seed-merchants, and agricultural advisers in general.

(Series to be continued.)

* “ Tutira, the Story of a New Zealand Sheep Station,’.’.p, 179 ; by H. Guthrie-Smith.