16 BULLETIN 917, U. S. DEPARTMENT OF AGRICULTURE. 



the land is more often plowed the spring-tooth harrow is less fre- 

 quently used. A spring-tooth harrow does not do its best work on 

 land that is cloddy or rough, but it is an excellent tool with which 

 to loosen fall-plowed or early spring-plowed lands that have become 

 packed by heavy rains. It also works well in loose mellow fields 

 where some weeds have sprouted. On land which has been planted 

 to summer-tilled crops the spring-tooth harrow displaces the plow 

 in preparing the land for grain. 



The spring-tooth harrow of the Greeley region is usually in two 

 sections, each 6 feet in width, and is commonly operated by a crew 

 of one man and four horses. Such a crew will harrow approximately 

 8 acres in a 10-hour day. The average number of times this opera- 

 tion was performed in the Greeley region was 1.5 for beets, 1.3 for 

 grain, and 1.6 for beans. 



The spring-tooth harrow levels the land better than the disk, but 

 does not pack the sod so much. It leaves an excellent surface 

 mulch on the field. 



ROLLING. 



Smooth rollers are uncommon in the irrigated sections of Colorado, 

 but some men make use of the corrugated roller in preparing the 

 seed bed. Rollers are used for firming the soil after plowing and 

 for connecting the loose surface soil with the moist subsoil. They 

 may also be used for breaking or crushing clods. In the Greeley 

 region rollers are used to firm and smooth the seed bed for shallow- 

 planted seeds. With a firm upper layer of soil the drill plants at a 

 more even depth, and the moisture rises more evenly to the surface. 

 In this section 17 per cent of the farmers used the roller in preparing 

 the beet-seed bed, none used it for grains, and very little use was 

 made of it on bean or potato land. 



Fort Morgan operators used the roller to some extent on beet 

 land, but less use was made of it than in the Greeley district. No use 

 was made of it in grain seed-bed preparation. In the Rocky Ford 

 district some use was made of the roller on grain crops by 25 per 

 cent of the growers. One man rolled bean land, 14 of 110 rolled 

 beet land, and 13 of 29 cucumber and cantaloupe growers rolled 

 the seed bed. 



The common type of roller was 8 to 9 feet in length and was usually 

 operated by one man and two horses, although sometimes as many 

 as four horses were used. There is considerable variation in the 

 number of acres covered, 12 to 15 being an average day's work. 

 Usually the land is rolled but once. 



SPIKE-TOOTH HARROW. 



The spike-tooth harrow is used in the preparation of land for all 

 crops. All the Rocky Ford operators except one beet grower and 

 one wheat grower reported the use of this implement in seed-bed 



