THE DRAINAGE OF THE FARM. 



be attended with great advantages. Even pure water is of much value, 

 in conveying the elements of fertility to the roots of plants ; but rain 

 water contains ingredients which make it valuable as a direct fertilizer, 

 hould not be looked upon as a nuisance, therefore, which cannot be 

 too speedily got rid of, but rather as an enricher of the soil, through the 



s of which it ought to percolate slowly, in order that its useful j>; 

 may be completely extracted. There are considerable differences of opi- 

 nion amongst scientific men in regard to the qualities of the various en- 

 riching substances that are usually to be found in rain water ; but all 

 e that it contains some ammonia and nitric acid, as well as other mat- 

 of less practical importance. Now, in a properly drained soil, full 

 advantage is taken of these ingredients, in impregnating the particles, and 

 increasing their effects in promoting the growth of plants. Indeed, tl 

 can be no fertility without rain water ; and its beneficial action upon the 

 soil and subsoil is only to be obtained by systematic drainage. " The 

 introduction of water to a soil," says Liebig, " is, properly speaking, an 

 introduction of alkalies." And so it is; for, on well-drained land, rain 

 water is unquestionably a liquid manure. But it is not merely in its di- 

 rect manurial and decomposing effects on the soil, that we must look on 

 rain water as a valuable fertilizer. It carrries heat into the ground, and 

 thus the land becomes warmer and earlier than it was before. It also 

 washes out noxious substances, and carries them into the drain-channels) 

 or leaves them harmless in the ground. 



The power of soils to absorb moisture, in the form of dew or aqueous 



vapour, is greatly increased by a complete system of under-drainage beiii- 



out. And there can be no question whatever, that the land which 



rbs most moisture from the atmosphere, is usually the best ada; 



for the production of crops. " The power of soils to absorb water from 



says Sir Humphrey Davy, "is much connected with fertil 

 M this power is great, the plant is supplied with moist uiv in dry 



:d the effect of evaporation in the day is counteracted by the ab- 

 sorption of aque -iir from the atmosphere, by the interior parts of 



during the day, and by both tin; exterior and interior durin- 

 niirht." It is Only these soils, of course, that an- finely comminuted to a 

 able d-pth, that absorb the ]ar_ f '^t .jiiantity of moisture : and h< 



. for under-draining bi-in^ follow, -d up by I id thorough 



m of cultivation. 



We see,theivf, ,re, that, in inquiring what drainage really is, we discover 

 >n upon the soil, calculated to remove superfluous 

 depth of the ^ratimi in which the roots of cultivated pi : 



