The First Type of Subsoil Plow 



invented had a narrow share and a long moldboard, which would bring 

 subsoil to the surface. Theorists at that time believed that subsoil, 

 being new, was rich in plant food elements, and that it would make 

 their land productive. The absence, however, of humus in the suteoil 

 resulted in disappointments. If the subsoil was clay or sand, there 

 would be no production until organic matter was thoroughly mixed with 

 the soil and reduced to humus. 



The Next Type of Subsoil Plow 



devised was one with a duck-bill-shaped point, intended to break up the 

 soil below the bottom of the furrow. This implement was condemned, 



Proper Method of Subsoiling Is to Cut a Thin, Deep Gash in Bottoms of Alternating 

 Fiirrows .. In Dry Sections It Should Be Used in Every Furrow 



especially where the subsoil was hard and composed largely of clay, for 

 the reason that the breaking up process caused large air spaces which 

 practically stopped capillary water from rising to the seed-bed. 



The Modern Type of Subsoil Plow 



possesses none of the objectionable features of the other two mentioned, 

 but it does solve the difficulties which were first mentioned, namely, 

 dense, sticky subsoils and hard-pans. 



This plow is built on the principle of a colter. It cuts a gash from 

 three-eighths to one-half inch in width and to any required depth, but 



