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CHEMISTRY OF AGRICULTURE. 409 



It is not always advisable to double, at once, the depth to 

 which the plough is run, for the reason that the subsoil may 

 not be at once in a condition to benefit the crop ; indeed, in 

 many soils such a course would be decidedly injurious. It is 

 necessary, in many locations, to bring up but a thin layer of 

 the new soil each year ; this is too small in quantity to injure 

 the fertility of the surface soil, and by exposure to the atmos- 

 phere and by the decay of roots and other organic matter, it 

 would become in one year as good as the older earth, allowing 

 a new quantity to be elevated, until, in course of time, the soil 

 should be made sufficiently deep. 



There is a kind of culture, recently introduced under the 

 name of subsoilirig-, which has proved itself one of the greatest 

 improvements ever made in any industrial branch of economy. 

 It consists of passing through the subsoil at a depth of from one 

 to two feet, an implement which merely loosens the mass, 

 without bringing it to the surface. The subsoil plough has 

 been much improved in this country, and the most recent form, 

 which is simply a diamond-shaped foot, attached by two steel 

 or wrought-iron standards, or by a cast-iron plate, to a common 

 plough beam, in such manner that when used the soil is lifted 

 upward and outward, on each side of the line of travel — may 

 be worked by less team, and with better results than the plough 

 of older and more generally-known construction. 



By the use of this implement we increase nearly every efiect 

 of underdraining, and we greatly hasten the process of deep 

 culture, inasmuch as the roots which penetrate the loosened 

 subsoil, being left to decay on the removal of the crop, give it 

 its required organic constituents, while the action of the air 

 and water circulating among its particles, advances the changes 

 requisite to its more perfect fertility. 



Aside from this use of the subsoil plough, it has another, 

 which promises well. Its construction allows it to be drawn 

 through old pastures and mowing lands, at a depth of a foot 

 or more, causing such a loosening of the lower soil as allows 

 the tilling of the grasses to recommence, and especially if some 

 concentrated manure be employed as a top dressing, in this 

 manner such lands may be renovated without the expensive 

 and troublesome recourse to a rotation of crops, which it is 



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