WINTER-WHEAT PRODUCTION AT FORT HAYS STATION. « 23 
tible of satisfactory explanation, but the reasons for the second con- 
dition are not so obvious. The stubble affords winter and spring 
protection to the wheat. It also catches snow during the winter and 
checks evaporation from the surface during the winter and spring. 
Then, as has been pointed out in considering the results on fallow, 
there are years when the heaviest early-season growth does not fulfil 
its prospects of making the heaviest crop of grain. The seven years 
covered by this phase of the experiments have embraced an unusual 
proportion of good wheat years and perhaps an unusual number of 
years favoring the poorer methods. It is therefore possible that a 
continuation of these experiments may not show as favorable results 
for the unplowed plats as has the period under discussion. 
The data from the Fort Hays branch station and other field stations 
on the Great Plains show that in years sufficiently favorable to pro- 
duce a crop, winter wheat is well able to compete with annual weeds 
because of the start it has over them in the spring. Spring-sown 
grains do not possess this ability to anything like the same degree, 
for the reason that the weeds start with such crops or even in advance 
of them. On this account plowing is of much greater import to 
spring-sown than it is to fall-sown grains. 
The evidence indicates that on land free from perennial weeds and 
grasses annual plowing for winter wheat may not be as necessary an 
operation as has generally been believed. 
CORN AND KAFIR AS PREPARATIONS FOR WHEAT. 
In 1915 four 2-year rotations were started to compare corn and kafir 
as preparations for winter wheat and to determine the effect on the 
yield of wheat of limiting the stand of corn and kafir on the ground 
by planting only every other row. 
Rotation No. 149 is corn ordinarily spaced, followed by wheat on 
disked corn ground. Rotation No. 150is the same, but with the rows 
of corn twice asfar apart. Rotation No. 349 is kafir ordinarily spaced, 
followed by wheat on disked kafir ground; and rotation No. 350 is 
the same with the kafir rows twice as far apart. Started in 1915 
these rotations were in full swing in 1916. Table 10 gives the yield 
of wheat in these rotations for the 5-year period from 1916 to 1920, 
inclusive. These yields show a decided advantage of corn over kafir 
as a preparation for wheat. Limiting the stand of kafir has had a 
decided effect in increasing the yield of wheat, but with corn there has 
been little or no such effect. 
The yield of wheat following even a one-half stand of kafir has not 
been equal to that following a full stand of corn: Wheat on fallow 
in rotation No. 560 adjoining these plats has averaged 20.2 bushels 
for the same years. Thisis a gain of 1.5 bushels over ordinary-spaced 
corn and only 0.3 of a bushel over double-spaced corn, but a gain of 
