THE GRASSLANDS OF NEW ZEALAND.

New Zealand Journal of Agriculture, Volume XXIV, Issue 1, 20 January 1922, Page 8

THE GRASSLANDS OF NEW ZEALAND.

PRINCIPLES OF PASTURE ESTABLISHMENT.

( Continued.)

E. BRUCE LEVY,

Biological Laboratory, Wellington

2. SWAMP LANDS.

Damp, fertile, alluvial Flats.

On lands of this type, if the aim is a truly permanent pasture, the general principles for the establishment of such previously outlined for good average first-class country are departed from to some extent. A mixed pasture is sown down, but all the species sown are not expected to persist as important constituents of the final sward. In other words, a transitional stage must be recognized. There are several species of grasses and clovers which do exceedingly well on damp, fertile country, such as an alluvial river-plain or drained phormium-swamp, and of these meadow-foxtail (Fig. 20) and Poa trivialis (Fig. 21) are the two outstanding species. It is not the aim, however, in the sowings to secure a permanent pasture of these grasses right from the offset. Firstly, the seed of both species is expensive, and, secondly, both plants are fairly slow to establishtwo most important factors. - A mixture somewhat as follows may be sown : Perennial rye-grass, 12 lb. ; cocksfoot, 10 lb. ; timothy, 4 lb. ; Italian rye-grass, 4 lb. ; meadow-foxtail, 4 lb.* ; Poa trivialis, 2 lb.*; red clover, 2 lb. ; alsike, 2 lb. ; white clover, 2 lb. : total, 42 lb. per acre.

In the early years of the pasture the sward will consist of the four first-mentioned grasses and the clovers, and about the fourth' year there will be a decided replacement of these elements by meadow-foxtail and Poa trivialis: The rye-grasses, red clover, and alsike will go out first, but for many years the cocksfoot and timothy will persist, together with a certain amount of rye-grass and white clover. Such an association-namely, meadow-foxtail and Poa trivialis (dominant), together with cocksfoot, timothy, rye-grass, and clover-will form an excellent pasture, and one of this type is undoubtedly the highestyielding permanent grass-pasture (with perhaps the exception of paspalum) that is ever likely to be produced. At this point, when speaking of comparative yields of pastures, one must differentiate between truly permanent pastures, short-rotation pastures, and temporary pastures. Undoubtedly more feed could be produced, practically speaking, on all types of ploughable country by the adoption of a short-rotational system of farming, but where good high-yielding permanent-pastures can be maintained the food produced is cheaper per grass-ton than that produced by the frequent ploughing and resowing necessary in short-rotational farming. Until the rent of the land becomes very high it is a sounder economic proposition to have the required food for the maintenance of the stock produced from more acres than to make fewer acres produce more by costly farm operations. Winter feed, however, must be produced, so that all the

grass in the flush of the season may be utilized, and the team must also be kept active, else it becomes a costly burden. . Consequently a certain area of the farm must be ploughed each year, but that which is ploughed and sown at a high cost per. acre must be made to produce its maximum. Hence the grass-farmer on this type of country should consider the truly permanent pasture as the cheapest food for his stock (provided the rent per acre is not unduly high); but to ensure winter feed and that there should be no energy lying idle on the farm certain ploughing and resowing must be done. For many years to come, however, the permanent pasture will figure very largely oh the farm on this type of country, and in the establishment and life-history of such pasture a distinct transitional stage will now be recognized.

The transition which occurs is essentially a . desirable . one, but it may so happen on the class of land under consideration that a more aggressive species even than meadow-foxtail and Poa- trivialis may come in, and then the -latter will be suppressed by their more vigorous rival. Again, the vigour of the invader may be enhanced by the fact that the herbage such plant produces is unpalatable to stock. This aids the invader in that the more palatable plants are kept down by the grazing animals, and consequently their power to resist is weakened owing to their reduced capacity to smother. An undesirable succession follows. Such an example is seen in many of these fertile

lands where tall fescue {Festuca arundinacea) (Fig. 22) has come in and replaced the original grass association. Tall fescue is not only of low palatability, but it has as an ally a fungus disease known as ergot {Claviceps purpurea). Tall fescue is particularly prone to the attack of ergot, and if the stock are forced on to such pastures they are particularly liable to contract ergotism by partaking of the ergotinfested grass. Thus is it unsafe to stock heavily, and this factor makes control by stocking methods an impossibility. The avoidance of this tall-fescue succession is one of the outstanding features of grass-farming on the type of country under consideration.

Phormium (“ Flax ) Swamp Type.

The phormium crop as a rule represents a succession, phormium becoming the dominant vegetation, the transition being one from stunted Phormium tenax, raupo {Typha angustifolia}, niggerhead {Carex secta), and Mariscus ustulatus, following on the drainage of the area. While the phormium flourishes it is without doubt the most remunerative crop, that can be grown, but it frequently gives way, and particularly so of later years, where the disease known as yellow-leaf is. prevalent, to a succession of Yorkshire fog, tall fescue, bracken-fern, spear-thistle, &c. Generally speaking, good phormium areas are of first-class quality,, and represent land admirably fitted for a permanent pasture of the type recommended previously for rich damp alluvial river deposits. There is, however, one feature to be guarded against-namely, that these phormium swamps are frequently not sufficiently consolidated to ensure successful permanent pasture establishment on the original breakingup of the area. A process of consolidation must then precede the permanent-pasture sowing, and the importance of . this will be made clearer when the peat-swamp lands (to be dealt with later) have been considered.

River-flood-area Type.

Certain soils are waterlogged in the winter and sufficiently dry in the summer to allow of stocking. Owing to such areas being too low-lying to drain satisfactorily, some attempt must be made to grass them with species that will tolerate wet conditions and even withstand periodic inundation for several weeks at a time. Areas near large rivers, for instance, may be inundated in the winter-time, and no amount of drainage would prevent this unless flood-gates and embankments were erected. Here, then, must be chosen grasses and clovers fitted to stand such conditions, but in this, unfortunately,- the choice is limited.. Of the regular plants at service timothy, meadow-foxtail, Poa trivialis, red-top, paspalum, Yorkshire fog, and Lotus major are available. Strawberry clover does exceedingly well on soils liable to be inundated by brackish water, but seed of this plant is very expensive. A unique plant for flood-areas is sweet floating-grass ceria fluitans). This grass, will thrive only in water-saturated soils, and will stand submergence for a month or so at a time. This is possible in virtue of the plant being able to elongate its stems and to spread out its leaves on -the surface- of the water. Ordinary green plants with which we deal in our pastures are absolutely dependent for their existence upon a supply of air so that ordinary respiratory processes may go on. It will be obvious, therefore, that unless a plant when

submerged can reach the surface of the water by elongation of its stems it will soon suffocate and die. Sweet floating-grass has this character fully developed, and the plant forms on the surface of the water a regular floating .meadow. One of the quaintest of sights is to see cattle-beasts wading up to their bellies in water and. eating this grass from off the surface (Fig. 23). When the flood-waters have subsided the grass takes on its ordinary ground form, and produces an enormous amount of perhaps the most palatable herbage 'of all our grasses (Fig. 24). Unfortunately, seed of this grass is not available at

the present time, the little that was imported before the war having been procured from Central Europe. The plant, however, illustrates very well the character-requirements plants should possess to occupy this particular type of land. It will be noted that on these very rich soils the tendency is for the pasture or grass cover to become more or less of a pure. association. This is accounted for by the fact that the total set of. characters of any one grass is capable of full development owing to the unlimited available food-supply. Any plant that possesses one character above another plant holds the advantage when the conditions are favourable to the development of that extra character. Of all our pasture-plants none are identically alike in character, consequently, on these very rich soils, when a mixture is sown that plant which possesses the additional character will finally dominate the association. On poorer land that self-same character, owing to a reduced available food-supply or to

the presence of certain' physical conditions, may not be developed, and hence the grass may be just able to hold its own in a mixed association. Meadow-foxtail is an. excellent example in this respect. This grass, in virtue of its short tillering rootstock, is able to spread out. slowly and. occupy the land. Where rich damp conditions prevail this tillering character is fully developed and the spread of this species ensured, but on soil just a little drier such character is very feebly developed. Hence meadow-foxtail rarely assumes an important position in pastures on such soils, although it may figure well as a constituent of the mixed pasture. Again, pure sowings, provided the grass is rapid to establish, are generally more permanent on these rich soils than on any other. Thus pure timothy pastures may . be maintained for twenty years or more. Even short-lived species may often form a permanent sole of grass owing to the fact that reseeding can and does take place on these damp rich soils (Fig. 25). Italian rye-grass may reseed itself each year in this way, and figure permanently in the pasture: - Crested dogstail forms an extremely close sole in virtue of this same attribute. Spreading by seed, however, is not common to many grasses on other types of soil, and it may be asserted as a definite fact that there is little establishment from seed unless the grass flourishes naturally on such soils'. Italian rye-grass seed may fall and germinate at the first rains of autumn, but the plants remain spindly and die out as soon as dry weather arrives. In most cases the conditions are tod severe for selfestablishment by reseeding, but on rich damp soils establishment by reseeding is quite common. • ‘ ■ ■ • (To be continued.) '

* Only tested seed should be sown, as the germination of these seeds is frequently very low.