IRRIGATION. 



The upper part of these beds is quite 

 level from end to end, and here the 

 channel, or float, which brings the 

 water on, is cut. From the edge of 

 this channel the ground is made to 

 slope a foot or two on both sides, and 

 a ditch is cut at th(! bottom, parallel 

 to the float (Fi-r. 3). The whole of 

 the ground is laid out in these beds. 

 All the floats are su|)plicd by a main 

 channel, at right angles to the beds, 

 and somewhat above them, and all 

 the ditches or drains run into a main 

 ditch, parallel to the main float, and 

 below the lowest drain. The course 

 of the water is very regular. As soon 

 as the flood-gates are opened, it flows 

 into all the upper channels, which it 

 fills till they overflow in their whole 

 length. The sloping sides are cov- 

 ered with a thin sheet of running wa- 

 ter, which the lower drains collect, 

 and carry into the main ditch. The 

 upper drains should be puddled, to 

 hinder the water from sinking. 



" Experience has shown that there 

 are particular seasons when the wa- 

 ter has the best efTect ; a perfect 

 command of it is, therefore, indispen- 

 sable, and also a regular supply. Du- 

 ring mild frost, when all dry mead- 

 ows are in a state of torpor, and the 

 vegetation is suspended, the water 

 meadows, having a current of water 

 continually flowing over them, are 

 protected from the eflfect of frost, and 

 the grass will continue to grow as 

 long as the water flows over it. Too 

 much moisture, however, would be 

 injurious, and the meadows are 

 therefore laid dry by shutting the 

 flood-gates whenever the tempera- 

 ture of the air is above freezing. By 

 this management the grass grows 

 rapidly at the first sign of spring. 

 Before the dry upland meadows have 

 recovered the efTecte of frost and be- 

 gun to vegetate, the herbage of the 

 water meadows is already luxuriant, 

 the effect being due to the tempera- 

 ture of the water, which must be 

 above that of freezing. As soon as 

 they are fed off or cut for the first 

 crop of hay, the water is immediate- 

 ly put on again, but for a shorter 

 time ; for the warmer the air, the 

 438 



less time will the grass bear to be 

 covered with water. A renewed 

 growth soon appears, and the grass 

 is ready to be cut a second time when 

 the dry meadows only give their first 

 crop. Thus, by judicious manage- 

 ment, three or four crops of grass are 

 obtained in each season, or only one 

 abundant crop is made into hay, and 

 the sheep and cattle feed off the oth- 

 ers. The early grass may be fed till 

 the end of April. A short flooding 

 soon reproduces a crop, which is 

 mowed for hay in June ; another 

 flooding gives an abundant after-math, 

 which is either mowed for hay, or 

 fed off by cows, bullocks, and l^rses ; 

 for at this time the sheep, if pastured 

 in water meadows, are very subject 

 to the rot. The value of good water 

 meadows could scarcely be believed 

 by those who are not familiar with 

 them. Where the water is suited to 

 irrigation, they never require manu- 

 ring. The fertility is kept up contin- 

 ually, and the only attention required 

 is to weed out coarse aquatic plants, 

 which are neither nutritious nor 

 wholesome in hay or pasture. 



" The best soil for a water mead- 

 ow is a good gravel. The finest wa- 

 ter meadows on the Avon, in Wilt- 

 shire, where the richest herbage is 

 found, have scarcely any soil at all, 

 but are on a bed of shingle and peb- 

 bles, matted together by the roots of 

 the grass ; which proves to demon- 

 stration tliat the waters of the Avon 

 contain all the principles essential to 

 rapid vegetation. Great attention is 

 required, and some experience, to 

 irrigate meadows so as to give the 

 greatest profit. 



" In hot weather, when we should 

 imagine that the land must be thirsty, 

 and that too much water cannot be 

 poured over it, much mischief may 

 be done by injudicious flooding. In 

 winter, on the contrary, the land may 

 be covered with water for weeks 

 without injury ; and if an earthy de- 

 posite takes place, the subsequent fer- 

 tility is greatly increased. But this 

 is not properly irrigation ; it is inun- 

 dation ; and the effects depend on 

 entirely different causes. When low 



