GRASSING EXPERIMENTS ON HILL COUNTRY IN WHANGAMOMONA COUNTY.

New Zealand Journal of Agriculture, Volume 43, Issue 4, 20 October 1931, Page 241

GRASSING EXPERIMENTS ON HILL COUNTRY IN WHANGAMOMONA COUNTY.

E. Bruce Levy,

Agrostologist, Plant Research Station, Department of Agriculture,

Palmerston North.

Introduction.

In this Journal for March and June, 1927, the progress of regrassing experiments on secondary-growth country was given in some detail, and these articles should be again consulted and studied by those interested in conj unction with the following additional experiences on these areas daring the subsequent four years. The main experimental sowings have now been going for seven years, and this time may be regarded as sufficiently long to enable very reliable data to be secured as an outcome of the seed .mixtures, sown , under the varying conditions of farm management these have ' been subjected to. Let it be said at the offset no seed mixture in itself, can be devised to grass primary-forest and secondary country without vigilant and specialized farm management.

The question of fences, class of secondary growth being tackled, when to burn, when to sow, when to stock, class of stock, how to stock, and how best to maintain soil fertility, all come in for consideration. Hill-country farming on primary- and secondary-growth country is intimately bound up in shepherding the country rather than in shepherding the stock. Literally, much hill country has to be hammered into grass with often little regard to the well-being of the stock . engaged. The grass-seed mixture sown and the manuring of the sward secured will very largely determine just how hard- the stock are to be punished in order to control the secondary growth that comes away after the fire. To .my mind there is nothing worse than the forcing of ’stock on to dense secondary growth without first making an endeavour to get some grass to support the animals in . their work of crushing. I know full well this is a criticism of a practice that has been used in the past and is advocated still by many large runholders; but, in my opinion, much good country brought in in this way that is now carrying danthonia, sweet vernal, Yorkshire fog, and catsear dominant should be carrying very much better species of grasses and clovers.

In. the Journal for June, 1927, were detailed some eight methods of breaking in secondary - growth country. Continued observations during the four years since that article was written have tended to confirm the views there outlined rather than otherwise. In this and subsequent articles it is hoped to depict subsequent developments, and to illustrate, largely .by means of photographs, some of the principles outlined there in operation.

I would again emphasize the fact that successful breaking-in of primary-forest and secondary-growth country is decided not on any

one single factor, but on a number of factors, any one of which being absent or inefficiently exploited may entirely offset the good of the rest.

Fencing is imperative. < A good hot burn is often half the battle in connection with both primary and secondary burns. Tracking of the primary burn is essential. where much timber is left unburned. The firestick is the cheapest of all hill-country implements, and where it can be used it should be employed in preference to crushing by stock.. Next in importance to the firestick is the grazing animal. Cattle take first place, then wethers; horses in numbers are very effective; and for shrubby secondary growth, such as blackberry, and for tutu, the goat is unexcelled. Where the firestick cannot be effectively used, and where no class of stock is effective, the slash-hook or grubber wielded by the arm of man stands as the third major implement in secondary-growth control. Of recent years there has been added a fourth implementplantpoisonous sprays applied by means of the knapsack spray-pump.

In this and subsequent articles discussing the experiments at Whangamomona it is intended to illustrate these major hill-country implements at work, and to show how each is essentially linked up with the making of a sward by sowing and top-dressing.

1. The Primary Burn.

Thirty-five acres of primary burn have been sown experimentally —5 acres in 1924, 10 acres in 1925, and 20 acres in 1926. The seed mixtures used on these are given in the Journal for August, 1924, and February, 1927. For convenience of reference they are repeated in the following table :

The . table gives the experimental mixtures sown ; the following is the seed mixture recommended after some seven years’ study of the behaviour of the species and the amounts of these that were sown :

Seed Mixture recommended on Primary ■Burns, Whangamomona County.

lb. Perennial rye-grass . . .. . . . . . . . ..12 Italian rye-grass.. .. .. .... .. .. 4 Cocksfoot .. .... . . .. .. .. 8 Crested dogstail .. .. .. .. .. .. .. 3 Poa pratensis .. .. .. .. .. . . .. 1 Brown-top . . • . . .. .... . . ' ... Danthonia pilosa .. . ... .. .. .. .. 3 White clover ... ... ... .. .. ... .. 2 Lotus major ... ' . . . . . . . . . ■ . . ..1 Total per acre .. .. .. .. .. .. 35J

One pound per acre of turnips may also be added, but the usual practice is to sow these before the grass-seed mixture. Unless good control of the burn is possible by way of stocking, the Italian rye-grass should not be included.

Regarding seed mixtures for primary burns, research work in New Zealand and in Britain has demonstrated that the simple mixture is ecologically and economically more sound than is the complicated mixture. The more uniform the conditions over a given area the fewer the species required in any one sowing, but when it comes to primary-burn hill-country sowings there are other aspects to be considered. No bush-burn area is uniform so far as soil conditions are

concerned, nor is it possible economically to make the soil conditions uniform. There are good slopes, small flats, and hollows associated in the same area with steep faces and exposed hard knolls that dry out in the summer. Again the initial conditions as regards soil fertility are quite dissimilar to the fertility conditions that will rule after the wealth of the ash of the primary burn is exhausted.

Thus the primary-burn hill-country seed mixture at the one sowing must provide, for a number of. conditions that do not exist in the ploughable country or even later on in the secondary-growth country. These conditions are : (1) A temporary high fertility in an extremely available form ; (2) a medley of soil-types on ■ any one given area; (3) strong volunteer weed-growth ; (4) ultimate reduction all over the area in the soil - fertility standard. One is therefore forced to abandon the simple seed mixture on hill-country sowings and adopt the more complicated. The above - tabulated seed mixture may be said to cater for three phases.

The turnip, Italian rye-grass, and perennial rye-grass are essentially to exploit the high-fertility phase, and to act as rapidly as possible as a means of holding large numbers of stock to effectively control secondary growth in its establishment phase. The cocksfoot; crested dogstail, white clover, and Poa pratensis, with some perennial ryegrass, will carry well on after the initial flush of high fertility. The brown-top, Danthonia pilosa, and Lotus major are essentially the harder-condition grasses that take up the running first on the lowerfertility aspects — faces, hard knolls, pukahu areas, &c.—and then later, when the rye-grass and cocksfoot weaken, become general as the dominants of the sward. I would here like to allay any fear

of these second-rate grasses usurping the place of the rye-grass, cocksfoot, white clover, and dogstail while the conditions are satisfactory for these latter to thrive. If the soil is naturally fertile, or if. surface fertility can be maintained by top-dressing, these high-productive grasses will keep the second-rate grasses in check, but even on the best country there are steep slopes, poor dry ~ knolls, &c., that cannot economically be maintained at the high-fertility standard demanded by the first-class grasses and clovers.

In the experimental work at Whangamomona this grouping together of species according to habitat has been most marked —so marked in many cases that some settlers have expressed the opinion that the seed sown was not properly mixed or was carelessly sown. Each species

or set of species in the mixture sown becomes dominant in the burn according to the aspect and soil conditions. If it were practicable to sow all aspects with a different seed mixture, then we could use the simple seed mixture to greater effect, but when one comes face to face with the problem of sowing these primary burns the recommendation of even two seed mixtures becomes problematical, particularly when outside labour is employed to do the sowing.

Where it is practicable to vary the seed mixture the rye-grass and cocksfoot should be reduced and the Poa pratensis eliminated on the harder country, and the brown-top and danthonia may be somewhat increased. There is, however, so little variation that I am inclined to recommend keeping to the one standard mixture as given above.

The provision of temporary feed on the primary burn may, offhand, be considered extremely unwise and unsound. The primary burn, it may be claimed, is the one and only chance of getting permanent species into the country, and that this opportunity should not be imperilled by a large growth of temporary feed that will soon run out and leave bare ground. In the 1924 sowings 2| acres were sown with turnips and 21 acres without turnips. After seven years it is not possible to see any difference between the two parts. There are two factors in the primary burn that rule out the objection to temporary elements, particularly in the country under review: (1) The volunteer growth of Scotch thistle, and (2) timber left and secondary growth following after the burn.. It would appear now that from one end of New Zealand to the other the whole of our forests have been . seeded down with seed of Scotch thistle blown in from already established grassland where this weed has been allowed to flower and seed freely.. These seeds remain dormant on the forest floor until the shade of the forest is destroyed by the felling and burning, and unless an intensely hot white burn is secured a crop of the thistle is bound to follow.

These plants in their rosette growth-form occupy more ground than a large-sized turnip, and by their tall growth smother worse than any temporary grass species that could be included in the seed mixture sown. Ido not for a moment recommend the withholding of permanent species from the primary burn. These should certainly be Sown and for all aspects, but where Scotch thistles are bad following the burn a supply of temporary feed in the form of turnips or Italian rye-grass leaves less room for thistles and enables a greater stocking that may tend further to reduce the thistle crop. Logs also occupy much ground, and the removal of these later by secondary burns furnishes a second excellent opportunity of getting in additional permanent grasses and clovers..

. A good hard burn makes a wonderful difference not . only in the amount of Scotch thistle that establishes and in the amount, of log remaining, but also in the amount of secondary growth that comes away the winter following the burn. ' The ground floor of the forest is thickly strewn with seeds and spores of secondary growth, and, unless the burn is sufficiently hot to consume these, a crop of seedlings and sporelings inevitably follows (Figs. 1,2, and 3). Wineberry, fuchsia, mahoe, waterfern, braken fern, and hard fern are probably the most dominant in the Taranaki country under review. Provided stock can get to these plants of wineberry and other , tree seedlings, they soon disappear, being readily eaten. Treading of cattle and sheep and grazing by these animals largely reduces the amount of fern established. This brings up the very important point of tracking the primary burn (Fig. 5). No matter what species have been sown or how good the take, if stock cannot get at the feed owing to timber a mass of secondary growth will result.

A hot burn also reduces pukahu, that spongy mass of roots and leaf-mould which occurs on the floor of most primary forests. In one of our primary-burn sowings in 1926 the seeding was done in the main on such a seed-bed. In 1928 —a dry summerpractically the whole of this pukahu mass was burnt, and much of the area had to be resown. The cleaning-out of pukahu in the original burn makes a great difference to grass establishment and the ultimate sward. . Here again, however, the primary-burn farmer is entirely at the mercy of the elements.

The fencing of the primary burn presents a problem. The value of fences is inestimable as a means of stock-control on the area to be grazed, and their erection is really a great feat, both in skill of erection and in choice of a site. Both are essential in farming hill country. .Ridge boundaries are invariably chosen where at all possible, both from the point of avoiding damage to the fence subsequently by slips and in helping to separate shady faces from sunny faces. All standing trees that later would endanger the fence by falling on it are felled ,when clearing the fence-line.

! The grassing experiments on the primary burn consisted largely in determining a standard primary-burn seed'mixture for the Whangamomona class of country, and it was hoped to glean some information on the part the seed mixture played in avoidance of the fern and scrub successions which normally arise on that country. There is a feeling that if the farmer in the initial stages of breaking in that country had more specific knowledge on . suitable seed mixtures to sow, virtually all secondary-growth problems would disappear or would never arise. This point is of immense importance to decide one way or the other, for on it depends largely the potential value of that country as determined by viewing it in its virgin state. If the country can be successfully grassed by closer attention to seed mixtures, fencing, stocking, &c., without deterioration and the consequent loss of feed and need of further burning and reseeding or necessity to severely punish stock, then the potential value of that country is great, whereas if breaking-in and maintenance costs are high then the original value of that country is low and may even be of a minus nature. r

r The experience of the past seven years on primary-burn grassing in Whangamomona County holds out little hope of avoiding the appearance and spread of certain classes of secondary growth. True, given a [good burn and the most suitable seed mixtures, the class and amount : of secondary growth that puts in an appearance can be largely governed, but I claim on no conditions could a sward entirely free of secondary growth be secured from the offset on primary-burn country of Whangamomona and similar country. Wineberry, fuchsia, water fern, and bracken can largely be controlled, but in controlling these the conditions are rendered extremely favourable for the spread of hard fern, and this secondary growth may dominate the burn after some J four years, despite the seed mixture sown and irrespective of how careful the stocking. The successful establishment of brown-top, Lotus major, and Danthonia pilosa in the initial seeding does greatly slow up the ; spread of hard fern, and even though the swards are overrun with hard fem these species persist to some extent in the hard-fern growth and ■ come away after a secondary burn has been secured.

Secondary burns, then, of logs, timber, and secondary growth must be regarded as part of . the breaking-in processes of hill country from the primary forest, and the cost of reseeding such burns and the loss of feed sustained during the period leading up to a sufficiently dense growth to carry a second fire must all be taken into account in putting an initial value on primary-forest country.

There is no doubt, however, that the seed mixture sown does play an enormous part in the ultimate successful breaking-in of primaryforest country. Even though we have to face hard-fern encroachment

and secondary-timber and hard-fern burns, yet from my experience up to the present the hard-fern phase can be regarded as a step nearer permanent grassland than any other type, of secondary growth. The hard-fern growth of the young burns helps to clean up the timber in subsequent secondary burns (Fig. io). ■ This, however, may be. regarded as a poor recompense for the loss of feed sustained by the actual growth and spread of the hard fern. To my mind, however, no hill country in Taranaki will be free of fern and rubbish until all timber is removed either by rotting out or by burning (Figs. 6 and 7). Logging-up the primary burns, then, should be regarded as a further breaking-in cost, and the more log and stump fires that can be lighted

during those dry unhappily often too short and too far between—the sooner will the country be safe from secondary-growth dangers (Figs. 8 and 9).

The experiments at Aotuhia, on the property of Mr. A. Murphy, may be cited as probably typical of the course a normal primary burn will take under good average farming methods as regards fencing, seeding, and stocking. (Figs. 11 to 13.) In 1924 a good average burn was made and a really good take of grass was secured dominantly . rye - grass, cocksfoot, crested dogstail, white clover, brown-top, and Lotus major—during the early years. The seed mixtures sown on this block are given in Table 1. The lower and better slope received mixture 1, and the upper and harder slope mixture 2. Scotch thistles were, bad on all the easy and

better country, and so dense in parts as to smother out virtually all sown grasses (Fig. 4). The thistle phase lasted well into the second year of the burn, and during this time the grass sward plus the stock held well in hand the water fern, wineberry, and bracken fern established from spores and seeds after the burn. Hard fern, however, at the end of four years had dominated the burn wherever logs and timber stood, or where the grass sward was at all weak. In .1928, four years after the original burn, the area was bad with hard fern. During this year we were fortunate in getting a good secondary fire that cleaned up most of the hard fern and timber. A certain amount of brown-top, Lotus major, and danthonia

came away after the second burn from the original seeding, but it was thought expedient to resow all the area burnt by the secondary fire. The following secondary-burn . seed ' mixture . was sown over approximately three out of the five acres: Perennial rye-gras?, 6 lb; cocksfoot, 4 lb. ; crested dogstail, 4 lb.; brown-top, 2 lb.; Danthonia pilosa, 3 lb. ; paspalum, 2 lb. ; white clover, | lb. ; Lotus major, | lb.

The conditions in 1930 when the photo reproduced in Fig. 11 was taken were an almost complete cover of grass, dominantly brown-top, white clover, Lotus major, Yorkshire fog, cocksfoot, ryegrass, and crested dogstail. Chewings fescue, danthonia, and yarrow showed on the drier knolls, with odd plants general of paspalum and subterranean clover. Some piripiri and patches of hard fern that

were too small to burn in 1928 still remain, and there has been some spread of hard fern from small pieces that were not killed outright by the fire. It remains for the future to see whether the grass sward now existing under normal stocking will hold the hard fern, or whether within a few years there will again be the call for another .secondary fire and subsequent reseeding. No top-dressing has been done on this area.

From experiences to be detailed later in dealing with secondarygrowth control it certainly would appear that a good sward slows up return and spread of hard fern, but some more drastic method may yet have to be employed before 100-per-cent. control of hard fern over the whole area can be attained.

The 1925 and the 1926 seedings (see Table 1) aimed largely at a comparison between dominant first - class grasses and clovers as against heavy seedings of the second-rate grasses such as brown-top and danthonia. . As far as keeping the country clean is concerned, there is practically no difference in any of the mixtures sown, and at the present time both areas have about 30 to 40 per cent, cover of hard fern. In 1930 it was intended to clean up the 1925 sowings, but 'there was too much rain to get a burn.

In striking contrast to the experimental sowings of 1925 was an area adjoining, burnt at the same time but which was not sown until the following spring (Fig. 13).. This area now contains double the amount of secondary growth, mainly hard fern, as the adjoining autumn-sown plots. It serves to show well the importance of the seed mixture and the effect the sward has in giving at least partial control of the secondary growth. Where there is no grass owing to ground missed in seeding, or where only temporary species are sown, or where stock cannot penetrate owing to logs and timber, there is found dense secondary growth of one form or another.

It may be held that so far as grassing the primary burn is concerned the .experiments have not been a great success. Nevertheless, the areas have carried well, and with watching and treatment the trend in favour of grass will be definitely established, a development which it is hoped will mean -easier going for the settler on that class of country.

I would here like to express many thanks to Mr. A. Murphy, of Aotuhia, on whose property most of these experiments have been sown, for the assistance he has rendered to the work on every occasion and in every possible way. (Series to be continued.) . ' '

■i Orchard Registration and Orchard-tax.— The number of registered orchards in the Dominion at 31st March, 1931, was approximately 6,050, representing some .3,000 taxable and 3,050 non-taxable ; was collected in orchardtax by the Department of Agriculture in 1930-31, which amount, less cost of collection, was as usual handed over to the New Zealand Fruitgrowers’ Federation, Ltd., for furthering the interests of the fruitgrowing | industry generally. ‘

* For details of experimental sowings, locations, &c., for 1924 see N.Z. Journal of Agriculture, August, 1924; for 1925 and 1926 sowings see issue for February, 1927 ; and for interim results of these experimental sowings see issue for March and June, 1927.

Mixtures. Sown in 1924. Sown in 1925. Sown in 1926. . I. 2. 2. 33- . 44- 5 - 5- 6. 6. 77- 8. 8. 99- 10. IO. II. II. I3 . 12. 13lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. Perennial rye-grass .. 6 6 6 6 • • 6 6 6 6 6 6 6 6 3 3 Italian rye-grass 2 2 2 . 2 2 2 2 2 2 2 2 2 2 Cocksfoot ' 8 8 15 8 4 15 8 4 15 8 ■4 6 Crested dogstail .. 4 6 4 4 4 4 4 4 4 4 4 4 . 4 . Brown-top .. . .. I 2 4 I 2 3 i I ■ 2 3 I ■ 2 2 Danthonia pilosa 3 6 ■ I 2 3 I 2 3 I 2 2 White clover 4 I I • I I . I I I I I - I ■ I Lotus major.. .. I I I I I I I I I I I I Lotus major.. 4 i 1 2 2 1 4 1 4 I 4 i i 4 I 2 4 4 4 4 4 4 4 ’■■•I. . Lotus hispidus .. i . 4 I I 4 i . i i 1 4 i 1 i 4 I A I Subterranean clover .. 4 i 4 i . i 1 i i i i I i 4 4 4 i 4 1 ■ 4 4 4 4 Yarrow 1 16 15 16 16 is 15 16 15 1 16 16 16 16 13 13 16 . ' 16 16 Poa pratensis 4 4 Paspalum .. .. 4 4 I I I I 2 2 2 2 2 2 2 2 2 2 2 2 2 Chewings fescue I 4 Hard fescue 4 Sheep’s fescue • 4 - • • Rhenish tall fescue 6 4 Meadow foxtail .. 4 ■* ■ Timothy 2 2 Poa trivialis. . I Meadow fescue 6 . • Red clover .. 0 I Rape .. I I .. — — ——— — —— Total per acre .. 46-5 41-7 24-2 24-7 22-7 15-7 32-1 30-6 28-6 20-6 26-6 24-6 •28-6 (1 lb. — 2 oz. ; J 3 ;, lb. = I OZ.)

Experimental Grass-seed Mixtures sown on Primary Burns, Whangamomona County.