70 BULLETIN 1039, U. S. DEPARTMENT OF AGEICLT^TURE. 



The differences in yields obtained from the three tillage treatments 

 are rather small. However, the results were the same for all four 

 crops. In all cases the plats receiving no tillage treatment in the. 

 fall gave the highest yields, the plowed plats gave the nest highest, 

 and the subsoiled plats the lowest yields. Under the conditions of the 

 experiment, plowing or subsoiling of corn ground in preparation for 

 spring grain proved to be harmful rather than a benefit. The results 

 are not entirely conclusive, because of having been obtained for only 

 one year. 



SUMMARY. 



The experiments here reported were conducted on dry land during 

 the 12 years from 1908 to 1919, inclusive, and on irrigated land dur- 

 ing the 8 years from 1912 to 1919, inclusive. 



The Belle Fourche Experiment Farm is located in the western part 

 of South Dakota, about 30 miles northeast of the Black Hills. The 

 results obtained are applicable to western South Dakota and adjoin- 

 ing sections in northeastern Wyoming, southeastern Montana, and 

 southwestern North Dakota. 



The soil on which these experiments were conducted is a heavy, 

 impervious clay, or gumbo, known as Pierre clay. 



The average annual precipitation for the 12 years was 14.31 inches 

 and the seasonal precipitation, March to July, inclusive, averaged 

 8.57 inches. The annual precipitation ranged from 6.64 inches in 

 1911 to 21.02 inches in 1915. The seasonal precipitation is an impor- 

 tant factor influencing the yields of grain. The average jT-elds of the 

 best varieties of wheat, oats, and barley on dry land have been fairly 

 satisfactorj^, but partial or complete failures in some years have made 

 grain growing uncertain. Other small grain crops are not as suc- 

 cessful as wheat, oats, and barley. 



Durum wheats have given higher yields than common spring 

 wheat. Kubanka is the highest yielding variety. Marquis has given 

 the highest yields of any of the common spring-wheat varieties. 

 Kubanka wheat should be sown at the rate of about 4 pecks per acre 

 on an ordinarj'^ seed bed. The wheat should be sown as early as 

 weather and soil conditions permit. 



The hard red winter wheats, Turkey and Kharkof, have produced 

 the highest yields of the winter varieties. These two varieties are of 

 equal value and are apparently identical. 



Seeding at the rate of 4 pecks per acre has given the highest net 

 yields on fallowed land. The best date of seeding for winter wheat 

 is about September 16. Early-sown wheat does not sur^nve the 

 winter better than late-sown wheat. 



