30 BULLETIN 222, U. S. DEPARTMENT OF AGRICULTURE. 
has been exceeded by both, but the differences among the three 
are only fractions of a bushel. At Amarillo disked corn land 
has been between fall-plowed and spring-plowed stubble in yield 
Its low cost of production has made it the most profitable method 
under trial at all stations except Hettinger. It has been productive 
of a profit at all stations except Garden City, Dalhart, and Amarillo. 
This study, dealing with but one crop, does not consider the relative 
profitableness of other crops in the farming system. 
It should be borne in mind that at all stations disking corn ground 
as a preparation for all small grain crops has been done upon corn 
land kept free from weeds. If weeds were allowed to develop in the 
corn, similar results should not be expected. To the extent that 
the weeds developed or were unhindered in their growth, just so far 
would the corn ground approach a grain stubble in the condition of 
the seed bed. If the weeds matured seed, further damage by their 
growth might be done to the succeeding crop. 
Preparing the ground with a lister instead of a plow has been 
practiced at eight stations. At only one station, Judith Basin, were 
the yields very materially different from those on fall-plowed land. 
But, as has been pointed out, the yields on fall-plowed land at that 
station were lowered somewhat by damage done by gophers. At 
the other stations, though it did not in all cases give higher yields 
than plowing, it showed, owing to a lower cost of preparation, slightly 
more profit where profits are shown and less loss where losses are 
shown than plowing. 
The difference between spring and fall plowing is largely one of 
season. In the average of the 13 stations at which both were under 
trial there is practically no difference. At only three stations is 
there a difference of over 2 bushels per acre. At the four more 
southern stations the advantage has been with fall plowing. This 
is the only consistent territorial difference to be noted in the com- 
parison of these two methods, but production at these four stations 
and at Belle Fourche has resulted in a loss by both methods. Spring 
plowing shows a profit at all other stations, and fall plowing shows 
a profit at all others except Scottsbluff. 
Subsoiling in preparation for the barley crop has been practiced at 
seven stations. At only two of these has the consequent" yield de- 
parted far from that on fall-plowed land. At the Judith Basin 
station there has been a marked gain and at Akron a marked de- 
crease. In the average of the seven stations the yield from this 
method has been only 0.4 of a bushel more than from fall plowing. 
The cost of the method has been such that it has paid a profit at only 
the Judith Basin station. 
The highest average yields at eleven of the fourteen stations have 
been by summer tillage. At the Judith Basin station subsoiled land 
