Grass and Grassland - Ian Moore

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(b) wearing capacity and ability to recover from harsh treatment, are of much more importance, while the landscape gardener must also look for very different qualities in grasses to form ornamental lawns or for foliage work in border and greenhouse. Quite naturally, in the case of both groundsman and gardener, the species used are often different from those used in agriculture, and in these pages I have concentrated on the latter.

      The yield of herbage produced by any grass, which is the farmer’s first consideration in making a selection, depends upon its tillering capacity, the facility with which it recovers from cutting or grazing, and the duration of growth each season. An excellent illustration is obtained by comparing perennial ryegrass and bent grass. The former tillers freely and grows steadily from early spring until late in the autumn and indeed, in the mild wet south-west of England it grows all the year round. In contrast to this, bent grass grows for a short period only and yields comparatively little bulk, and in consequence is discarded by the farmer as being of no value. To him it is in fact a weed.

      Then the ability of a grass to recover from cutting or grazing is also of great importance, defoliation being more favourable to the development of young tillers in some species than in others. Recent work has tended to stress the importance of the influence of intensity of defoliation on the yielding capacity of grasses. It appears that by leaving some growth—say one to two inches—when cutting or grazing a sward, more rapid recovery of growth follows, and hence more bulk or weight of grass over the whole season is obtained, than when animals are allowed to graze tightly to the ground or the mowing machine blades are set as closely as possible to the bare earth. The full answer is not yet known, for species vary in this respect and are also subject to seasonal variations.

      While most grasses are palatable if eaten in the early stages of growth, quite a number develop harsh or hairy leaves, or even spines on the leaf margins, as they grow older, and hence are rejected by stock. A grass which may be highly valuable in all other respects can be rendered useless by this factor; Yorkshire fog and the coarser forms of tall fescue are typical examples. In practice it is not always possible to utilise a field at the ideal stage of growth, when the grass is most palatable to stock, and thus grasses which retain their palatability over a long period are particularly valuable. Yield and feeding value are complementary factors, the one without the other being useless to the farmer. In this connection the structure of the grass is important, for species with a high proportion of leaf to stem are much more valuable than stemmy ones, since the leaves are more palatable and contain more protein than the stalks. Grasses become coarse and stemmy with a corresponding reduction in feeding value as they reach the seeding stage. Plant breeders of recent years have endeavoured, therefore, to produce strains of grasses with a high proportion of leaf to stem and with a natural reluctance to produce flowering heads.

      From the farming angle as well as the ornamental, a capacity to remain green during the winter months is important. This extends the grazing season and reduces the need for expensive artificial feeding of livestock. Certain varieties of meadow foxtail and red fescue, for instance, have been bred to produce leafage during February and March.

      In the last thirty years a great deal of attention has been paid to variations of type within each grass species. Perennial ryegrass, for example, may be tufted, stemmy and short-lived or it may be leafy and persistent. Some types are very prostrate in growth whilst others are erect. Some are very palatable, others less so. The same comments are applicable to all the important species of commercial value such as cocksfoot, timothy, and meadow fescue, and these are classified into what are technically known as “cultivars” (but more familiarly as varieties or strains), and multiplication by division and seed of these strains is carried out on a large scale.

      It is very evident there can be no simple answer to the question, “Which is the best grass?” Quite apart from the great variations which we have seen exist within the grasses themselves, the complexity of the problem is magnified by varying systems of management whether for grazing or conservation, by the use of different seeds mixtures, by fertiliser and herbicidal treatment, by disease and insect pest, and by the varying requirements of sheep and cattle. The whole fascinating study is unfolded in the following chapters.

      CHAPTER 4 TYPES OF BRITISH GRASSLAND

      Centuries of biotic influence have brought about the formation of our so-called natural types of grassland, for even the wild stretches of hill and moorland, which to most people epitomise natural grassland, owe their existence to the influence of countless generations of grazing animals, particularly sheep. Without man’s influence heather, bracken, and scrubby growth soon colonise the land to act as the forerunners of bush, pine and rowan until a dense forest growth occupies the countryside. Let us, therefore, be precise and speak of uncultivated and cultivated grassland. The former group includes moors, downs, wolds, heaths and fens, broadly termed rough grazings, while the latter includes the rich permanent pastures and meadows which are “cultivated” by regular mechanical treatment with harrows and rollers and receive periodic applications of the essential plant nutrients though the turf is left undisturbed. Included in this group is the ley or short duration grassland which is ploughed periodically. The subdivisions are clearly seen in table 4:

      TABLE 4. SUBDIVISIONS OF GRASSLAND

Uncultivated grassland Cultivated grassland
moors: (north and west of Britain) permanent temporary
downs: (south and east) pastures leys
heaths: (south and east) and of
fens: (mainly in the east) meadows varying
duration

      The transition from ley to permanent pasture or meadows, thence to rough grazing and scrub, and finally to forest, is an orderly, gradual process, the different phases being clearly recognisable yet merging one with another. The great areas of rough grazings are known to all countrymen and townsmen alike and a brief outline of the different types of grassland in this group will give added interest to the countryside.

      The soil of our moorland areas, including those of Scotland and the Lake District, the Pennines, the Yorkshire moors of the north-east, the Welsh mountains, and the moors of Cornwall, Devon and Somerset, is acid or “sour” and a marked lime shortage is invariably associated with a deficiency in phosphate and potash. Under such conditions our useful grasses and clovers cannot survive and the flora is very restricted and specialised, the degree of acidity, the rainfall and the drainage determining the specific type of herbage found in any particular stretch of moor. Free-draining land is often in close proximity to bog, but in the majority of cases the sterile condition of the soil has resulted in an accumulation of undecomposed vegetation, “mat,” near the surface and the grassland is said to be “matted.”

      On the wetter soils the dominant species is often flying bent (Molinia), the long straws of which were once used by country people for making stiff carpet brushes. Should the peat be waterlogged then cotton grass, deer grass, heath or square-stemmed rush will be found in varying amounts. If the peat is well drained, as on hill sides and knolls, the soil still being very acid, then the dominant grass is matgrass, so named because it grows in dense matted tufts, the hard bristle-like wiry leaves being much too tough for cattle or sheep to eat. Often associated with matgrass will

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