30 



On the Deanston frequent Drain System, 



breaks and pulverizes the lower crust without bringing it to the 

 top. This subsoil-plough, such as Mr. Smith has used^ is a 

 heavy implement^ requiring the draught of four, six, or eight 

 horses, according to the tenacity and strength of the substratum. 



Mr. Smith contends that the subsoil, by being moved, becomes 

 pervious both to air and moisture ; that the efficacy of the drains 

 is thus perfected and perpetuated ; and that the character of the 

 subsoil itself, when relieved from superfluous moisture, and open 

 to atmospheric influence, is entirely changed ; that it becomes 

 mellow and friable ; and after one rotation, or a lapse of five years, 

 that it may be brought to the top, by deep ploughing, with safety 

 and propriety, and be mixed with the surface-soil to great 

 advantage. 



In the midland counties of England, deep ploughing after 

 furrow-draining has been the constant practice ; but the use of 

 six horses in a subsoil-plough is a novelty in Scotland. In 

 England a portion of the subsoil is raised at once to the top : at 

 Deanston the subsoil, though broken, is not so raised ; and here 

 the important question arises. When land is effectually Underdrained, 

 which is the right treatment of the subsoil ? Will you bring a 

 portion of it immediately to the surface by deep ploughing, or will 

 you, with Mr. Smith, delay this operation for some years, until the 

 subsoil shall have been mellowed, after having been broken and 

 penetrated by the atmosphere ? 



The advantages of the wide circulation of agricultural know- 

 ledge of the multiplication of experiments, and of the interchange 

 both of theory and practice between Scotland and England, will 

 here develop themselves in the clearest light. Furrow-draining 

 and deep-ploughing have been practised in England for half a 

 century ; yet the introduction of an analogous system into Scotland 

 is regarded almost as a discovery. But in Scotland itself the 

 greatest difference of opinion prevails on the question of turning 

 up or only moving the subsoil after draining. Some of the greatest 

 authorities in East Lothian differ from Mr. Smith, and lean to the 

 English practice. In the first furrow for green crop after draining, 

 by two ploughs following each other, which is equivalent to trench- 

 ploughing, they go down to the depth of 12 or 14 inches, and 

 bring up a certain quantity of virgin soil. 



It is obvious that this difference of practice in the treatment of 

 the subsoil involves a most important question, which can only be 

 solved by accurate and multiplied experiments. The outlay of 

 capital, which is common to both plans, consists in effectual under- 

 draining ; and no subsequent management, no fresh application of 

 capital, can be of any avail, unless, on retentive soils or a substratum 

 of clay, the water be quickly carried off. This I take to be an 

 axiom undisputed in agriculture : but after effectual draining, when 



