8 BULLETIN 2*70, tJ. S. DEPARTMENT OF AGRICULTURE. 



Table IV.- — Summary of mean, maximum, and minimum temperatures at the Williston 

 substation, by months, for the growing season, 1909 to 1914, inclusive. 



[Data (in °F.) from the records of the Biophysical Laboratory of the Bureau of Plant Industry.] 





Apr. 



May. 





June. 





July. 



Sea- 



Year. 



Mean. 



Maxi- 

 mum. 



Mini- 

 mum. 



Mean. 



Maxi- 

 mum. 



Mini- 

 mum. 



Mean. 



Maxi- 

 mum. 



Mini- 

 mum. 



Mean. 



Maxi- 

 mum. 



Mini- 

 mum. 



sonal 

 mean. 



1909 



35 

 50 



42 

 45 

 47 

 48 



62 

 92 

 89 

 68 

 89 

 79 



9 



12 

 12 

 19 

 19 

 10 



51 

 51 

 56 

 54 

 52 

 54 



86 

 81 

 90 

 85 

 95 

 86 



20 

 25 

 15 

 31 

 22 

 20 



61 

 67 

 68 

 64 

 67 

 62 



91 

 105 



100 

 99 

 95 

 92 



40 

 32 

 43 

 32 

 41 

 39 



67 

 68 



65 

 65 

 67 

 73 



94 

 104 

 99 

 90 

 93 

 100 



47 

 43 

 38 

 38 

 40 

 44 



54 



1910 



59 



1911 



58 



1912 



57 



1913 



58 



1914 



59 







Average 



. 



53 



65 



68 



58 











1"" 









EXPERIMENTAL METHODS. 



In all the varietal tests at Williston the primary objects have been 

 to determine the relative yielding powers of the varieties and to 

 increase the yield and quality through the selection of standard 

 varieties or the importation of new ones. 



The work has been conducted along the two lines usual on experi- 

 ment farms: (1) Testing in field plats under conditions that conform 

 as closely as possible to farm practices, and (2) testing in nursery 

 rows, where a very much larger number of varieties or races can be 

 grown more economically than is possible in large plats. 



The work of testing and improving cereals has included both spring 

 and winter varieties, but the greater part of the work has been with 

 spring cereals 



PLAT EXPERIMENTS. 



DIMENSIONS OF PLATS. 



The field tests were conducted on plats approximately one-twen- 

 tieth of an acre in area. The plats have varied slightly each year in 

 size and shape, but all plats were uniform in size for each year. The 

 approximate dimensions have been 8 feet wide (the width of the drill 

 used) and 272 J feet long, but in some years they were longer and nar- 

 rower and in other years they were shorter, making an area slightly 

 more or less than one-twentieth of an acre. The alleys between the 

 plats have been 18 inches wide. A general view of the plats is 

 shown in figure 4 



TREATMENT OF PLATS. 



In 1908, the first year during which the Williston substation was 

 operated, all of the field plats were located on old ground that had 

 borne oats the previous year. The following two years, 1909 and 

 1910, the varietal plats were located on new ground and were there- 

 fore in a different location each year. In each case, the virgin soil 



