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Chapter 2
Types of British Grassland
There is substantial evidence which indicates that the greater part of lowland Britain was at one time under more or less dense forest. What is less generally realized is that, given sufficient time and the complete absence of man and animal, most, if not all, of this land would revert once more to forest of one kind or another. There is, therefore, relatively little true natural grassland in this country. It is probable that our various grades of moorland and hill grazings come nearest to natural grassland, although even here the trend is always, and in the absence of grazing animals, towards the succession to fern or heather, which in themselves are often the forerunners of birch and other types of scrub or woodland. Within the confines of the British Isles, therefore, it is hardly accurate to speak of natural as opposed to artificially induced grasslands -- for the simple reason that the vast bulk of, if not all, our grasslands, including the moorland grazings, are, in fact, artificial products, the direct outcome of centuries of biotic influence.
We may, therefore, more appropriately begin by dividing our grasslands into two main types, namely (1) Uncultivated grasslands, which would include the greater part of our rough and hill grazings, and (2) Cultivated grasslands, which include the permanent pastures and meadows of the lowlands as well as the acreage in leys of all descriptions. These two large divisions will be discussed and described in some little detail. It must be emphasized, however, that there is no exact line of demarcation as between these two groups; rather do they tend at a number of points to merge the one into the other. Nor is there any sharp and exact line of distinction between leys and permanent grassland as such. The transition from ley to permanent pasture is gradual, the longer a ley remains in grass, the more it tends to resemble permanent grass. The ley, however, may be said to have ceased its function as a ley and to have taken on the attributes of permanent grass when the species originally sown therein have been largely replaced by unsown grasses, clovers and other plants.Uncultivated Grasslands
In the main, these are represented by our rough and hill grazings. They include the moorlands of the north and west of Britain as well as the downlands and many of the heaths of south and east England. On the acid soils of the west and north, the following types are among the most important with respect to the acreages involved:
- Molinia moors, where Molinia caerulea dominates the vegetation on more or less deep peat.
- Cotton grass (Eriophorum spp.) moors, usually on deep, waterlogged peat.
- Deer grass (Scirpus caespitosus), also on deep, ill-drained peat.
- Heath rush (Juncus squarrosus) on badly drained peaty soils.
- Upland bog with rushes (Juncus effusus et articulatus) and Sphagnum.
- Nardus moors, with Nardus stricta as the chief grass, usually on steep hillsides and very shallow, acid peat.
- Nardus with fescue (F. ovina), normally on shallow, well-drained peat.
- Bilberry (Vaccinium) moors, with Nardus and fescue, on steep hillsides, well-drained peat.
- Fescue pastures, chiefly F. ovina, on siliceous soils of good drainage.
- Bracken fern with fescue on siliceous (mineral) soils of good depth.
- Fescue-Agrostis pastures (including Agrostis setacea) on Devon and Cornish moors).
- The seaside fescue pastures, including the estuarine salt marshes and also areas of sand dunes (marram grass characteristically dominant).
In addition to the foregoing types, there occur in the south and east of England certain other sharply defined types of uncultivated grasslands, among which are the following:
- The uncultivated Downs dominated by Sheep's Fescue, Bromus erectus, several oatgrasses, (Avena spp.) and associated with an extremely varied and rich flora. A closely similar type of uncultivated grassland is found on the Cotswolds and on other oolitic escarpments throughout England, although perhaps torgrass (Brachypodium pinnatum) attains to greater prominence here than on the chalkdowns proper.
- The heaths of south and east England tend to carry a more varied herbage than those of the west and north. In places sheep's fescue dominates the swards, elsewhere, as on the Brecklands of East Anglia, heather, sand sedge (Carex arenaria). and sometimes (as on heavily rabbit-infested lands) various mosses will predominate. Many of the south of England heaths lying on both Greensands and on the Eocene formations (including Reading and Bagshot beds) tend towards dry heather moor, with pockets of Molinia, bracken fern and scrubby thickets. These latter are transition stages developing towards the woodland phase, referred to in a subsequent chapter.
- There remain the grasslands of the uncultivated fen, which are to be found chiefly in east England, but also in a few other places, but always on peats, usually with a high lime status. This class of fen will generally be badly drained, and carries a varied flora, which includes Molinia, reedgrass (Arundo), Phalaris arundinacea, various sedges (Carex spp.) and is characteristically associated with birch and willow scrub and other transitional stages indicating reversion towards swamp forest.
Cultivated Grasslands
These occupy in England and Wales a much greater aggregate acreage of land than is accounted for by the rough and hill grazings. In the main, the latter are either wholly unenclosed or are to be found within relatively large enclosures.
The cultivated grasslands on the other hand occur chiefly on fields and other small enclosures. These grasslands may conveniently be grouped into two classes, namely (1) the temporary leys and (2) permanent grassland.
The Leys
represent grasslands which have been recently sown out with a seeds mixture following a period of ploughing or other arable cultivation. The temporary ley may, depending on the seeds mixture employed and the management afforded to it, be one of long duration (say from four to a maximum of say fifteen years) or alternatively of short duration (one to three years). After a ley, whatever its description, and on whatever soil type it occurs, has been down for a period of years, it tends to take on the general attributes of permanent grassland and gradually merges into permanent grass. Most leys , even when managed superbly and on the most fertile of soils, will have ceased to function as leys after about the tenth to fifteenth year. On the poorer classes of soil, or under indifferent conditions of management, and with inadequate manuring, the ley is ready for ploughing after about the fifth year from sowing. The outrun ley is no longer highly productive, and in this respect may be of less value than permanent grass. Under a properly conducted system of ley farming, the temporary ley will have been ploughed up long before it has lost the bulk of its sown species; ploughed up, that is, before it has become outrun. The effective life of the ley will depend not only upon the seeds mixture originally employed, but also upon the management of the ley as well as upon soil fertility both natural and induced.
The major species of greatest value in Britain for the production of high-class leys are the ryegrasses, cocksfoot and timothy, together with red and white clover. It will be further emphasized in a later chapter that leys may, by design, be dominated by any one of these species. It is sound practice to think in terms of special purpose leys, of ryegrass leys or cocksfoot leys, and of timothy leys, each of which will, of course, be associated with the clovers. We may now turn to a more detailed consideration of the permanent grasslands of this country.
The Permanent Pastures
and meadows of Britain have been classified by Davies according to their botanical composition, and it has been shown that in a general way the botanical classification carries a close resemblance to a classification based on agricultural evaluation. The best pastures and meadows (and we are now speaking only of permanent grass) are those in which perennial ryegrass and white clover predominate. Even in the best permanent pastures there will be a proportion of inferior grasses, chief of which is bent (Agrostis spp.). As the proportion of Agrostis or bent increases, so in general the proportion of ryegrass is decreased, and there is a corresponding lowering in the productive capacity (and therefore in the agricultural worth) of the pasture or meadow. The pasture in which Agrostis predominates to the exclusion of ryegrass and other grasses of superior value is, therefore, less valuable from a production standpoint than the ryegrass pasture. Similarly, pastures in which the fine-leaved fescues are dominant are less valuable generally than the Agrostis pastures. (On lowland grasslands, red fescue [Festuca rubra and its varieties]; whereas on uplands and the heaths, sheep's fescue [F. ovina] is the more abundant.) This, then, may be used as the basis of classification, and in a recently conducted survey of the grasslands of England and Wales, the following types were recognized among the permanent grasslands of the country:
1. First-grade Ryegrass Pastures in which perennial ryegrass contributed 30 per cent or more to the sward. The remaining herbage usually consisted of wild white clover in large amount, together with larger or smaller quantities of Agrostis, fescues and a variety of other plants. The best pastures to be found in parts of the Midlands, as well as on the Romney and other marshes, conform to this type. Pastures of this grade show the highest aggregate annual production among all our permanent grasslands as measured by, say, meat produced per acre per annum. The standard of grassland management is usually very high, and this, together with a naturally fertile soil, is the major factor in pasture maintenance. First-class ryegrass pastures in England and Wales total to an acreage of 251,000 acres or 1.6 per cent of the total permanent grassland in 1938.
2. Second-grade Ryegrass Pastures with a 15-30 percent (usually fluctuating around 20 per cent) contribution of perennial ryegrass. With the reduction in perennial ryegrass, there is a corresponding increase in the percentage of Agrostis, fescue, dogstail and other plants. Pastures of this type are commonly to be met with in our best dairying districts, such as the Cheshire Plain, the Somerset marshes, and certain parts of the Blackmore Vale in Dorset. The soils are usually fertile and well drained, and the standard of pasture management is reasonably good. The aggregate acreage of this class of pasture is much larger than that of the first-grade ryegrass type. In England and Wales there are some 912,000 acres of second-grade ryegrass, as compared with 251,000 acres of first-grade ryegrass pastures.
3. Third-grade Ryegrass Pastures (=Agrostis with ryegrass). These occupy a very much larger aggregate acreage than either of the two preceding groups. Our recent survey shows that there were (1938) 4,317,000 acres of third-grade ryegrass pastures in England and Wales. Pastures of this type may be defined as Agrostis dominant but containing perennial ryegrass to the extent of about 10 per cent (fluctuating between the limits of 5-15 per cent). White clover is usually fairly abundant, while various inferior grasses and weeds make an appreciable aggregate contribution to the herbage. On the more fertile situations, meadow fescue, meadow foxtail and rough-stalked meadow grass may each make telling contributions to the swards. Third-grade ryegrass pastures are widespread over the whole country, and are characteristic of the soils of average-to-good fertility, including many of the valley grasslands of our chief river systems -- parts of the Thames, Severn, Trent, Dee and Exe valleys, to name but a few representative situations.
Many of the permanent pastures in the chief dairying districts of the country conform to this group, and there are scattered examples everywhere. Even in the poorest grassland districts, there will be one or two third-grade ryegrass pastures on almost every farm. The well-grazed and heavily dunged homestead fields usually conform to this type of sward. In more fertile districts, and particularly in the valleys, these swards are appraised, insomuch as they are said to be capable of fattening a bullock an acre. Having regard to their potential production, the fattening of a bullock to the acre does not seem to bear high merit as a performance. In comparison with high-class leys, this standard of production is decidedly low, and in any case, most of the cattle beasts fed on these permanent grasslands will be normally finished off with cake.
4. Agrostis Pastures. This group occupies by far the largest aggregate acreage of any pasture type in Britain, whether among the cultivated or the uncultivated pastures. Agrostis predominates in the herbage, ryegrass is absent or is present in no more than negligible amount. White clover is usually a sward contributor, except in the more derelict areas, while dogstail, fescues, sweet vernal, Yorkshire fog and the like are often important species. On fertile fields, meadow foxtail and rough-stalked meadow grass take an important place in the pasture or meadow, while on the soils of the Lias and other clays in the Midlands, torgrass, red fescue and a host of miscellaneous plants are to be found in the swards. Some of these latter grasslands represent transition stages between Agrostis-with-fescue pastures and fescue (F. rubra) pastures as such.
Agrostis pasture in its most characteristic form may be said to be typical acid grassland. On the acid soils of Wales and the West of England, Agrostis pasture represents the average pasture type over huge areas of that countryside. The herbage in general lacks variety, when compared with the pastures of the lime-rich soils, such, for example, as those derived from the Lias, Oolite or Chalk. Agrostis pastures are, however, well developed in most parts of the country. They provide the background of the permanent grassland and outrun leys of the west and north; there are large acreages of Agrostis pasture throughout the Midlands and the south of England, while the grasslands of the weald of Kent, Surrey and Sussex are predominantly of this type. It has been calculated on the basis of the evidence of the grassland survey that Agrostis pastures in England and Wales (1938) aggregated to 9,580,000 acres, a figure which represented 60.6 per cent of the total permanent grassland south of the Tweed (excluding rough and hill grazings). No such survey has been concluded in Scotland or Ireland, but from our general knowledge of those grasslands, we would suggest that the percentage of ordinary Agrostis pastures is, to say the least, no lower than in England and Wales. Agrostis pastures must be regarded as units of low production. They are typically rearing pastures for store animals, and it is exceptional to find an Agrostis pasture capable of fattening prime lamb or cattle beast without excessive feeding of concentrate. Agrostis pastures are the most abundant type throughout many of the large dairying districts, and where large amounts of cake and other concentrated foods were in peace-time being fed to the cows throughout the summer.
5. Agrostis with Rushes and Sedges. On wet soils, and where drainage is impeded, Agrostis pastures quickly degenerate and become invaded by rushes and sedges. (Variously the commonrush [Juncus effusus], blue rush [J. glaucus] and/or jointed rush [J. articulatus var.], depending on soil and locality.) There are appreciably large acreages of such lands all through the valleys of Wales and the west, as well as in many parts of the Midlands and throughout the East Anglian valleys. The total area of this class of pasture in England and Wales in 1938 was 734,000 acres, representing 4.6 per cent of the total area of permanent grassland. In addition to the rush-invaded pastures, there is the yet more degenerate, but closely allied, lowland Molinia pasture occurring in the western valleys, and which, in aggregate, covers a fairly large area of land. These enclosed and lowland Molinia pastures (sometimes Molinia with Nardus, but more often Molinia with rushes) are, without doubt, degenerated Agrostis pastures which have been allowed to go derelict often over a prolonged period of time. In their present state they appear to be almost worthless, either for grazing or meadow. If improved by burning and grazing, the balance of the vegetation can rapidly be shifted towards Agrostis with rushes and under heavy grazing, coupled with the frequent use of the mowing machine to deal with the rushes, to ordinary Agrostis pastures.
6. Agrostis-with-Fescue. In general, the Agrostis pasture with excess of fine-leaved fescue is agriculturally less valuable than the ordinary Agrostis-with-white clover pasture. There is a fairly large acreage of Agrostis-with-fescue pasture not only on the semi-uplands of Wales and the west of England, but at low elevation in north England. The pastures of parts of Northumberland and Durham and the industrial areas of Yorkshire, Derby and Stafford are characterized by excess of red fescue. The same is true in many parts of industrial Lancashire, Cheshire, Shropshire and South Wales. This seems to indicate that red fescue as compared with Agrostis is better able to withstand the acid soil conditions set up in areas lying in close proximity to coal-mining and other industrial activities.
The data relative to acreages which are summarized in Table 1 are based on a survey of the grasslands of England carried out in 1938-40. The Welsh grasslands had been previously surveyed. The permanent grasslands of England and Wales in 1938 occupied 15,794,000 acres. The great proportion of these were represented by third and fourth rate grasslands in which Agrostis was almost everywhere the dominant grass. Ordinary Agrostis pastures, many of which would be associated with red fescue and other inferior grasses, accounted for over 9.5 million acres, or 60.6 per cent of the total area of permanent grassland. Third-grade pastures where Agrostis dominated, but to which perennial ryegrass also made appreciable contribution, accounted for 27.4 per cent of the permanent grass, whereas the first and second grade ryegrass pastures contributed only 1.6 per cent and 5.8 per cent respectively. The proportion of the different grades of lowland pastures as between contrasting counties is of interest. For example, Leicestershire, a well-recognized grass county, with considerable areas of high-quality feeding pastures, had (in 1938) some 136,400 acres of ordinary Agrostis pastures (fourth grade) as against only 26,300 acres of really first-grade pastures. Pastures of the third and fourth grade represented nearly 75 per cent of the permanent grasslands of the county. In Northumberland, where the aggregate of permanent grass together with rough grazings amounted to just over a million acres (the rough and hill grazings accounting for 45.8 per cent of this), there were nearly 300,000 acres of Agrostis pastures as against 7,300 acres of first grade ryegrass pastures.
Table 1.
To show the acreage of different types of 'pasture' both cultivated and uncultivated in England and Wales (1938). (Based on the grassland survey conducted 1938-40.)Group Type Area in 1,000 acres Percent of Permanent Pastures Permanent Pastures 1st grade (ryegrass) pastures 251 1.6 2nd grade (ryegrass) pastures 912 5.8 3rd grade (Agrostis-with-ryegrass) pastures 4,317 27.4 4th grade (Agrostis or Agrostis-with-fescue 9,580 60.6 5th grade (Agrostis-fescue with rushes and sedges) 734 4.6 Total Permanent Grassland 15,794 100.0 - - - Per cent of Rough Grazings Rough and Hill Grazings (uncultivated) Fescue pastures, including hill fescues and the downs 1,499 27.1 Fescue-with-Agrostis, invaded by dense bracken fern 406 7.3 Fescue-with-Agrostis, invaded by mixed fern, gorse and scrub 110 2.0 Nardus moors with fescue, rushes, bilberry, heather 428 7.8 Molinia moors, including mixed heather, fern and scrub 282 5.1 Mixed Molinia-with-Nardus moor 866 15.7 Heather moor 794 14.4 Heather 'Fell' 361 6.5 Cotton grass and deer grass moor 414 7.5 Lowland heaths (New Forest and Breckland type) 199 3.6 Dense thorn and scrub-infested fields 12 0.2 Lowland bog, swamp and fen 'carr' 66 1.2 Coastal dunes and estuarine saltings 88 1.6 Total rough and hill grazings 5,525 100.0
Essex is a large arable county, but even so, its permanent grassland amounted (before the war) to about 333,000 acres, of which more than half were Agrostis pastures, whereas pastures of the highest standard amounted to no more than 3,700 acres, or slightly over 1.1 per cent of the grassland area in the county. Devonshire had over one million acres of grassland (1938) of which rough grazings amounted to 17 per cent. Of the remaining acreage of permanent pastures, some 665,900 acres, or nearly 75 per cent, were ordinary Agrostis pastures, while only 0.4 per cent (3,400 acres) were in first-grade ryegrass swards.
The large aggregate acreages in England and Wales of third-grade and fourth-grade pastures (and which are emphasized by the data shown in Table 1), are, therefore, not confined to certain districts or to certain counties, but are the commonest types throughout the country in all but a few parishes in the best feeding and one or two dairying districts. The figures, and the state of affairs which they demonstrate, are a standing reproach to our methods of farming, methods born of the complete lack of interest the nation at large has for generations taken in the affairs of agriculture and the countryside.References
DAVIES, WILLIAM (1941). 'Grassland Map of England and Wales.' Journ. Min. Agric. Vol. 48. No. 2.
STAPLEDON, R. G. and DAVIES, WILLIAM (1946) et al. 'Vegetation: Grasslands of England and Wales.' Ordnance Survey. London.
WILLIAMS, T. E. and DAVIS, A. G. (1946). 'A Grassland Survey of the Monmouthshire Moors.' Journ. British Grassland Soc. Vol. 1.
Next: 3. Grassland Succession
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