28 BULLETIN 214, U. S. DEPARTMENT OF AGRICULTURE. 



wheat crops raised on corn ground, oat stubble, and wheat stubble 

 with those on spring-plowed or fall-plowed ground after any crop, or 

 on disked-corn ground as a preparation for wheat, shows no wide 

 differences in yields. A small average difference in favor of fall 

 over spring plowing is shown. Fall plowing of corn ground in prepa- 

 ration for wheat appears from the returns of two plats so treated to 

 have been considerably better than either disking or spring plow- 

 ing it. 



The one plat of wheat on spring plowing following wheat has given 

 an average yield of 12.2 bushels per acre. This plat is plowed shal- 

 low while the others are plowed deep, as heretofore explained. The 

 departure of this method from the others in yield appears to have 

 been dependent upon the seasons and is not consistent from year to 

 year. 



Summer tillage for wheat at this station seems to stand by itself 

 as a means of increasing the yield. The largest increases in bushels 

 from this method have been obtained in the best years. After the 

 first year of a period of dry years, which began in 1910, summer tillage 

 has not been able, except in 1914, to increase yields or even, in some 

 cases, to maintain them at the standard set by less expensive methods. 

 While it is not shown in the present study, a much greater response 

 to summer tillage is obtained with winter wheat. 1 Consequently, 

 in spite of the fact that this method has been productive on the 

 average of more bushels per acre of spring wheat than any other, it 

 will not find favor in farm management as a general practice for the 

 growth of spring wheat. 



When the cost of production is considered, it is seen that the yield 

 obtained by summer tillage has been enough to pay for the cost of 

 the method. For the eight years under study it shows an average 

 profit of 26 cents per acre. Fall plowing and spring plowing show 

 profits of only $1.56 and $1.33 per acre for the same period. The low 

 cost of preparation is responsible for making disked corn ground show 

 an average annual profit of $2.53. 



While the spring wheat crop has been raised without much net 

 profit, it seems that it might afford a market for the labor of men 

 and teams and pay for the use of the land. 



AKRON FIELD STATION. 



The soil at the field station at Akron, Colo., is of a clay-loam type, 

 locally known as "tight land." It is characterized in the native 

 vegetation by a growth of short grass. As it carries in each unit sec- 

 tion a considerable proportion of water available to the crop and as 

 it offers no physical resistance to the development of roots, it is pos- 

 sible to store in it a large quantity of water available to a crop. It 



1 See Nebraska Experiment Station Bulletin 135. 



