Grass and Grassland

The history of our grasses from the Ice Age can be traced through the pollen grains which have remained preserved for thousands of years in peat bogs. The pollen of many plants, including the bulk of our forest trees, is liberated in vast showers of golden dust, and is wind-borne for considerable distances. Even the centres of large cities receive their quota as the sufferers from hay fever know to their cost. Each pollen grain is protected by a thin skin which is highly resistant to decay; consequently when down the ages millions upon millions of these grains have settled on the land and been covered by further deposits they have not disintegrated. It is possible in the laboratory to separate the pollen grains from soil particles obtained by the simple process of boring into ancient lake beds and peat bogs. These can be identified and in this way precise records of the local vegetation can be secured from the glacial period onwards. Such information can then be cross-checked with any geological and archaeological data available enabling a complete picture to be built up.

With the improvement in climate after the final retreat of the ice, the country was covered with vast woods of pine and birch, the only grassland being in parts of the forest cleared by early man. Then elm, oak, and hazel scrub gradually became established as conditions improved.

What of the livestock whose development is intimately interwoven with that of the grasses? Animals clearly related to our present-day grazing animals appear in the fossil records early in the Eocene period, some seventy million years ago. Judging by the structure and arrangement of their teeth, these early ungulates were, however, mainly browsing animals, feeding by cropping the leaves of forest trees. This seems to have been true throughout the Eocene and the succeeding Oligocene period, but at the opening of the Miocene, some forty million years later, there appears to have been a decrease in rainfall and a consequent diminution of forest cover, leaving grasses and other low-growing plants in possession of the plains, both in the Old and the New World. True grazing animals, closely related to modern types, then developed. Antelopes and sheep are recognisable from the Upper Miocene, and oxen, goats, and horses from the following Pliocene period.

The pastures which supplied the needs of the stock of primitive man were as can be imagined but a pale shadow of the excellent swards of to-day. It is unlikely that they did more than keep mature cattle alive, although for a short period during the summer months the best milk cows might have produced a few pints of milk per day, compared to the four, five or six gallons expected now. Nor was the farmer of those times conversant with the needs of the soil, and the constant leaching of nutrients by rain water and the removal of minerals by the stock themselves in the herbage consumed meant that phosphate, lime and potash deficiencies were common. As the fertility of the cultivated ground fell to the point where the yield of grain no longer rewarded the efforts of cultivation, this ground was abandoned. The former arable was then allowed to revert to some form of grass again. Such conditions favour the growth of mat grass (Nardus stricta), purple moor grass (Molinia caerulea) sheep’s fescue (Festuca ovina), bent (Agrostis spp.), bromes (Bromus spp.) and the oat grasses (Arrhena-therum, Trisetum and Helictotrichon), grasses of poor feeding value. These are in marked contrast to the broad-leaved succulent grasses of high feeding value which comprise a good pasture. Farm stock in those early times was small and stunted as shown by the skeletons which have been found and this was only to be expected under such conditions.

The conversion from forest to pasture can be seen in minature on the broad verge of many a farm road crossing or common. Nearest the road, the constant trampling back and forth of cattle, sheep, and horses promotes the growth of the best pasture grasses, such as the ryegrasses (Lolium spp.) and the meadow grasses (Poa spp.) with wild white clover (Trifolium repens) and probably bird’s foot trefoil (Lotus corniculatus). As the trampling and grazing become less intensive further from the road-side so the bents (Agrostis spp.) the fescues (Festuca spp.) and Yorkshire fog (Holcus lanatus) become more dominant and these in turn are replaced by coarser grasses, the tall fescues, tussock grass (Deschampsia caespitosa) and oat grasses until bramble, hazel, blackthorn, wild rose, and hawthorn dominate the scene. It is then only a short step to true forest. This gradual progression from good grass to forest follows any change which results in less intensive grazing or neglect. Should a field be ranched, allowing only a few head of stock on a large acreage of grassland, as opposed to close grazing where many stock are concentrated in a field, or more especially if grassland is allowed to become derelict, young saplings of forest trees spring up and the once valuable turf soon becomes colonised by coarse grasses and scrubby growths reverting back in time to the original forest from which the pasture had been won by the efforts of man.

Not until about 50 B.C. was the liming and marling of fields practised by the Belgae as a means of replenishing the fertility of the soil, and it was very much later that the droppings of animals were collected to be spread as farmyard manure. We owe much to the Belgae; with the eight-ox plough which they introduced, cultivation on a much bigger scale became possible and, moreover, they affected considerable forest clearance with their implements. So successful were their efforts, indeed, that corn and cattle were exported to the Continent, and when Caesar invaded Britain he was able to supply the food needs of his troops from the soil of Kent.

The Romans did little for the grassland of Britain, but after they had withdrawn, the Anglo-Saxon invaders, with great vigour, began clearing more forest land and converting lowland soils into meadows and cornfields. Many more were enclosed for better cropping and compact villages were created. These were usually surrounded by large open fields in which each settler had a number of scattered strips, some for cultivation and others to be mown for hay, the underlying principle being to divide up as evenly as possible the different types of soil with their varying levels of fertility. After harvest the arable and the meadow land were opened for common grazing, the stock feeding on the straw which was left on the arable ground, together with any growth of grass which had been made since the hay was carted. The Anglo-Saxons were really the first farmers to appreciate the need for adequate pasture during the grazing season and the necessity of safeguarding their stock in winter time with a good supply of hay. By so doing, the former practice of slaughtering in the autumn all the stock which could not fend for itself during the winter was avoided. Each occupier of thirty acres was given at the beginning of his tenancy a cow, two oxen, and six sheep by the lord of the manor and there were no farmers who merely rented the land as they do now. It was possible to increase the acreage of pasture by paying money rent to the lord or by rendering services in the form of additional ploughing. The Anglo-Saxon period was fruitful for Britain, and central and eastern England was dotted with villages which were later recorded in Domesday Book. It was a period of winning from the forest, of settlement, and of organised farming.

Domesday Book includes a remarkably comprehensive survey of the land initiated by King William to ensure accurate assessment and punctual payment of tax. The prosperity of each manor depended upon the amount of land which could be ploughed; in essence, upon the strength of its oxen. Plough-teams were in their turn dependent upon an adequate supply of meadow hay for the winter and so large fertile meadows were the key to the farming economy of those days. This is seen in the relative value per acre of meadow land compared with arable, the former often being worth four times as much as the latter. The value of enclosed pasture was usually less than that of meadow land, while the common pasture land in many instances surrounded the village and gradually merged into scrub and woodland which served as a line of demarcation between neighbouring villages. The scarcity of good pasture is a constant theme of all manorial documents of the period.

Reclamation was continued until around A.D. 1500. The twelfth and thirteenth centuries were the period of greatest colonising activity in England, but this colonisation drive was largely over by about A.D. 1300. Pressure of population seems to have kept peasant demand for land at a high level up to the Black Death in A.D. 1349 although there was considerable contraction of the arable, and hence an increase in grassland, on many estates before A.D. 1300 or very soon afterwards. The Black Death resulted in the death of large numbers of labourers and hence wages rose and the landlords were unable to get their fields cultivated and in spite of legislative measures to resolve the problem a good deal of land simply reverted to grass. This contraction of the arable acreage continued through the late fourteenth century and the first half of the fifteenth. With the break-up of the manorial system a gradual consolidation of holdings took place mainly by exchange. Then too, the trend from a two field system of farming—one field under crop while one lay fallow—towards a three-course system of two fields under crop and one fallow became evident. Ultimately this system gave way to the four course system whereby grass appeared in the open fields which had hitherto been exclusively arable.

The Tudor period was marked by a spate of writings from farmers and historians, and such names as Fitzherbert, Tusser, Leland, Camden and Morden are an essential part of agricultural history. From them a clear picture of the husbandry of the time is obtained and it is quite evident that farmers were becoming very concerned about grass. The meadows of Leicestershire, Northamptonshire, Devon and Somerset brought forth ecstatic praise and it is significant that by A.D. 1600 graziers were obviously men of substance, and wealthy classes of butchers and tanners were arising. The records of the period abound in such cases as the Earl of Derby, whose household in 1590 consumed 56 oxen and 535 sheep, while that of Sir William Fairfax in Yorkshire consumed 49 oxen and 150 sheep, and the household of the Bishop of Aberdeen consumed 48 oxen, 160 sheep, and 17 pigs. Fresh meat in winter was for the wealthy only, for the problem of feeding cattle and sheep on a large scale during the winter months still remained to be solved; the poor, when they had meat in winter, had to make do with salted. England lagged behind the times on this problem, for the value of turnips for cattle during the winter months was already appreciated in the Low Countries.

Wheat as an economic crop offers many attractions to farmers with suitable land and many of the enclosed pastures which had carried cattle and sheep for many years and had as a result increased appreciably in fertility were ploughed, and good yields were obtained which were markedly better than the medieval yield from the open fields, which was recorded as being a meagre 10 bushels per acre. A statute of 1597 had given official recognition to the fact that worn-out arable land regained its fertility when it was laid down to pasture and devoted to grazing stock for a number of years.

We do not know exactly when grass and clover became regarded as a crop and part of a recognised rotation. Richard Weston, a refugee from the Civil War, brought back from Holland a bag of red clover seed when he returned to England. The Spaniards had initiated the Dutch into the growing of red clover (Trifolium pratense) a century before and it was usually sown as a pure crop in the arable rotation. In 1653, Andrew Tarranton wrote The Great Improvement of Lands by Clover and, following much of the advice of Weston and Blyth, gave practical demonstrations of its value for stock feed, either when grazed or made into hay. He also managed to convey something of the fertility-restoring powers of clover and the immense increase in the stock-carrying capacity of clover pastures compared with ordinary grass. He instanced the need for careful control of the grazing to avoid the distressing trouble of “bloat” or “hoven” in which affected animals became “blown up” due to an accumulation of gas in the stomach resulting from failure of the mechanism which normally enables relief to be secured by belching. The trouble usually occurs when animals are suddenly introduced to young rich herbage and unfortunately it may prove fatal within an hour or so. (It is interesting to record that some three hundred years later we have not yet found a wholly reliable remedy.) Finally, he encouraged other farmers to visit him and see his ideas put into practice, and to-day we are broadly speaking still following the technique which he practised.

Progress was slow and more than a hundred years elapsed before the first stages in ley farming were generally adopted. The Society for the Encouragement of the Arts, Manufactures and Commerce did much to encourage land improvement and indeed in 1763 imported the seed of cocksfoot (Dactylis glomerata) from Virginia and also offered awards for the best herbage seed crops grown in this country. Benjamin Stillingfleet, in his Calendar of Flora 1762, invented English (as opposed to Latin) names for such species as had not already acquired them. Unfortunately, he included sweet vernal (Anthoxanthum odoratum) and other useless grasses amongst those recommended as valuable for agricultural purposes. This error was still unnoted 150 years later when excellent samples of this weed were offered for sale as a useful “bottom grass” by the agricultural merchants of the day.

The saving of good seed each year has been stressed by agricultural writers from earliest times. In the eighteenth century Coke of Norfolk and the Duke of Bedford employed children to go into the fields and hedgerows and collect the seed heads of different grasses when they were ripe, in order to have available a store of seed for sowing the following year.

During the latter half of the eighteenth century, agricultural progress was rapid. Tillage methods underwent revolutionary changes, substantial sums of money were invested in farm implements and machinery, in drainage and buildings, and every effort was made to improve both crops and livestock. Agricultural Societies were established all over the country and many of these are still in existence.

After the Napoleonic wars agriculture went into decline. The Board of Agriculture was dissolved in 1822.

When the virgin and fertile lands of the New World came into full production, causing a fall in world grain prices, the British farmer had to face a very real challenge. United Kingdom agriculture turned to dairy farming and animal husbandry generally. A good deal of land was allowed to revert to grass, buildings were not maintained, drainage was neglected, and sheep and cattle as alternative sources of income took the place of corn. By 1874, a vast acreage of arable land had been sown down to grass, no less than 1,688,487 acres between 1877 and 1884. Agriculturists were greatly concerned with the sowing down of land to permanent pasture and so we have J. Caird in his English Agriculture (1850) and M. H. Sutton (Laying Down Land to Permanent Pasture, 1861), J. Howard (Laying Down Land to Grass, 1880), C. de L. Faunce-De Laune (On Laying Land to Permanent Grass, 1882) and William Carruthers (On Laying Land to Permanent Grass, 1883) all in the Journal of the Royal Agricultural Society, devoting much attention to the problem but indicating at the same time that the tide would turn, that permanent grassland would again be ploughed for cropping and that the crops would be the better if good grassland had been established. The whole matter was summarised very effectively in Robert H. Elliott’s book The Clifton Park System of Farming (1898).

In 1889 the Board of Agriculture was re-established, and in 1896, the classical experiments at Cockle Park, Northumberland, were initiated to demonstrate the value of basic slag as a source of phosphoric acid for the grass sward. Basic slag, superphosphate, and combinations of lime, slag, potash and nitrate of soda were under trial, the merit of the fertiliser being assessed by the liveweight increase of sheep which grazed the plots, or by the weight of hay. The outstanding treatment was an application of 10 cwt. per acre of basic slag as a first dressing, followed by 5 cwt. per acre every third year afterwards and this treatment was adopted by large numbers of farmers throughout the country. The effect of the slag was to so encourage the growth of wild white clover that the stock-carrying capacity of the grassland was increased threefold. Even to-day, it is quite common to find farmers using slag in these amounts.

By now attention was being given to the value of native strains of grasses in addition to wild white clover, and work at the North of Scotland College of Agriculture, and by Professor A. N. McAlpine at Glasgow, had indicated something of the potential of grass output when the right types of grasses were linked to wise fertilising. In 1919, Lord Milford, by a generous gift to the University College of Wales at Aberystwyth, brought into being the Welsh Plant Breeding Station which, under its director Professor R. G. Stapledon, was to make a far-reaching contribution to the realm of grassland husbandry in the production of leafy, indigenous strains of the principal grasses. Their names to-day carry the prefix “S” and are known throughout the world.

Other land-marks in the history of grassland in this country are the establishment of Jealott’s Hill Research Station in Berkshire by Imperial Chemical Industries in 1936, the formation of the British Grassland Society in 1945, and the opening of the Grassland Research Institute at Hurley in Berkshire in 1949, the first station to be devoted solely to fundamental research problems in the sphere of grassland husbandry.

Spectacular progress has been made in British agriculture during the past quarter-century. It has become much more productive, has reached a high level of technical efficiency and is probably the most highly mechanised in the world. The acute dangers of two world wars and their aftermath have indicated the vital national need to reduce the dependence of a very large industrial population upon imported food supplies.

The need for maximum self-sufficiency in terms of home-grown feeding-stuffs has placed greater and greater emphasis on the production of more and better grass and upon its more efficient utilisation by grazing and conservation. A greater cattle population has thus been maintained at a higher level of output of both milk and beef, and there has been a marked revival in the sheep industry.

CHAPTER 3 THE GRASS PLANT AND ITS VALUE TO MAN

In this chapter I shall begin with a brief description of the various parts of a grass plant, emphasising the features that are of importance to agriculture. A fuller and more detailed account may be found in Dr. Hubbard’s excellent Penguin volume Grasses (1954).

To the non-botanist all grasses look very much like one another at first sight. On closer inspection, however, differences in habit and form of growth and particularly of inflorescence are very apparent. There are grasses which are Lilliputian in size, contrasting violently with the largest members of the family, the bamboos, bearing great masses of blooms on spikes or panicles a foot or more long. Grasses, too, display an immense capacity for adapting themselves to their environment, some making their home in water or along the banks of streams and rivers, while others survive the scorching heat of the desert and or the intense cold of the polar regions. Some grasses are annual and complete their life cycle in one year, such as the very common annual meadow grass (Poa annua). Others like the soft brome grass (Bromus mollis) are biennial, the seed germinating in late summer or autumn and the plant flowering and seeding the following year. Finally, there are vast numbers of perennials, like perennial ryegrass (Lolium perenne) and couch grass (Agropyron repens), which are potentially immortal, producing new shoots or new lengths of rhizomes for ever if conditions allow. A bamboo may survive for thirty or forty years or even longer. Unlike the annuals and biennials, which bear flower-heads on all or most of the shoots, in the perennials the flowering shoots are accompanied by vegetative shoots, the number of which depends upon the duration of the grass.

These vegetative and flowering shoots are not different in origin. Both shoots start off as a vegetative structure—a very short-jointed stem bearing two ranks of leaves, one leaf at each of its closely-spaced joints or nodes and arranged alternately along the stem, which is constantly producing new leaves at its tip; thus there is a continuous sequence of growth. As each leaf reaches full size the older ones die away, to be replaced by fresh leaves. Meanwhile the stem remains extremely short, but branching often takes place. Buds in the axils of the leaves grow out to form a new short-stemmed leafy shoot, and these in turn produce further shoots in the axils of their leaves, so that a dense tuft is quickly built up. This process of increase in the number of shoots, without any marked lengthening of the stem, is particularly noticeable in young cereal plants during the first few months of growth, and has been given the special name of “tillering,” each shoot being referred to as a “tiller.” Obviously tillering capacity in the cereals means that less seed per acre needs to be sown than would be the case were only a single shoot formed from each seed. If each tiller produced an ear to be harvested flowering would be spread over a long period, hence ripening would be very uneven and farming operations complicated; but the normal wheat-field is sown thickly so that only one or two of the earliest-formed tillers on each plant are able to flower, which ensures that all the ears of grain are ready for cutting at the same time. Pastures, on the other hand, produce more stock food since the grasses cover the ground more rapidly to form a sward or turf, and recover from mechanical damage comparatively quickly because of this characteristic.

A turf of vegetative shoots may be a foot or more in height, but it consists almost entirely of leaf. The stems are still extremely short and completely hidden, so that in a typically tufted grass at this stage of growth all the stems and buds are within about half an inch of the ground. It is only in exceptionally tall-growing grasses, such as the bamboos, that long, upright vegetative stems are produced at an early stage. In the case of creeping grasses there may be some elongated stems but these are horizontally directed and spread along or through the ground as stolons or rhizomes. By way of contrast, the lower internodes of some grasses may become swollen with plant food, and these grasses are known as “bulbous.”

This characteristic of the grasses—the growth-buds remaining close to the ground—determines their value as food for grazing animals. If an upright-growing plant, like kale or a young tree seedling, is grazed off to within an inch or two of the ground it will have lost the greater part of its stem, together with its apical bud and most of its axillary buds. It may recover by the development of new shoots from the base of the stem, but it is unlikely to survive many such grazings. In marked contrast to this a vegetative grass plant grazed

in this way suffers very much less damage. It is clear that unless the grazing is exceptionally close as a result of many animal mouths to the acre or continuous stocking, only the leaves will be removed and all the stems and buds will be left intact and able to continue their growth with comparatively little check. Grasses can therefore withstand repeated grazing and treading by stock. In the face of such grazing, grasses obviously have a great advantage over other taller-growing plants; indeed, except where drought or extreme exposure prevents the growth of taller plants, grassland exists mainly because of grazing. If there were no grazing animals there would be, in a climate like that of Britain, very little grassland, only scrub and forest.