472 NORFOLK SOCIETY. 



not common, but are found in the form of alluvial deposits, 

 and sometimes in districts of "secondary" formation. When 

 the surface, in such cases, becomes exhausted by cropping, the 

 bringing up of the subsoil renews the fertility. 



The character of the subsoil can readily be ascertained by 

 digging up a portion of it, and after exposing it to the frost 

 and air for a season, planting in it various crops. Chemical 

 analysis would show its particular qualities, and in connection 

 with a comparison with other soils whose character had been 

 ascertained by trial of crops, w^ould afford a useful guide. 



The "Michigan Sod and Subsoil" plough is well adapted 

 to trench or deep ploughing. It has two ploughs (or the 

 bodies of two) set in one beam and working in the same line. 

 The forward plough cuts and turns over two or three inches of 

 the surface, and the hinder one follows in the same furrow, 

 bringing up the lower earth and turning it completely over 

 that turned by the forward implement. It can be made to 

 work to the depth of a foot or more. It is obvious that in this 

 operation it effects twice as much division of the soil as the 

 ordinary plough, and where the soil is of a heavy and tenacious 

 character, this is of great importance. From this peculiarity, 

 a plough of this kind may likewise be used to great advantage, 

 and is probably superior to any other, for all soils which are 

 required to be ploughed to a greater depth than seven inches. 



4. Subsoil Ploughing. This differs from trench ploughing 

 by simply loosening and breaking the substratum, without 

 reversing the former relations of the soil and subsoil. As yet, 

 it has hardly been tried in this country sufficiently to enable 

 us to specify its particular advantages from actual results. Its 

 effects in England have been very beneficial in connection with 

 drainage, on stifi" soils, and so far as ascertained, its effects are 

 the same here. The breaking up of the subsoil favors the de- 

 scent of the water to the drains. When the water remains 

 long in the soil, in undue quantity, it runs the particles to- 

 gether and packs them in solid mass. Hence it has been 

 found necessary to carry away the water before it can accu- 

 mulate in sufficient quantities to produce this result. By 

 means of drains, and a thorough opening of the soil and sub- 

 soil, this is accomplished. 



