WIN^TEE-WHEAT PRODUCTION AT FOET 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 \\dnter 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 abihty 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 Xo. 149 is corn ordinarily spaced, followed by wheat on 

 disked corn ground. Rotation No. 150 is the same, but with the rows 

 of corn twice as far apart. Rotation No. 349 is kafir ordinarily spaced, 

 foUowed by wheat on disked kafu* 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 httle 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. This is 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 



