CULTIVATION IN DRY AREAS 147 



One great advantage of the two-section disc cul- 

 tivator arises from the fairly regular depth to which 

 the disc will cut regardless of the unevenness of the 

 surface. A double-action disc is now in common use 

 which will double disc the ground at one operation. The 

 first section breaks the soil and the second reworks and 

 firms it, and as the gangs are outthrow and inthrow the 

 land is left in a good condition. The size of the wheels 

 or discs is ordinarily from 12 to 20 inches, and the width 

 of the land stirred is from 6 to 10 feet. Usually discs 14 

 to 16 inches in diameter do more effective work than 

 those that are narrower, but they are heavier of draft. 



The disc may in all instances be used: (1) In the 

 early spring on fall-plowed land that has become more 

 or less impacted, to aid in making a good seed bed. (2) 

 On summer-fallowed land, in the absence of a more ef- 

 fective implement, to dislodge weeds which have become 

 so firmly rooted that the ordinary harrow cannot dislodge 

 them. (3) On summer-fallowed land to break the sub- 

 surface crust that in some instances forms beneath the 

 dust mulch made by the harrow. (4) On cultivated land, 

 as corn, when preparing it for the grain or alfalfa crop 

 that is to follow. To plow such land would result in the 

 loss of moisture and would bring up weed seeds from 

 below, which would tend to cover the land with weed 

 life. (5) On breaking or sod land, setting the discs so 

 straight as not to bring up sods. The object is to press 

 down the furrow slice and to aid in making a soil mulch. 



It may be used in many instances : (1) On stubble 

 land as soon as practicable after the grain has been re- 

 moved to destroy weeds that are then growing, to en- 

 courage germination in weed seeds and in volunteer 

 grain, to prevent the escape of subsoil moisture, to open 

 the soil for the easy penetration of rain, and to make 

 more easy the plowing of the land at a later period. 



