32 BULLETIN 222, U. S. DEPARTMENT OF AGRICULTURE. 
stations. The only profit shown at any of these stations is 35 cents 
an acre on disked corn ground at Belle Fourche. 
(3) The highest average yields at eleven of the fourteen stations 
have been by summer tillage. On the average, it increased the 
yields nearly one-half over those produced on land cropped in the 
preceding year. On account of its cost it has not been the most 
profitable method of production. 
(4) At ten of the fourteen stations under study disked corn 
ground produced higher yields than from either the fall plowing or 
the spring plowing of barley stubble. It has been the most profitable 
method under trial at all the stations except Hettinger. 
(5) The relative advantage of either fall or spring plowing is 
largely dependent upon the season. In the general average of the 
thirteen stations at which each method has been tried there is prac- 
tically no difference. At only three stations has there been an 
average difference of over 2 bushels per acre between the two meth- 
ods. At the four more southern stations fall plowing has been bet- 
ter than spring plowing. 
(6) At the seven stations where subsoiling for barley has been 
tried it has produced an average of only 0.4 of a bushel more than 
fall plowing. At only two stations has there been a marked difference 
in the results of the two methods. At one of these, subsoiling has 
been responsible for an increase and at the other for a decrease in 
yield. 
(7) At eight stations listing instead of plowing has been tried. 
While the resulting yields have not been materially different from 
those on fall-plowed land, the lower cost of listing has made it the 
more profitable method. 
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