10 



BULLETIN 814, U. S. DEPARTMENT OF AGRICULTURE. 



An average day's work in going once OA^er well-packed land (with- 

 out any lap) for 7, 8, and 9 foot disks, drawn by 4 horses, and 10- 

 foot disks drawn by 6 horses, is given in Table VII. The average 

 performance of the same units in going once over freshly plowed 

 land (without any lap) is given in Table VIII. 



Table YIII. — Disk harroio on freshly-plowed land. 



Width. 



Number of 

 horses. 



Number of 

 reports. 



Acres per day. 



Average. 



Acreage most 

 often reported. 



Feet. 



7 

 8 

 9 



10 



4 



4 

 4 



6 



60 



308 



15 



23 



14.3 



15.5 

 16.9 



22.7 



15 (25 reports). 

 loUll reports). 

 Scattering. 

 (20 (7 reports). 

 \25 (7 reports). 



Many farmers report that there is practically no difference be- 

 tween the rate of doing work on well-packed land and freshly- 

 jDlowed land, as the disks must ordinarily be set at a somewhat 

 greater angle in disking corn stubble or fall plowing, thus making 

 the draft of the implement greater and overcoming the advantage 

 of firmer footing for the horses. On an average, however, a day's 

 work on well-packed land is .from 1 to 2 acres greater than on 

 freshly plowed land. 



The 9-foot disk, drawn by 4 horses seems to be the most efficient 

 unit so far as horse labor is concerned, this unit covering about 4.7 

 acres per horse per day on well-packed land, and 4.2 acres on freshly- 

 plowed land. However, the fact that so many men are using 8- foot 

 disks indicates that the 9-foot size is perhaps a slight overload for 

 4 horses. 



A 10-foot disk makes the same load per horse for 5 horses as the 

 8-foot implement does for 4 horses, but most of these farmers who 

 use 10-foot disks hitch 6 horses to them. While such an outfit per- 

 mits one man to cover more ground j)er. day than does any of the 

 other units shown in the tables, the efficiency of the horse labor 

 is less than when 4 horses are used with the 8-foot disk. 



THE SPIKE-TOOTH HARROW. 



Spike-tooth harrows ranging from 12 to over 25 feet in width 

 were reported, and 95 per cent of the farmers stated that they 

 hitch 4 horses to this implement. Fewer than 20 farmers using 

 3-section harrows, each section being from 4 to 5 feet wide, reported 

 the use of 3 horses, and about the same number reported 5 and 6 

 horses for harrows 16 feet or more in width. (See Table IX.) 

 Eighty per cent of these men use 4-section harrows, and about 50 



