sept. 9,1918 Deep Ttiling and Dynamiting in the Great Plains 
517 
In the results from the wheat crop no difference is exhibited between 
the yields from the plots dynamited each year and from those plots dyna¬ 
mited every other year either where wheat follows wheat or where wheat 
follows com. All of these apparently have an advantage of about 3 
bushels per acre over the plots not dynamited at all. 
The yields from the com crop exhibit a marked effect as a result of 
crop sequence, the average yield following corn being nearly ^ ton per 
acre greater than the average yield following wheat. Every plot follow¬ 
ing corn has outyielded every plot following wheat. No such marked 
effect or consistency of results is to be noted as a result of dynamiting. 
The yield of the plot dynamited each year has been practically the same 
as the yield the second year after dynamiting on the plot alternately 
dynamited and not dynamited. 'Both of these yields have been about 
600 pounds per acre greater than those from the plot not dynamited at 
all and from the first year after dynamiting on the plot alternately 
dynamited and not dynamited. This inconsistent combination of results 
indicates very strongly that the variations are accidental rather than 
due to the effects of dynamiting. 
Granting the proposition, which is by no means conclusively proved 
by the data at hand, that yields may be slightly increased by the use of 
dynamite, the possible increase is too small to hold out any hope of the 
operation being profitable even if the effect of the dynamite persisted 
for a considerable number of years. 
SUMMARY OF RESULTS OF DEEP TILLAGE BY THE USE OF DYNAMITE OR 
SPECIAL PLOWS 
In summation of the results from all stations it seems very questionable 
that deep tillage either by the use of special plows or dynamite has been 
effective in increasing yields. The most favorable evidence is with corn 
the second year after dynamiting at Akron; with wheat the second year 
after dynamiting at Ardmore; and with wheat after dynamiting at 
Judith Basin, The apparent increases in these cases are small and are 
offset by losses so that the averages of all trials with both crops show no 
increases over ordinary plowing. 
Deep tilling by these methods, as well as by subsoiling, has been of 
no value in overcoming drouth. 
The results offer no hope of profitably increasing the yield of either 
wheat or corn by means of deep tillage. 1 
RESULTS OF OTHER INVESTIGATIONS OF SUBSOILING AND DEEP 
TILLING 
Utah. —Experimental work has been conducted cooperatively at the 
Nephi, Utah, Substation since 1907 by the Office of Cereal Investigations 
of the Bureau of Plant Industry and the Utah Agricultural Experiment 
Station. 
1 These conclusions are supported and strengthened by the results of 1917, which was a year of low yields 
owing to drouth. 
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