8 BULLETIN 814, IT. S. DEPARTMENT OF AGRICULTURE. 
gang plow cover .86 acre and .91 acre per horse, respectively. Four 
horses on the sulky plow and six horses on the gang plow cover .72 
and .78 acre per horse, respectively. However, the gang plow is 
evidently a heavy load for four horses in the fall, excepting under 
favorable conditions. The 28-inch gang is a somewhat heavier load 
for six horses, the most popular sized team used in the fall, than is 
the 16-inch sulky for four horses, but is a lighter load than the 16- 
inch sulky for three horses. 
As far as man labor is concerned, the gang plow drawn by six 
horses is, of course, the most efficient unit both in the spring and 
fall, but when horse labor as well as man labor is considered, it is 
seen that the advantage of this largest unit is somewhat lessened. 
TRACTOR PLOWING. 
Table VI shows the daily performance for both spring and fall 
of 2 and 3 bottom 11-inch plows pulled by tractors, as given by the 
farmers using power outfits. 
Table VI. — Tractor ploioing. 
Width 
of furrow. 
Spring. . Fall. 
Number of 
reports. 
Acres Number of 
per day. reports. 
Acres 
per day. 
Inches 
28 
42 
19 
42 
7.00 21 
8.67 46 
6.3S 
8.06 
A comparison of the work done by tractor-drawn plows cutting 
28-inch furrows with that of plows of the same size drawn by horses, 
shows that in the spring the tractor does about 30 per cent more work 
per day than six horses, and in the fall about 35 per cent more, and 
that it does about 40 per cent more than four horses in the spring, 
and 55 per cent more than four horses in the fall. The tractors 
plowed to approximately the same depth, and worked approximately 
the same number of hours per day as did the horses. 
The acres covered per day per plow are from 15 to 20 per cent less 
for the 3-plow outfits than for the 2-plow machines. As compared 
with the horse-drawn sulky plow, the 3-bottom tractor plow does on 
the average from two and three-fourths to three times as much as a 
16-inch sulky drawn by three horses in the spring, or the same im- 
plement drawn by four horses in the fall. (See fig. 2.) 
The reports of over 600 tractor owners throughout the State of 
Illinois as summarized in Farmers' Bulletin 963, " Tractor Exper- 
ience in Illinois," showed an average of 6^ acres per day of 10 net 
working hours for 2-plow tractors and 8 j acres for 3-plow machines. 
(Compare with Table VI.) 
