144 FARM MECHANICS 



Those old-fashioned Scotch plows turn a furrow 

 about two-thirds of the way over, laying the sod surface 

 at an angle of about 45 to the bottom of the furrow. 

 The sharp comb cut by the coulter and share stands up- 

 right so that a sod field when plowed is marked in sharp 

 ridges six or seven inches apart, according to the width 

 of the furrow. Edges of sod show in the bottoms of 

 the corrugations between these little furrow ridges. 



When the rains come the water is held in these 

 grooves and it finds its way down the whole depth of 

 the furrow slice carrying air with it and moistening ev- 

 ery particle of trash clear to the bottom of the furrow. 

 Such conditions are ideal for the work of the different 

 forms of bacteria to break down plant fibre contained 

 in the roots and trash and work it into humus, which 

 is in turn manipulated by other forms of soil bacteria 

 to produce soil water which is the only food of grow- 

 ing plants. 



Jointer Plows. American plow makers also have 

 recognized the necessity of mixing humus with soil in 

 the act of plowing. To facilitate the process and at the 

 same time turn a wide furrow, the jointer does fairly 

 good work when soil conditions are suitable. The 

 jointer is a little plow which takes the place of the 

 coulter and is attached to the plow-beam in the same 

 manner. The jointer turns a little furrow one inch 

 or two inches deep and the large plow following after 

 turns a twelve-inch or fourteen-inch furrow slice flat 

 over, throwing the little jointer furrow in the middle 

 of the furrow bottom in such a way that the big furrow 

 breaks over the smaller furrow. 



If the work is well done, cracks as wide as a man's 

 hand and from three to five inches deep are left all over 

 the field. These cracks lead air and moisture to rot the 



