CORN IN THE GREAT PLAINS AREA. 



are water supply, physical condition of the seed bed, and a certain 

 recognized, although not fully understood, effect of the crop immedi- 

 ately preceding. Uniformity in these factors is largely restored by the 

 cultivation or crop- 

 ping of a single season. 

 After a careful study of 

 the data, it seemed ad- 

 visable to present in 

 this bulletin the yields 

 of corn as determined 

 by the cropping and 

 treatment of the land 

 in only the one year 

 immediately preced- 

 ing the growth of the 

 crop. 



In the study that 

 is here made only the 

 more important and 

 obvious results will be 

 discussed. The tables 

 themselves when crit- 

 ically studied show 

 much more than is 

 here mentioned. No 

 attempt is made to 

 study rotations as a 

 whole. There are 

 cumulative effects of 

 rotations and farm- 

 ing systems that are 

 not negligible, but 

 which are not dis- 

 cussed here. Other 

 studies have shown 

 that these effects are 

 of far less immediate importance than the effect of the preceding 

 crop, the preparation of the seed bed, and the seasonal conditions. 



AREA COVERED BY THESE STUDIES. 



The area (fig. 1) included in these investigations covers a part of 

 ten States: Montana, North Dakota, South Dakota, Wyoming, 

 Nebraska, Colorado, Kansas, Oklahoma, Texas, and New Mexico* 

 It extends from the ninety-eighth meridian of longitude to the foot- 

 hills of the Rocky Mountains and from the Canadian border to the 

 thirty-second parallel of latitude. 



Fig. 1.— Sketch map of the Great Plains area, which includes parts of 

 ten States and consists of about 400,000 square miles of territory. 

 Its western boundary is indicated by the 5,000-foot contour. The 

 location of each field station within the area is shown by a dot within 

 a circle (©). 



