128 SOILS 



for the much greater efficiency of the bold mould- 

 board. 



A plow not adjusted properly may require 

 50 per cent, more energy to move it. The 

 investigation of Sanborn, in 1888, showed that the 

 use of a coulter or jointer increases the draft and 

 the use of a beam wheel decreases the draft. He 

 also found that the deeper a plow works, the less 

 draft it requires in proportion to the size of the 

 furrow-slice. That is, it does not take twice as 

 much power to turn a furrow 8 inches deep as to 

 turn one 4 inches deep, but less than this about 

 10 per cent, for each additional inch in depth, 

 according to results at the Utica Plow Trial in 

 1867. Likewise the wider the furrow the less 

 power is required in proportion to the soil turned. 

 With a bold mouldboard a furrow may be turned 

 two or three times as wide as it is deep; if the 

 mouldboard is less overhanging it is necessary to 

 turn narrow furrows in order to leave the soil in 

 good shape. 



Heavy Teams Do Better Work. It is a mistake 

 to plow with a light team, and nothing but the 

 most shallow and least efficient plowing can be 

 done with a single horse or mule. A light draft 

 not only makes the plowing more shallow than 

 if a heavy team were attached to the same plow, 

 but the plow works in a jerky manner, and it is 

 harder for both team and man. Roberts says: 

 "If the little plow turning a furrow only nine 

 or ten inches in width and six inches deep could be 

 exchanged for a plow capable of handling a furrow 

 sixteen inches wide and ten inches deep; and the 

 two 900 pound horses replaced by three of 1,200 

 each, the necessity for subsoiling would be obviated 

 and the cost of plowing diminished rather than 



