WORKING THE SOIL 



141 



ficient to make the same kind of a mark when the plow 

 is not turning a furrow. 



One advantage in riding plows in addition to the 

 relief of such a load is less packing of the furrow bot- 

 tom. On certain soils when the moisture is just suffi- 

 cient to make the subsoil sticky, a certain portion of the 

 furrow bottom is cemented by plow pressure so that it 



Figure 136. Three-Section, Spike-Tooth Harrow. The harrow is 

 made straight, but the hitch is placed over to one side to give each 

 tooth a separate line of travel. 



Figure 137. Harrow Sled Long Enough to Hold a Four-Section 

 Harrow. 



becomes impervious to the passage of moisture either 

 up or down. The track of a plow wheel is less in- 

 jurious. 



Plow wheels should stand at the proper angle to the 

 pressure with especial reference to the work performed. 

 Wheels should be adjusted with an eye single to the 

 conditions existing in the furrow. Some wheel plows 

 apparently are especially built to run light like a 

 wagon above ground regardless of the underground 

 work required of them. 



