sept. 9. X9is Deep Tilling and Dynamiting in the Great Plains 509 
crop of 1913 follows the outline in its entirety as regards depth of tillage. 
In the particular of crop sequence the four com plots and the four wheat 
plots that should have followed wheat were on fallow land. Winter 
wheat was used in this experiment only the one year, durum wheat 
having been grown since the first crop. 
Ordinary plowing has been done uniformly to the depth of 7 inches 
with a moldboard plow of the sulky type. Deep tilling has been done 
to the depth of 14 inches each year. Plowing for wheat has been done 
in the fall; plowing for corn has been done in the spring of each year, 
except in preparation for the crop of 1913. 
The outline was departed from in preparing for the crop of 1916. The 
4 com plots that were to be sown to wheat were not plowed, but were 
double-disked in preparation for seeding. The 12 other plots—4 corn 
plots to be planted to com, 4 wheat-stubble plots to be planted to com, 
and 4 wheat-stubble plots to be planted to wheat—were all plowed 6 
inches deep in the spring of 1916. 
The results of this experiment for the six years 1911 to 1916, inclusive, 
are given in Table XVI. The yields given in this table are arranged 
under 16 heads: (1) Wheat following wheat on land deep-tilled each year, 
plot L; (2) wheat following wheat the first year after deep tillage on land 
deep-tilled every other year, plot J in the odd years and M in the even; 
(3) wheat following wheat the second year after deep tillage on land 
deep-tilled every other year, plot M in the odd years and J in the even; 
(4) wheat following wheat on land ordinary plowed each year, plot K; 
(5) wheat following com on land deep-tilled each year, plot D in the odd 
years and N in the even; (6) wheat following com the first year after 
deep tillage on land deep-tilled every other year, plot B in the odd years 
and O in the even; (7) wheat following corn the second year after deep 
tillage on land deep-tilled every other year, plot C in the odd years and 
P in the even; (8) wheat following com on land ordinary plowed each 
year, plot A in the odd years and Q in the even. (9-16) Eight similar 
combinations of crop sequence and tillage method occur with the corn 
crop. 
At the right of Table XVI are two averages. The first needs no 
explanation, being the average of each method for the entire period of 
years. Under the com crop the grain average is the average of the 
three years when grain was produced and the fodder average is the 
average of the total weights for the three years when little or no grain 
was produced. The second average is the average of the two crop 
sequences on similar conditions of depth of cultivation. 
The results given in Table XVI show a rather striking effect of crop 
sequence. Wheat following com and corn following com are both 
markedly better than the same crops following wheat. This positive 
result is the more striking when considered in connection with the lack 
of difference in the average yields resulting f r om the very marked dif- 
