Irrigation.
Watering of meadows wasuseclinEng land even in the days of Queen Elizabeth, and was carried on upon a large scale by Rowland Vaughan, in the golden valleyof Herefordshire. He likewise published a treatise on the subject After this Pe riod, and about a century since, it WaS introduced by- Mr. IVelladvise into Glou cestershire, with abundant proofs of its efficacy- and imPortance. So slow, how ever, is the progress of improvement, that it is only of late ,years that this over flowing of g-rounds, in nearly all other situations as well a.s in, level ones, has been brought considerably into use. It is a practice by which, in mild seasons, grass is produced in extreme abundance, even so early as in March; grass, too, particularly nutritious ai well as plen tiful, on. which cattle which hayc 4.; tcred hardly thrive with great rapidity, arid on which young lambs feed with sur prising advantage. Between March and May, the feed of meadows, in consequence of this practice, is estimated at worth one guinea per acre ; after which an acre will yieldtwo tons of hay in June, while the after-math may be valued at twenty shil lings. In consequence of this manage ment, moreover, the land is continually improving in quality, its herbage advan cing in fineness, the soil becoming more firm and sound, and the depth of its mould being augmented. It may be esti mated that in each county in England and Wales two thousand acres may be increas ed in value one pound per acre, by means of irrigation; a national advantage ofseri ous moment, and drawing after it the great improvement of other lands, and the ern ploymentof many honest and industrious poor. The principles on which the prac tice depends have no portion of difficulty and complexity whatever. Water will al way s rise to the level of the receptacle from which it is derived. All streams de scending in a greater or less degree, hich is indicated by their smooth and slow or their agitated and noisy progress, it is obvious that a main or trench may be taken from a river which will convey wa ter over the land by the side of that river to a considerable distance below the head of the main, where the river from which It is taken flows greatly below it. As
water, however, if left to stagnate upon land, does it very considerable injury, instead of benefiting it, by cherishing Hags, rushes, and other weeds, it is requi site to ascertain, before it be introduced upon any spot, that it can be easily and effectually drained off.
The muddiness of the water applied is stated by some to be of little consequence, and several writers have even laid it down as a maxim, that the purer or clearer the water is, the more beneficial are its effects. These opinions, however, appear to be directly contradicted by experience ; and it may be affirmed, that the mud of water, particularly in some situations, is nearly of as much consequence in winter water ing, as dung is in the improvement of a poor upland field. Every meadow will be found pro duct; ve, proportion ally to the quantity of mud collected from the water. Those meadows which lie next below any village or town, are uniformly most rapid and plentiful in their growth. So well known is this truth, that disputes are per petually arisingconcerningthe first appli cation of water to lends; and when mud is supposed to be collected at the bottom of a river, or in ditches, many persons will employ labourers with rakes, for several days together, to disturb it, that it may be carried down by the water, and spread upon the meadows. The moreturbid and feculent the water, the more beneficially it acts. Hasty and violent rains, produ cing floods, dissolve the salts of the cir cumjacent lands, and wash from them con siderable portions of the manure, which naturally or factitiously had been depo sited on them. Water from a spring de pendsin no small degree for the of nutriment it affords to vegetables, on the nature of the strata over which it passes. If these be metallic, or consisting of earth partaking of the sulphuric acid, it may be really injurious. But that which passes over fossil chalks, or any thing of a calcareous nature, will highly promote the process of vegetation. That which has run a long way is, almost always, pre ferable to what flows over land immedi ately from the spring.