Page:Encyclopædia Britannica, first edition - Volume I, A-B.pdf/79

 55 A G R r C 1 L T U R E. It is therefore a difficult matter to clear land of bram- ridges into fome other furrow, along which it is carried ble, efpecially when it is ftony; for the bramble puihes off the field. and interweaves its roots among the ftones, which renders There are two kinds of drains, viz. open drains, and it necefi'ary to dig out the ftones before it can be fuffi- hollow drains. Hollow drains differ from open ones, ciently rooted up by ploughing or tearing. How- in being filled with loofe Hones, covered with turff, brufhever, digging out the ftones, and ploughing the land in wood, or ftraw, and a layer of earth thick enough to alfuch a manner as is moft proper for cutting and tearing low a plough to go’eafily through above. Thefe hollow up the roots of bramble, may be the more liifely recom- drains are attended with two advantages; no land is mended, as they at the fame time ferve many other loll by them, and they are no impediment in ploughing. Open drains, however, are in moft cafes preferable to ufeful purpofes. hollow ones: They alone are capable of intercepting 0verflowings from higher grounds, and for carrying off 2. Of Water, as an Impediment to Vege- water that falls in tain. The water in thefe cafes being always on the furface, will run freely over hollow drains, tation. efpecially when fituated on a declivity. But hollow drains Some plants require a greater, and fome a lefler pro- may be ufed with advantage in land wet by fprings ; beportion of water in their food. The plants ufually cul- caufe nothing more is required than to continue the chantivated in our fields are of the latter kind, and are eafi- nels of the water below ground, and not allow it to ly injured by an over-proportion of water. Hence, wa- break out, till it arrives at a place where it can do no ter may be confidered as an impedement to vegetation; harm. and it becomes neceffary to confider the moll proper me- It will not be improper here to mention, that fome foils retain water much longer than others, and confethods of conveying it off the land. quently are more liable to be damaged by water. Soils that have a large proportion of clay, or of mofs, are of Of draining Land. this kind. As thefe foils naturally retain water like a Some lands are wet from their fituation, being expo- ipunge, calling drains, and laying the land up in ridges,, will not convey it away. To drain fuch lands, their nafed to overflowings from higher grounds, and having no ture, and power of retaining water, muft be changed by proper defcent to allow the water to run off. The bottom of fome land is of fuch a nature as to culture. clay-foil can only be drained by frequent ftirring, and force out, in fprings, the water that runs below the fur- theThe face. Springs fometimes bieak out, becaufe the chan- application of fuch manures as raife a fermentation, nels, in which they run, reach the furface; and fome- Thefe operations open the pores of the foil, and thereby times becaufe they are interrupted.in their courfe, which afford a free paflage to the water. The moffy foil, on the other hand, is too open and makes them force their way above ground. The wetnefs of land is fometimes occafioned by vio- porous, but is poffefied of an abforbing quality, by which lent and frequent rains; and.fcmetimes all thefe caufes it retains the water. To drain this foil, it is neceffary to condenfe it, and, if poffible, to deftroy its quality of may concur in rendering land wet.Land that is wet from its fituation may be drained in retaining water. Frequent ftirrings, and fdch manures as this manner : Although the wet land be fo low, as to raife a fermentation, and tend to putrefy the mofs, are render it difficult to carry off die-water; yet the water faid to render it firm and folid, and thereby both premay be intercepted by a-drain, before it reaches the low vent it from receiving fo large a quantity of—water, and deftroy the quality of retaining it. ground. Land, w^et by fprings, lies generally in a Hoping drreftion, which makes it the more eafy to drain. When Of draining Marifbes. the water runs near the furface, before it breaks out, it may be intercepted by a drain* drawn acrofs the decli- The foil of mariffies, being compofed of diffolved vevity, a little above the place where it firft makes its ap- getables, dull blown in by the winds, and earth waffied pearance. But, if the channel lies deep, the drain ffiould down from the high grounds with which they are genebe drawn direttly acrofs where it fprings up. rally furrounded, is light and fpungy, but very rich and But, when the wetnefs of the land is owing to the valuable when drained. climate, or a rainy feafon, the U'ater cannot be inter- In draining a mariffi, all the ftagnating water Ihould rupted by drains • however, obllrudHons may be remo- be firll carried off' by a large open drain, with a fufficient ,ved, fo as to allow the water to run off as quickly as fall, and as deep as the bottom of the mariffi. When poffible. To drain land in this fituation, it is neceffary the ftagnating water is conveyed away, the earth by deto lay it up in ridges properly placed, and to cut fmali grees will fubfide, and become folk!; and £bme land drains acrofs thefe ridges, communicating with each o- will thus be gained on each fide: The bottom likewife ther, and with the furrows. By this method all the foon becomes firm enough to allow the drain to be grafurrow's betwixt the ridges become drains; the water, dually carried forward through the middle of the mariih.' as it falls upon the ridges, immediately makes its way If the fprings, which fupply the water, rife near the to the furrows; and, if it meets with an interruption in middle of the mariffi, tiffs principal drain, with a few any of them, it is conveyed by the drains acrofs the bi .inches on each fide, where the firings are large!! or Von. I. No! 3. 3 O moli