34 BULLETIN 595, U. S. DEPARTMENT OF AGRICULTURE. 
hart, and Tucumcari it is greater. The greatest differences between 
the net returns from the two crops are $9.28 at Hays, $5.45 at North 
Platte, and $4.71 at Akron, all being in favor of winter wheat. At 
only 3 of the 13 stations (Garden City, Dalhart, and Tucumcari) 
are the returns from summer tillage greater for spring wheat than for 
winter wheat. At all the other stations winter wheat shows larger 
net returns after summer tillage than spring wheat. 
These results indicate that winter wheat rather than spring wheat 
should be grown under conditions similar to those existing at Huntley, 
North Platte, Akron, and Hays, and probably at Scottsbluff, Belle 
Fourche, and Judith Basin. At Archer and Ardmore, where the 
results are available for only three years, the differences are so small 
that another year’s work might alter the averages considerably. At 
Garden City, Dalhart, and Tucumcari neither of the crops has re- 
turned a profit by any method. At Amarillo, under the methods 
which have yielded profits, those from winter wheat have been greater 
than those from spring wheat. 
CONCLUSIONS. 
These conclusions apply only to the yields of winter wheat as 
affected by the cropping and cultivation of the one year immediately 
preceding growth. ; 
(1) Some seasons are so unfavorable as to result in failure of the 
winter-wheat crop without regard to the cultural methods under 
investigation. Extremely unfavorable climatic conditions can not 
be overcome by cultural methods. 
(2) It is only in those seasons when the rainfall deficit is so small 
that it can be overcome by moisture stored in the soil that the cul- 
tural methods under investigation have shown important effects 
upon yields. 
(3) When the differences in the values of the yields are less than 
the differences in cost of production, then cost becomes the deter- 
mining factor. 
(4) Some soils, even in regions of profitable winter-wheat produc- 
tion, show little response to cultural methods. 
(5) Reducing the cost of production has in most cases in these 
investigations proved a more important factor in determining profits 
than increasing the yields by cultural methods. 
(6) The average difference in yields between early (deep) and late 
(shallow) fall plowing is 1 bushel per acre. At most stations the 
difference is small, while at others the advantage of one over the 
other depends on the season. At Scottsbluff, North Platte, Hays, 
and Amarillo the differences are rather consistently in favor of early 
plowing, and this method is more profitable at these stations. At the 
other stations late plowing has netted larger returns. 
