6 BULLETIN 39, U. S. DEPAETMENT OF AGRICULTURE. 



clay containing rounded granitic stones commonly known as " hard- 

 heads." These glacial soils are well suited to cereal production. The 

 soils west of the Missouri River are alluvial or residual in their 

 origin, that is, they are either the result of deposits of sediment or 

 were formed in place by the disintegration of the underlying rocks. 

 For this reason these soils are extremely variable. Several types 

 of soil may be found on the same farm. The general soil types 

 include a sandy loam in the southern, a sticky clay in the central, 

 and a silt loam in the northern part of this section. 



The soil of the Brookings field is a medium sandy loam, that of 

 the Highmore field a medium clay loam, that of the Eureka field a 

 sandy loam, and that of the Cottonwood field a sticky clay, known 

 locally as gumbo. 



Thus, the four fields represent, in a general way, the common soil 

 types of the State. However, there are many local variations in the 

 character of the soil which may influence the results when the crops 

 here discussed are grown on other farms. 



HISTORY OF THE COOPERATIVE EXPERIMENTS. 



The cooperative study of the grain crops in South Dakota was 

 begun in 1903 by the South Dakota Agricultural Experiment Station 

 and the Office of Cereal Investigations of the United States Depart- 

 ment of Agriculture. The first purpose of the work was to determine 

 what varieties were best adapted to South Dakota conditions. Sev- 

 eral hundred introductions were made from various parts of the 

 world and were placed on trial. Many were found to be entirely 

 unfit the first season, while others were grown for several years before 

 it could be definitely determined whether they were suitable. The 

 varieties discussed in this bulletin are the best of the many which 

 were tested. After having learned something of the relative value 

 of the different varieties, work was begun in 1910 toward the improve- 

 ment of the best ones. 



Portions of the work have been reported from time to time in 

 various bulletins of the South Dakota Agricultural Experiment 

 Station * and of the United States Department of Agriculture. 2 The 



1 Shepard, J. IT. Macaroni wheat ; its milling and chemical characteristics. South 

 Dakota Agricultural Experiment Station, Bulletin 82, 45 p., 6 pi., 1903. 



Chilcott, E. C, and Cole, J. S. Cooperative cereal investigations at Highmore. Sum- 

 mary of results for 1903. South Dakota Agricultural Experiment Station, Bulletin 84. 

 p. 9-14, 1904. 



Shepard, J. H. Macaroni wheat ; its milling and chemical characteristics and its 

 adaptation for making bread and macaroni. South Dakota Agricultural Experiment 

 Station, Bulletin 92, 39 p., 4 pi., 1905. 



<'oie, I. S., and Balz, Sylvester. Cereal investigations at Highmore. South Dakota 

 Agricultural Experiment Station, Bulletin 96, p. 45-60, fig. 4, 1906. 



Shepard, J. II. Macaroni or durum wheats. (A continuation of Bulletin 92.) South 

 Dakota Agricultural Experiment Station, Bulletin 99, p. 105-115, 1906. 



