WHEAT, OATS, AND BAELEY IN SOUTH DAKOTA. 3 



maturing varieties as well as early or late seeding. The whole ques- 

 tion depends upon the time of occurrence of the hot wind or the high 

 evaporation. Thus, some seasons are favorable to early-maturing and 

 some to late-maturing kinds. A 10-year average shows little differ- 

 ence between the yields of good early and good late varieties. The 

 hot winds have sometimes occurred during the last week in June, in- 

 juring early varieties, while in other seasons they have occurred dur- 

 ing the last half of July, thus injuring the late varieties. Only once 

 during the 10-year period (in 1911) have they been so serious as to 

 totally destroy the cereal crops at the western substations. 



£o'g== 



LeSSTHAH/5/s/. /STOSOM. 20 TO 25 M. MOfi£ THAN 25M. 



Fig. 1.— Map of South Dakota, showing the average annual precipitation in inches and 

 the location of the agricultural experiment station and substations. 



The monthly, seasonal, and annual rainfall by years at the stations 

 at Brookings, Highmore, Eureka, and Cottonwood, S. Dak., are 

 shown in Table I, with averages for the periods for which records are 

 reported and a summary of these averages. 



Table I shows that the average seasonal rainfall at Brookings for 

 the five months from April 1 to August 31 is 15.63 inches, or 68 per 

 cent of the annual precipitation. June has been the month of great- 

 est rainfall, with May ranking next in order. There have been two 

 seasons when drought conditions occurred, 1904 and 1910; 1908 was 

 the year of greatest rainfall. In 1903 the cereal crops at Brookings 

 were destroyed by hail, a fact not shown in Table I. In brief, there 

 have been seven good and three poor crop years in the 10-year period 

 from 1903 to 1912. 



