202 POWER AND THE PLOW 



than old ground, so that tearing and pulverizing implements 

 may have a thinner layer to work upon. It is quite necessary 

 that a shallow layer be well cut up, as a mat of dry vegetation 

 between the subsoil and seedbed checks the capillary rise of 

 water. Occasionally the depth of fertile soil limits that of plow- 

 ing. Beavers says, in Farmers' Bulletin 398: "It has been 

 demonstrated by farm practice in the South that where the 

 soil is plowed deep more fertilizer can be used profitably than 

 on soil plowed shallow. " 



The cereal crops are naturally rather shallow feeders; hence 

 in humid climates plowing is at less depth for wheat, oats, etc., 

 than for corn and root crops. They require a firmer seedbed, 

 which is of further advantage in saving power at cutting time. 

 Corn requires a larger feeding area for its roots than the smaller 

 cereal plants; hence plowing in corn ground is usually from one 

 to three inches deeper. The leading agronomists of the Corn 

 Belt unanimously recommend plowing for corn at a depth of 

 from six to nine inches. Recent experiments with a deep 

 tilling machine have been followed by a remarkable increase 

 in the yield of corn on fields plowed to a depth of from ten to 

 fourteen inches. Root crops, such as potatoes and sugar beets, 

 require deep plowing, twelve inches for the latter being con- 

 sidered the possible minimum in the heavy adobe soil of Col- 

 orado and California. 



In the semi-arid regions deep plowing is prerequisite to highly 

 successful farming. However, Western farm horses are often 

 small, few in numbers, and not cared for in a way to obtain 

 their maximum efficiency; hence, shallow plowing is the rule 

 rather than the exception. The soils have become solidified 

 by the tramping of many generations of animals and by the 

 rains of centuries. Moisture penetrates only a short distance 

 except where the ground has been loosened by artificial agencies. 

 Professor Buffum, of Wyoming, states that some of these soils, 

 when in excellent tilth, will absorb over 40 per cent, of their 

 weight of water. As the. lack of moisture is the limiting 



