]46 IRRIGATION OF LAND. 



grass grows tlie most rapidlj, and yields imiuense crops by the aid 

 of water, and Mr. Flint states that it will endure any amount of 

 forcing by irrigation." A year should elapse after seeding before 

 •water is applied and the effect is usually slight the first year, but 

 rapidly increases. During each season the channels and ditches 

 should occasionally be looked to, and floating substances, which tend 

 to obstruct the water, removed. 



Several foreign writers (and even one who wrote 2000 years ago,) 

 have given directions as to the management of water meadows, but 

 the two brief and simple rules adopted in France while the crop is 

 growing, are probably well adapted to this country, viz : 



First. Water profusely in nights and cloudy days only. 



Second. Keep the water constantly moving. 



The efToct in that country, under this method, has been pro- 

 nounced wonderful. For three days and nights before cutting the 

 crop, which should be done as soon as mature, the water should be 

 entirely withheld, and let on immediately after the crop is removed, 

 to induce a second crop either for hay or pasturage. 



For summer irrigation, the water should be turned on at the 

 commencement of the spring freshets, and be continued both night 

 and day till the freshets entirely subside, the water of the streams 

 becomes clear and the weather moderate. The night method may then 

 be adopted, and the water wholly withheld when the grass ceases 

 growing in autumn. Winter irrigation, it is said, tends to prevent 

 the ground from freezing, or at least to the depth it otherwise would, 

 and, unlike summer irrigation, is adapted to both level and sloping 

 lands. It is applied to the former when the ground begins to freeze, 

 and is withheld in spring when freezing ceases and the spring fresh- 

 ets subside. A thin sheet of ice is at first formed, which gradually 

 increases and protects the ground under it. Prof. Davy found the 

 earth beneath a sheet of ice, on a water meadow in England, to be 

 fourteen degrees warmer than the atmosphere above. Chaptal, in 

 referring to tiiis circumstance, observes, " that every one must have 

 noticed that when only a part of a meadow is covered with water 

 during winter, the herbage on that part left dry is withered and 

 nearly dead, while the rest retains its green hue, and continues to 

 grow." Tlie recipient of the premium for irrigation above alluded 

 to, states that he considers irrigation in winter equal to that of sum- 



