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Chapter 9
Pioneer CropsA pioneer crop may be defined as one that is pre-eminently suitable as a first crop to be used on derelict land with a view to paving the way to bringing such land into a condition capable of sustained and profitable crop production. In the choice of a pioneer crop we are, therefore, not primarily concerned with its immediate yield or earning capacity; our chief interest is in the winning of land for future productiveness, although if a pioneer crop can contribute materially to stock feed or direct human food, that at the present time is an important additional advantage. Broadly speaking, pioneer crops are of three types, and operate in three different ways. We have:
- Crops which are comparatively safe to grow and which, because of the methods necessary to prepare the land for their successful reception, entail a considerable amount of preliminary cultivation, and therefore, no mean breaking down of the pre-existing plant cover and sod. Such crops are -- each to its own conditions -- the potato, and wheat, and, although to a lesser extent, beans and kale.
- Leguminous crops in general: crops which, in virtue of their direct influence on soil fertility, and in many cases in virtue also of their deeply penetrating root systems, and of their ability to produce nutritious eatables palatable to stock, are invaluable aids to breaking in derelict acres. In this country, the most important pioneer legumes are lucerne, lupins, red clover, white clover and trefoil.
- Crops which rapidly produce an abundance of feed for stock and which, with the help of adequate manuring, can be established with reasonable certainty under exceedingly adverse conditions. Such crops are rape, hardy green turnips, yellow turnips, Italian ryegrass and, under conditions of extreme poverty, ribgrass and Yorkshire fog.
The function of pioneer crops such as these is to hold stock to the ground in the greatest possible numbers when, as the result of the urination and dunging, the soil will be greatly enriched and the old mat, turf and sod will be rapidly rotted down. Legumes which are grazed off and which rapidly produce a bite, e.g. trefoil, also come under this category, and are, therefore, of a double usefulness.
In my (R.G.S.) earlier writings I have usually only included this class of crop in the pioneer category, and have thus used the word pioneer in a somewhat restricted sense. In the present chapter we shall devote most attention to these stock-holding crops, but it will be to the point first to deal briefly with wheat, the potato and the legumes.Wheat as a Pioneer Crop
There is no doubt that winter wheat is a very safe crop to grow on a wide range of derelict lands as exampled by the Lias and other clays of the Midlands and East, provided:
(a) that reclaiming cultivations are started early enough -- not later than the middle of July -- and are thorough enough;
(b) that the wheat is drilled by about the middle of October;
(c) that the crop is helped by soluble nitrogenous fertilizers as may be necessary, and
(d) that consolidation is safeguarded after frosts are over by rolling and/or by judicious grazing with sheep.
Very tough old sod or land in low thorn or bramble will stand several diskings and/or cultivations or a couple of ploughings and still give an abundantly rough and lumpy tilth for wheat. Almost everywhere up and down the country and perhaps particularly on the heavy clays, we see the best wheat crops on old sod that was broken before the middle of July and subsequently further cultivated -- in marked contrast to innumerable failures on land ploughed too late or hardly cultivated at all. The question of the more suitable varieties for using as a pioneer crop will be touched upon in a later cbapter.
The Potato as a Pioneer Crop
The potato can most usefully be employed as a pioneer crop:
(a) on certain alluvial meadows where the soil is of semi-peaty nature and where the vegetation has been allowed to become coarse and rank, and
(b) where bracken luxuriates on land that is not too steep or too rocky to plough and where there is also a good depth of soil.
Alluvial Meadows
There is much riverside meadow land where the pastures have been allowed greatly to deteriorate, and which are not liable to summer flooding. The most thoroughgoing method of improving such meadows is to plough them up and regrass them: this may be done by direct reseeding or by adopting some preliminary cropping before regrassing. Much of this type of land is very suitable for the growing of potatoes while the thorough cultivations demanded by the potato would form an admirable preparation for regrassing. The swards should be grazed as hard as possible during the summer preceding ploughing, and, if necessary, cut over once or twice with the mowing machine. They should also be roughed over two or three times with the pitchpole harrow. The sod should be heavily predisked in September and the disked surface ploughed-in during October, when, in the following spring, further cultivations would bring the land into a suitable condition for planting potatoes. The acreage of land of this sort is of local occurrence, but, in the aggregate, is large. Typical examples are to be found in the valleys of the Kennet in Berkshire, the Avon, and Itchen in Hampshire, the Frome and Puddle in Dorset and on derelict water-meadows in many of the chalk valleys of southern England and in East Anglia. There are many other areas, including land of a peaty nature such as the moors of central Shropshire. The aggregate acreage of permanent grassland, situated on alluvial meadows in England and Wales (1938) was nearly 400,000 acres; the greater part of this acreage is in an easily ploughable condition.
Bracken Land
We have estimated that just before the war there were some 406,000 acres of more or less densely bracken-clad land in England and Wales. Bracken nowhere advances to elevations much above the plough-line, but much of it is on land too steep or too rocky to plough. Of the total acreage shown by our survey, probably something over 100,000 acres was on land in the "ploughable and ought-to-be-ploughed category"; in short, occupied land, that, apart altogether from potentialities for crop production, should be in highly productive sward.
As a crisis measure, we would not advocate bothering much with the non-ploughable bracken land, but where such land can be ploughed, it should be tackled in a thoroughgoing manner, the ultimate aim being grass, the immediate aim on suitable areas being crops. Dense bracken is not associated with any densely matted sod, but by virtue of the abundance of deeply penetrating rhizomes, it is associated with a friable soil easily to be worked into a suitable condition for the planting of potatoes.
The best way to deal with bracken is to plough it in when it is at full vigour in July. To do this properly would necessitate the tractor and a high-clearance digger plough of the 'Junotrac' or 'Prairie Buster' type. Bracken land ploughed in July could be sown with rape, hardy green turnips and Italian ryegrass in order to provide back-end and winter grazing and reploughed in the following spring in preparation for potatoes. Ploughing in August is nearly as destructive to bracken as ploughing in July, and as a straight preparation for potatoes without any preliminary catch-cropping, it is far better to start operations in August than to defer them until later in the year or until the following spring; dense bracken land is of no value at any time of the year, so that a period in fallow is neither here nor there.
Normally the potato is not a crop in need of lime; most bracken land, however, occurs on acidic soils with a pronounced lime requirement, and under such conditions it is necessary to apply lime in generous amount. It is probable that the chief beneficial effect of the lime for the potato crop is to hasten the decay of the rhizomes and of the attendant vegetation.The Pioneer Legumes
We will deal separately with lucerne and lupins, each of which has a special use, and then with the clovers.
Lucerne
Land that has been in a good lucerne ley will have been greatly enriched, and should be in a good condition for the subsequent production of cereals and other crops. The disadvantage of lucerne as a pioneer crop is that to be of full value as a fodder crop and as a pioneer, it should hold the land for at least four years. Since lucerne is itself so valuable, and such an excellent insurance against drought, even to-day when cereals are a prime need, its use as a pioneer crop should not be debarred, and particularly in districts suitable to it and where the acreage out of heart is very great. Mr. A. W. Oldershaw has used lucerne as a pioneer on the heavy lands of Suffolk to great advantage. He would break up a rubbishy field on such land during the summer, mole-drain, if necessary, and apply lime and fallow until the following spring, when he would sow lucerne under a thin seeding of oats or barley. To fallow and thoroughly clean is a necessity, for lucerne is decidedly weed-shy. To ensure a good stand of lucerne it is necessary to apply phosphates in generous amount. Given proper cleaning operations, lime where necessary and abundant phosphates, there can be no doubt that lucerne is an admirable crop with which to rejuvenate a great deal of the plough-sick land on arable and grass-arable farms, and particularly on such as maintain dairy herds, and where silage is in ever-increasing demand. The seed of lucerne should always be inoculated, and particularly when sown on fields where it has not been previously grown.
Lupins
The lupin has been used extensively in Germany and Holland as a pioneer crop to prepare for subsequent cropping. In Western Australia, too, lupins have proved very satisfactory pioneers in the winning of new agricultural lands. Lupins are probably the only leguminous crop which will thrive on light land poor in lime. The blue variety is the one most commonly grown in this country, and the seed can be saved under the climatic conditions of the eastern counties. If used for folding, care is necessary, because of the presence of a certain amount of poison, but the danger can be reduced by sowing with the lupins a little buckwheat or rape or a few tares and oats. Lupins may be used for green manure, and make an excellent preparation for other crops: a rotation of lupins and rye can be grown almost indefinitely on very light land poor in lime. When the land has been improved by the ploughing-in of a crop or two of lupins, the rotation may be extended to lupins (ploughed-in green, or folded with sheep with necessary precautions): Rye: Potatoes: Oats. There is no doubt that much poor sandy soil in the east of England could be reclaimed by the judicious and informed use of lupins.
The Clovers
On calcareous soils, trefoil (Medicago lupulina and not a true clover) is capable of making very rapid growth, and when well supported by phosphates can be used as a valuable pioneer crop. Sown with Italian ryegrass, it makes an excellent one-year grazing ley, capable of holding a large head of sheep, and therefore assisting to rot down an old sod upon which it may have been sown. A quick-growing white clover like S. 100 will come away rapidly on damper situations and in wetter seasons will provide an immense amount of leafage. A two-year grazing ley based on S. 100, and heavily grazed by sheep and well supported by phosphates, can be used as the pioneer on many classes of poor sod. The clover should be supported by a small sowing of Italian ryegrass, and a certain amount of perennial ryegrass; or on peat and on wetter situations in general, by Aberystwyth S. 48 timothy.
Although crimson clover is a valuable catch crop on well-cultivated land and is the quickest clover to come away, owing to its excessive hairiness it is not a very good grazing plant (it is generally cut green and used as horse-feed or sown with Italian ryegrass and cut for hay) and it is also uncertain of establishment on poor derelict lands and, consequently, it is not to be regarded as a pioneer legume.
Broad red clover and late-flowering red clover can both be used as pioneers when included respectively in one- or two-year grazing leys. It is unfortunate that the seed of subterranean clover is not available in this country at a cheap price. As a pioneer crop, it has been responsible for the complete transformation of enormous acreages in Australia and New Zealand. In this country it has not the same capacity for usefulness, because the conditions are not so favourable for continuous re-establishment from self-sown seed. Sown in July, however, it throws an immense amount of clovery leafage for sheep-feed during the autumn and back end, and therefore would serve as an admirable pioneer crop and, given abundant phosphates, it would so serve under a wide range of conditions.Pioneer Mixtures of Crucifers and Other Plants
These pioneer mixtures are applicable to the poorest and roughest of grazings: the thesis is this: to achieve as rapidly as possible a heavy crop of green eatables, and these to be returned to the soil via the grazing animal. The heavier and the longer-continued the growth, the heavier the dressing of animal residues, and by that much more quickly and effectively will the old and matted sod be rotted down. Pioneer crops are essentially a means to an end -- fertility and ploughability. It is absolutely essential, before embarking upon reclamation via pioneer crops of the sort we are now discussing, to have limed adequately: it is also essential to be generous with nitrogen (nitro-chalk or ammonium sulphate) -- the more nitrogen, the heavier the crop, and the heavier the crop the more animal residues and the quicker the rotting-down of the old mat. It is necessary to support pioneer crops with phosphates, but if the land has been well limed and if a soluble nitrogenous fertilizer is generously employed, then the dressing of phosphate need not be heavy, and it would be reasonably safe even on land markedly deficient in phosphates to use as little as the equivalent of 2-4 cwt. of high grade basic slag.
The chief pioneer crucifers are rape, hardy green turnips and yellow turnips. Of these, rape requires a higher degree of fertility than hardy greens or yellow turnips. Thus, on nearly all situations -- all necessarily poor -- where pioneer mixtures are called for as the first crop, rape should be sown in conjunction with hardy greens. Where the soil is excessively poor, reliance should be placed wholely on hardy greens and yellow turnips.
In order to lengthen the grazing period, a longer-duration grazing plant should always be sown along with the crucifers. On the somewhat better situations, Italian ryegrass admirably meets the case: as conditions become less favourable, ribgrass should be brought to the support of the Italian, and at the highest elevations and on the poorest soils Yorkshire fog should take the place of Italian ryegrass. Thus, high up on the Welsh hills we have employed a mixture consisting only of Yorkshire fog, ribgrass and hardy greens, on which mixture we have successfully fattened lambs. The quotation that follows is appropriate in this place.
'The influence of a succession of pioneer crops on energy-potential is well shown by figures obtained from the most difficult area yet undertaken on the lands of the Cahn Hill Improvement Scheme. The land in question stood at from 1,200 ft. to 1,300 ft. above sea-level, and the vegetation consisted of virgin heather (stunted), bilberry (stunted), Nardus, sheep's fescue and a little Agrostis. After ploughing and slagging, three pioneer crops were taken in succession: the second was sown on the heavily dragged and harrowed 'stubble' of the first, and the third after a second ploughing and a second phosphating. In the first two cases, the crop consisted of hardy green turnip and Yorkshire fog, and in the third, in effect, of hardy green turnip, rape and Italian ryegrass (actually the hardy greens and rape were sown with a general seeds mixture which included Italian ryegrass).
'Data are not available for the full grazing from the three crops respectively, but were obtained in respect of the lambs fattened in the back-end. The results are as follows:
- Live weight increase
in lb. per acreFirst crop -- the crucifers almost a complete failure 16 Second crop -- the crucifers not half of a crop 40 Third crop -- the crucifers a really good crop 126 From which will be seen the really remarkable influence of pioneer crops used in succession as a means of building up energy-potential under the poorest possible of conditions.'
Pioneer crops -- rape and Italian ryegrass in this case -- have been employed with great success for some years on thin and derelict downland by Mr. Hosier, and he has fed the crops off by dairy cows operating from bails. In some cases, the pioneer crops on the Downs have been followed directly by a cereal crop, and in others by a ley. There is undoubtedly the greatest possible scope for the use of pioneer crops on thin, chalky and calcareous soils over a very wide range of country stretching through the Chilterns, the Downs and the Cotswolds.
One of the most essential places for pioneer crops is in our hilly districts of high rainfall, and we would have literally thousands upon thousands of acres at elevations of from about 700 ft. to about 1,150 ft. (according to district and aspect) shared between direct reseeding and pioneer crops -- a pioneer crop can usefully follow a pioneer crop and can be followed in some cases by oats (if areas are fenced) and, more usually, by seeding out. We have to consider not only the summering of lowland cattle in the need of keep and the calls for crop production and silage making on a grand scale in the lowlands, but equally the fate of the draft ewes, the cull ewes, the cull lambs and the wether lambs from our hill flocks. It is a matter of the first importance to maintain our mountain flocks and to ensure that all the progeny of these lead to their full and proper quota of butcher's meat, and this despite the innumerable preoccupations rightly superimposed upon the lowland farmer proper. Our lands above about 650 or 700 ft. could take care of the whole flocks and their offspring, save perhaps the best of the draft ewes, if we would set about reseeding and pioneering on a sufficiently all-embracing scale, and if the lands so conditioned could be used on a communal basis. The matter is one demanding goodwill perhaps more than anything else. All the ploughings, cultivations, limings, manurings and seedings could be conducted in great blocks of country often running into several hundreds of acres together, and consequently should not present insuperable difficulties in the matter of organization and supervision. Here, then, is a concrete example of our point made earlier in this book. If we are to do anything approaching what is possible towards food production, where and when necessary we must be prepared to work in units not of the single farm, but of whole parishes or districts. If we merely endeavour to tackle outrun hill lands in terms of individual farms we shall, at the best, be bringing tens of acres into usefulness, while if the Agricultural Executive Committees themselves would tackle such lands in terms of large units, then we could bring not tens but literally tens of thousands of acres into usefulness, and with an altogether greater assurance of success.
To start with pioneer crops on poor land has the inestimable advantage that it is not necessary (in many districts) to plough before April, or even May, and thus to tackle such poor lands on the pioneering basis affords an opportunity for keeping tractors fully at work when otherwise (in such districts) they would probably be idle. A further advantage is that the whole operation of ploughing, cultivating, liming, manuring and sowing can be conducted as one continuous job from start to finish: of itself supremely economic of man- and tractor-hours.General Considerations
No distinction or definition can be absolutely clear-cut when dealing with matters agricultural. Pioneer crops of the crucifer-Italian ryegrass type merge into one- or two-year leys, which latter, as we have said, can be very usefully employed as pioneer crops. Thus, to directly reseed in terms of a short ley in particular is to establish a pioneer crop, and under certain circumstances it is a sound practice to sow the ley mixture, including clovers, under a thin seeding of rape.
Similarly, it would be easy to extend the number of pioneer crops under each of the classifications we have considered. We must remember, however, that by definition a pioneer crop must be able to thrive on derelict land newly broken, and must pave the way to enhanced fertility. Two further crops are deserving of mention, viz., linseed (or flax) and certain types of oat. With proper manuring, linseed could be successfully grown on newly broken sward on land of low fertility, and has a pioneer value because it is a good crop with which to under-sow a clover-containing ley mixture.
We would not regard the ordinary oat as a pioneer crop, but the little brown oat of Wales (the Avena strigosa or Ceirch Llwyd) deserves to be classed with wheat in this class. Not that Ceirch Llwyd demands any special cultivations -- far from it -- but it is an oat which is capable of producing useful yields of grain and straw together from newly broken land in a very low state of fertility. It is a pioneer, therefore, by virtue of the inducement it offers to the farmer to break poor land. Much hill land in Wales has been brought into cultivation by ploughing up virgin heath or moor and sowing Ceirch Llwyd along with a four- to six-year ley mixture. Each year the process is repeated upon a new piece of virgin land, by which means over a number of years considerable reclamations are effected. Where this has been done as a regular and long-continued practice on a single farm, and well supported by phosphates and by wild white clover in the seeds mixture, both the oat crop and the ley are of greatly increased yielding capacity when the areas reclaimed come for their second ploughing and second cropping. Where we have ploughable rough grazing in large amount, the following is, in fact, a very sensible rotation: oats ( =Ceirch Llwyd), grass, grass, grass, grass, grass, grass, oats and back to grass. Under this system, the only crops removed from the land in fourteen years are the two crops of oats, oats which go to the wintering of cattle, which cattle, in turn, graze the hill swards in the summer and add to the benefits initiated by the ploughing. This example of a rather special pioneer crop and of rather special pioneering is given because we feel there is a place for the Avena strigosa outside Wales and the Western Islands of Scotland, and because our hill lands, properly farmed, with the judicious use of the plough, could contribute so very much more to our cattle and sheep populations -- so much more than is at all generally believed to be within the realm of practicability. It is true that shortage of phosphates is to-day (1941) a serious handicap, but we could go a long way by resort only to sufficiently heavy dressings of lime. The question of our hill lands will receive further consideration in the chapter on 'Permanent Grass and Rough Grazings' (Chapter 11).References
OLDERSHAW, A. W. (1941). 'Farming Light Land in War-time.' Journ. Min. Agric. Vol. 47.
STAPLEDON, R. G. (1939). Agriculture in the Twentieth Century. (Essays presented to Sir Daniel Hall.) Clarendon Press, Oxford.
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