SPRINCJ WHEAT IN THE GREAT PLAINS AREA. 13 
The most significant fact shown by Table V is the lack of material 
differences in yield resulting either from different methods of handling 
the soil in preparation for spring wheat or from the effect of the crop 
immediately preceding. This indicates that the place given to spring 
wheat in a rotation is comparatively unimportant. This is rather to 
be expected when the factors that determine production are under- 
stood in the light of recent information. There is not space here to 
discuss the subject, but suffice it to say: (1) On this rich, virgin, 
limestone soil, production is not immediately dependent upon in- 
creased f ertility or greatly influenced by additions to or removal of its 
elements; (2) the shallowness of the soil where it is underlain by non- 
functioning gravel, together with the usually heavy spring rains, 
makes it impossible to realize the benefits that might be expected to 
accrue from methods of cultivation calculated to add to the total 
moisture supply by storage of moisture in the soil. 
The problems appear to be those of good seed, good stand, freedom 
from weeds, and getting work done in proper season rather than those 
of certain methods of tillage. How soon results may become apparent 
from rotations that either add to or take from the fertility of the soil, 
it is impossible to predict. 
The variations in yields have been so small up to the present time 
that it is possible all may be within the limits of experimental error 
or due to variations existing in the soil. It would therefore be 
unprofitable to discuss in detail the small variations that appear. 
The results are, however, of great importance in the evidence they 
offer that no one of the methods tried is essential to success in the 
growth of spring wheat and in the consequent freedom allowed in 
arranging a cropping system which need not necessarily include any 
unduly expensive or laborious method as a requisite of production. 
Since there are no essential differences in yields from different 
methods at this station, it follows that the relative profit or loss has 
been largely determined by the cost of production. The spring wheat 
crop has been raised at a profit by all methods except that of green 
manuring. The largest profit has been obtained from disked corn 
ground. The value of it as a farm practice would depend upon the 
profitable growth or utilization of the corn crop in a farming system. 
The next highest profits have been obtained from listing instead of 
plowing. This again is due to the low cost of preparation. While 
the yield from summer tillage has been about the same as from other 
methods, the increased cost of this method has been sufficient to 
reduce the profit from $11 per acre on disked corn ground to $3.06 
per acre on summer-tilled land. 
The heavy cost of green manuring has caused it to be done at the 
nominal loss of 33 cents per acre, when its whole cost is charged to 
the first crop that follows it. From the standpoint of actual yields 
