TREATMENT OF GRASS LANDS. 227 



drains, which take tho water from its natural channel, keeping 

 a constant flow without allowing it to accumulate in any part. 



The process of surface irrigation is not so simple as many 

 would suppose. It requires considerable skill and practice, and 

 many fiiilures have followed experiments of this kind, made 

 without due care and attention. Sir John Sinclair, however, 

 in speaking of this operation calls it one of the " easiest, cheap- 

 est and most certain modes of improving poor land in particu- 

 lar, if it is of a dry and gravelly nature. Land when once 

 improved by irrigation is put into a state of perpetual fertility, 

 without any occasion for manure or trouble of weeding, or any 

 other material expense ; it becomes so productive as to yield 

 the largest bulk of hay, besides abundance of the very best 

 support for ewes and lambs in the spring, and for cows and other 

 cattle in the autumn of every year. In favorable situations it 

 produces very early grass in the spring, when it is doubly valu- 

 able ; and not only is the land thus rendered fertile without 

 any occasion for manure, but it produces food for animals, 

 which is converted into manure to be used on other lands, thus 

 augmenting that great source of fertility." 



The effect and value of irrigation does not depend altogether 

 upon the artificial supply of moisture which it furnishes to the 

 plant. " The mechanical action of the irrigatory current of 

 water, in exercising the plants, strengthening their organisms, 

 keeping their stems and root crowns clear of obstruction, pro- 

 moting the equable circulation of water and oxygen around 

 them, and causing an equable distribution of the soluble mate- 

 rials' of their food, probably plays a considerable part in irriga- 

 tory fertilization. The differences of effect, from the mere 

 circumstance of flowing or stagnation of the water, are pro- 

 digious ; for while flowing water coaxes up the finest indigenous 

 grasses of the climate, and renders them sweet and wholesome, 

 and nutritious, and luxuriant, stagnant water starves, deterio- 

 rates, or kills all the good grasses." 



The effect which surface irrigation produces on the nutritive 

 qualities of the grasses may be seen by reference to the tables 

 of analyses found in a preceding section. 



This subject ought to receive the careful attention of the enter- 

 prising farmer. Even a farmer of very limited means may do 



