Journal of Agricultural Research 
Vol. XIV, No. II 
SIS 
Cardon (1) summarizes the results of five years' work with deep tillage 
for winter wheat as follows: 
The results of five years show that there was no advantage in deep plowing or sub- 
soiling over shallow plowing so far as moisture conservation is concerned. There 
was no material difference in the yields obtained from plats plowed at different 
depths, varying from 5 to 18 inches. The highest average yield was obtained from 
plats plowed 10 inches deep, and the lowest average yield was from the plats sub¬ 
soiled 18 inches deep, while the 5-inch plowing yielded higher than the 15-inch 
subsoiling. 
Illinois. —Mosier and Gustafson (4) report the results of investiga¬ 
tions in Illinois as follows : 
Investigations to determine the value of subsoiling in preparation for com on gray 
silt loam on tight clay, the common prairie soil of the lower Illinois glaciation, have 
been carried on for eight years at the Odin Field, in southern Illinois. * * * With 
every soil treatment there was an almost uniform decrease in yield for subsoiling. 
The general average for eight years shows a decrease of 2.7 bushels per,acre. The 
alleged benefit of subsoiling is the increasing of the water capacity of soils and of 
their ability to retain water during dry seasons. Yet in 1913 and 1914, both of which 
were very dry seasons, this method, as a general average, gave only the very slight 
increase of .5 and .7 bushels respectively. The subsoil was loosened by the plow, 
but ran together as soon as it was wet and became approximately as it was before. 
The experiments as a whole show that subsoiling on this type of soil not only does 
not pay, but is a losing operation, for in order to pay for the extra work involved in 
subsoiling, at least a three-bushel increase would be necessary. 
Under the head of “Deep tilling" in the same bulletin the authors 
present no data of yield,but make the following statement: 
Farmers are frequently urged to purchase a machine for plowing to a depth of 12 to 
15 inches. There is little doubt that under certain conditions of soil and climate 
such plowing would be beneficial; but the results obtained by the Experiment 
Station in this state with the deep-tilling machine on the common prairie soil of the 
corn belt do not warrant recommending its purchase. 
Pennsylvania.— Noll (5) summarizes the result of three years' trial 
of the Spalding deep-tillage machine on the farm of the Pennsylvania 
State College as follows: 
The soil in which this experiment was conducted is of the Hagerstown series. It 
varies in texture from clay loam to gravelly silt loam, but is chiefly clay loam. The 
surface soil is so deep that in most of the area little of the clayey subsoil was turned up. 
The soil is well drained. 
Eight plats 35.5 ft. wide, varying in length from 902.5 ft. to 1,000 ft. were plowed at 
first. These were later made 957.2 ft, long and comprised .78 of an acre each. 
Timothy sod was plowed for com in the fall of 1909 and the spring of 1910, two 
plats being plowed with each implement in the fall and two in the spring. 
In the fall of 1910 and the spring of 1911 the com stubble land was plowed in the 
same way, and in the spring four plats were seeded to oats and four to beardless barley 
and alfalfa. 
In the fall of 1911 the four plats which had received oats were plowed and seeded 
to wheat, two plats being plowed with each implement. 
The crops for which the plowing was done were com, oats, barley, wheat, and 
alfalfa, each one year. 
Under the conditions named above the two kinds of plowing gave practically the 
same results for all the crops grown. 
