228 



Physics of the Soil. * 



278. Easy and Quick Movement of Teeth. A very im- 

 portant feature of a riding or walking sulky cultivator is to 

 have the gangs of teeth so swung from the carriage that a 

 slight effort will produce a quick and certain movement. 

 This is indispensable in order to work close to the rows. 



FIG. 66. Cultivator with rigid teeth; best where soil is heavy and not 



stony. 



279. The Teeth of the Cultivator Adjustable. Another 

 important feature sulky cultivators should possess is the 

 possibility of tilting the gangs so as to allow them to work 

 more deeply in the soil toward the center of the row in the 

 later stages of cultivation because then the roots near the 

 rows have developed close to the surface, and deeper culti- 

 vation in the center, where the soil is more exposed to the 

 sun, is needed for effectiveness as a mulch. 



280. Covering Weeds in the Row. It sometimes happens 

 with the most careful management that weeds will get such 

 a start in the row that either hand hoeing must be resorted 

 to or else a tool must be used which will throw enougH 



