1902 Encyclopedia > Agriculture > Reclaiming of Fenlands. Blowing Sands.

Agriculture
(Part 96)




XIX. IMPROVEMENT OF WASTELANDS (cont.)

Reclaiming of Fenlands. Blowing Sands.


Reclaiming of Fenlands

We next notice the fen lands of England, "In popular language, the word fen designates all low wet lands, whether peat-bog, river alluvium, or salt marsh; but in the great Bedford level, which, extending itself in Cambridge shire and five adjoining countries, is the largest tract of fen land in the kingdom, the farmer always distinguished, and it is thought conveniently and correctly, between fen land and marsh land. By the former they mean land partly alluvial and formed by river floods, and partly accumulated by the growth of peat. Such lands are almost invariably of a black color, and contain a great percentage of carbon. By marsh lands they mean low tracts gained from the sea, either by the gradual silting up of estuaries or by artificial embankments." Low-lying peat occurs in small patches in nearly every maritime country of Britain, being usually separated from the sea or from estuaries by salt marsh or alluvium. There is large extent of such land in Somerset shire yet but partially drained, and a still larger breadth in Lancashire, where its improvement makes steady progress. In Kent, on the seaboard of Norfolk, on both shores of the Humber, and stretching along the sides of its tributaries, there are immerse tracts of this description of land. But these are all exceeded in importance by the "great level of the fens, which occupies the south-eastern quarter of Lincolnshire, the northern half of Cambridgeshire, and spreads also into the counties of Norfolk, Suffolk, Huntingdon, and Northampton. Its length is about 70 miles, its breath from 3 or 4 to 30 or 40 miles, the whole area being upwards of 1060 square miles, or 680,000 acres. On the map the fends appear like an enlargement of the Wash, and in reality have the aspect of a sea of land, lying between that bay and the high lands in each of the above-named counties, which seem to form an irregular coast-line around it." This fen country has for centuries been the scene of drainage operations on a stupendous scale. The whole surface of the great basin of the fens is lower than the sea, the level varying from four to sixteen feet below high-water mark in the German Ocean. The difficulty of draining this flat tract is increased from the circumstance that the ground is highest near the shore, and falls inland towards the foot of the scope. These inland and lowest grounds consists of spongy peat, which has a natural tendency to retain water. The rivers and streams which flow from the higher inlands discharge upon these level grounds, and originally found their way into the broad and shallow entuary of the Wash, obstructed in all directions by bars and shifting sand-banks. These upland waters being now caught at their point of entrance upon the fens, are confined within strong artificial banks, and so guided straight seaward. They are thus concentration and momentum assist in scouring out the silt from the narrow channel to which they are confined. The tidal waters are at the same time fenced out by sea-banks, which are provided at proper intervals with sluice doors, by which the waters escape at ebb-tie. To show the extent of these operations, it may be mentioned that the whole sea-coast of Lincolnshire and part of Norfolk, a line of at least 130 miles, consists of marsh lands lower than the tides, and is protected by barrier banks, besides which there are hundreds of miles of river embankments. When this does not provide such a drainage as to admit of cultivation, the water is lifted mechanically by wind or stream mills into the main aqueducts.

The first use of stream,-engines for the purpose of draining was in Deeping fen, where, in 1824-5, two, of 80 and 60 horse-power respectively, were erected. By means of these two engines upwards of 20,000 acres have now a good drainage, whereas formerly forty-four wind-mills, with an aggregate power of 400 horses, failed to keep them sufficiently dry. The scoop-wheel of the larger engine is 28 feet in diameter, and the float-boards are 5 feet wide. It was intended to have a "dip" of 5 feet, but the land has subsided so much in consequence of the draining that it seldom has a dip of more than 2 feet 9 inches. The water is lifted on an average 7 feet high. When both engines are at work they raise 300 tons weight of water per minute.





The soil of the fens consists for the most part of dark-colored peat, from 1 to 8 or ten feet in depth. The surface in general is not pure peat, but is mixed with silt or other soil. Under this there is in general a stratum of brown spongy peat, which sometimes rests upon gravel, but for the most part upon clay, which usually contains a portion of calcareous matter, The removal of the water has of course been the primary improvement; but subsidiary to this the rapid amelioration and great fertility of the fen lands are largely due to this fortunate conjunction of clay and peat. The early practice of the fen farmers was to pare and burn the surface, grow repeated crops of rape, oats, wheat, &c., and burn again. The subsidence of the soil subsequent to the draining and repeated paring and burning, brought the surface nearer to the subjacent clay, which the cultivators by and by began to dig up and spread over the surface. This practice is now universal, and its continued use, together with careful cultivation and liberal manuring, has changed a not very productive peat into one of the most fertile soils in the kingdom. Nowhere in our country has the industry and skill of man effected greater changes than in the fens. What was once a dismal morass, presenting to the view in summer a wilderness of reeds, sedges, and pools of water, among which the cattle waded, and in winter almost an unbroken expanse of water, is now a fertile corn land. The fen men, who formerly lived upon the adjacent high lands, and occupied themselves lived fishing, fowling, and attending to their cattle, have now erected homesteads upon the fen lands, divided them by thorn hedges, and brought them into the highest state of cultivation.

We referred at the outset to the distinction betwixt fen land and marsh land. The following pertinent observations on the reclamation of marsh land are extracted from Mr. David Stevenson’s paper in the Highland and Agricultural Society’s Transactions, vol. iii., 1871.

First, In order to insure success, the space to be reclaimed must be within the influence of water containing much alluvial matter and not on the shores of an open sandy estuary.

Secondly, The spaces to be reclaimed should be allowed to receive the deposit left by the tide for as long a period as possible, and no attempt should be made entirely to exclude the water from them, until they have by gradual accretion attain ed the level of at least ordinary spring tides.

The first cast to which I shall refer is Loch Foyle, a situation where the amount of salt water greatly preponderates over the fresh. Extensive reclamations have been made there, and I have received from Mr. G. Henry Wiggins, of Londonderry, some notes regarding them from which I extract the following interesting information: ---

"After the salt water had been excluded, shallow surface drains were made with spades or forks, and in about two years ryegrass grew pretty freely: exceptional spots remained barren for some time. The grass was followed by oats, which improved as the salt left the soil. Deeper draining allowed the cultivation of flax and clover; afterwards, on deeper draining, all ordinary crops began to grow well --- wheat, beans, turnips, mangold, and carrots --- but all requiring fully as much manure as any old upper land. These sloblands, says Mr. Wiggins, yield a great return for manure, but must have manure on the lower and damper portions. Feorin grass grows well without manure.

"Whenever the ditches have so far drained the soil as to allow of its becoming cracked and open to the air, the crops begin to increase in produce, but the full value of the soil is never known until thoroughly under-drained with tile or stone; it then mostly yields excellent crops of almost any produce, clover and ryegrass for hay being perhaps the most profitable. Grazing the land does not answer, except from the beginning of May to the end of September; after this the soil is too cold and damp for the beast to lie down, and they begin to fail."

The expense of these intakes on the Foyle may be taken at about £20 an acre to get them from the sea; the expense of bringing the land when got into cultivation will come to at least £10 more; making a total of £30 per acre. The best lands are worth 50s. to 40s. the Cunningham or Scotch acre, and the lowest and wettest parts perhaps not more than 10s. --- say 30s. round as a fair average. To this has to be added the expenses of keeping up the banks and pumping water; so that I believe Mr. Wiggins is right when he says that no great profit can be expected, and that these matters are generally undertaken by hopeful and energetic enthusiasts, who seldom realize their expectations, and afterwards fall into the hands of other parties, who are perhaps rather more successful.

The reclamations made by the Ulverstin and Lancaster Railway in Morecambe Bay were rapidly formed by the embankment for carrying the railway, which was made in pretty deep water. Like the Foyle, there is also predominance of sea-water. Mr. F. Drewry, of Holker in Lancashire, has favored me with the following information: --- "A portion of the land enclosed by the railway in 1856 was grassed over, and leveled it was divided into fields by open ditches and wire fences; the ditches had to be made very wide at the top, in order to get them to stand. The land was then drained with 3-inch pipes, each drain opening into the ditch at each side of the field. The tiles were all covered round with peat moss, to act as a filter to prevent the sand from running into them. The sand is so fine that without this precaution the drains would have filled up very quickly. The drainage is the great difficulty, as they are very apt to fill up after every precaution has been taken.





"On the portion which was grassed over, two crops of oats were first taken, and then it was green-cropped. It grew for a few years good crops of wheat, beans, and clover, as well as Swedish turnips and mangolds; but though a great quantitiy of manure was used, the crops fell off, and at present it is nearly all in grass. The portion which was bare sand was treated in the same way, except as to the first two crops of oats. It was green-cropped after it had been enclosed about two years. After the railway was made there was no means of silting the land. The tide was entirely kept out; had it ben admitted, this land would have been much more valuable and much higher --- we would then have had a better drainage and a rich sand. That portion which was grassed over at the time it was enclosed is still much the best.

"When land is reclaimed from the sea, the first thing to be looked to is to good outfall for the water, and, when it is possible, no doubt it is very desirable that the land should be silted up gradually. In our case this could nor be done, as the reclamation of the land was a very secondary affair.

In the district called Marshland, in Norfolk, extending between the Ouse and the Nen; in that called South Holland, in Lincolnshire, stretching between the Welland; northward of Spalding, and also north-east of Boston, there is a considerable tract of marine clay soil. In Marshland, this is chiefly arable land, producing large crops of wheat and beans; but in Lincolnshire it forms exceedingly fine grazing land. This tract lies within the old Roman embankment by which the district was first defended from the ocean. Outside this barrier are the proper marsh lands, which have been reclaimed in portions at successive periods, and are still intersected in all directions by ranges of banks. The extraordinary feature of this tract is, that the surface outside the Roman bank is 3 or e feet higher than that in the inside, and the level of each new enclosure is more elevated than the previous one. The land rises step by step as the coast is approached so that the most recently reclaimed land is often 12 or even 18 feet higher than the lowest fen land in the interior, the drainage from which must nevertheless be conveyed through there more elevated marches to the sea.

Land such as some of those which we have just been describing are often greatly improved, or rather may be said to be made, by means of a peculiar made of irrigation called "warping." It is practicable only in the case of land lying before the level of high tide in muddy rivers. It is little more than a century since it was first practiced in England, the first instance of it being near Howden, on the banks of the Humber. But although the practice is comparatively new in Britain, it has long been in use on the continent of Europe, particularly in Italy, and is thus described by Mr. Cadell: --- "In the Val de Chiana, fields that are too low are raised and fertilized by the process called colmata, which is done in the following manner: --- The field is surrounded by an embankment to confine the water. The dike of the rivulet is broken down so as to admit the muddy water of the high floods. The Chiana itself is too powerful a body of water to be used for this purpose; it is only the streams that flow into the Chiana that are thus used. This water is allowed to settle and deposit its mud upon the field. The water is then let off into the river at the lower end of the field by a discharging course called scolo, and in French canal d’ecoulement. The water-course which conducts the water from a river, either to a field for irrigation or to a mill, is called yora. In this manner a field will be raised 5 1/2 and sometimes 7 1/2 feet in ten years. If the dike is broken down to the bottom, the field may be raised to the same height in seven years; but then in this case gravel is also carried in along with the mud. In a field of 25 acres, which has been six years under the process of colmata, in which the dike was broken down to within 3 feet of the bottom, the process was seen to be so far advanced that only another year was requisite for its completion. The floods in this instance had been much charged with soil. The water which comes off cultivated land completes the process sooner than that which comes off hill and woodland. Almost the whole of the Val di Chiana has been raised by the process of colmata." [Footnote 406-1]

Blowing Sands

On many parts of our sea-coasts, and especially in the Hebrides, there occur extensive tracts of blowing sands, which are naturally not only sterile themselves, but a source of danger to better lands adjoining them, which in some instances have been quite ruined by the sand deposited upon them by the winds. This mischief is effectually prevented by a process beautifully simple and useful, namely, planting the sand-banks with sea bent-grass (Arundo arenaria), the matting fibres and stems of which not only bind the sand, but clothe it with a herbage which is relished by cattle, and which, being able to resist the severest winter weather, furnishes a valuable winter forage in those bleak situations. The bent-grass can be propagated by seed, but in exposed situations it is found better to transplant it. This operation is performed betwixt October and March, as it succeeds best when the sand is moist and evaporated slow.


Footnote

406-1 Journey in Carniola, Italy and France, W. A. Cadell, Esq., F.R.S.


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