6 



BULLETIN 103&, U. S. DEPARTMENT OF AGRICULTUEE. 



proximately the growing period for the cereals on dry land at Newell. 

 The seasonal precipitation was a prominent factor affecting the yields 

 of grain. The monthly, seasonal, and annual precipitation recorded 

 in inches at the Belle Fourche Farm from 1908 to 1919, inclusive, is 

 shown in Table I. The seasonal and annual precipitation is also 

 shown graphically in figure 2. 



Tablk I. — Monthly, seasmial, and annual precipitation at the Belle Fourche 

 Experiment Parra, 1908 to 1919, inclusive. 



[Depth of precipitation in inches. T^trace.] 



Year. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



March 



to 

 July, 

 inclu- 

 sive. 



Total. 



190S 



00.20 

 a. 17 

 .73 

 .13 

 .24 

 .57 

 T 

 .92 

 .36 

 .92 

 .99 

 .04 



00.19 

 0.23 

 .70 

 .05 

 .10 

 .24 

 1.00 

 1.01 

 .23 

 .74 

 .64 

 ..57 



al.65 

 a. 19 

 .93 

 .09 

 .71 

 .99 

 .29 

 .16 

 .98 

 .27 

 .81 

 .87 



1.16 



.84 

 1.57 



.17 

 2.32 



.25 

 1.09 

 2.58 



.64 

 2.51 

 2.40 

 2.14 



3.95 

 3.87 

 1.26 

 .45 

 2.26 

 1.98 

 2.22 

 2.32 

 3.17 

 3.71 

 1.60 

 1.14 



1.47 

 5.59 

 1.51 



.50 



.29 

 3.10 

 2.09 

 4.74 

 2.19 



.97 

 1.17 



.35 



1.26 

 2.45 

 1.42 



.80 

 3.20 



.35 

 1.34 

 5.74 

 2.01 



.80 

 3.41 

 2. .59 



0.62 



. 55 



1.03 



1.86 



2.80 



.26 



1.12 



.44 



2.02 



1.67 



2.99 



1.02 



0.52 

 1.07 

 2.92 



.92 

 3.49 

 2. .38 



.35 

 1.26 



.20 



.35 

 3.08 

 1.20 



O2.10 



.76 



.27 



.39 



.51 



1.86 



1.77 



1.25 



.99 



.46 



.22 



2.49 



00.20 

 .73 

 .11 

 .98 

 .04 

 .10 

 

 .43 

 .33 

 T 

 .15 

 1.22 



00.91 

 1.28 

 .10 

 .30 

 .13 

 .45 

 .43 

 .17 

 .28 

 .92 

 .85 

 .62 



9.49 

 12.94 

 6.69 

 2.01 

 8.78 

 6.67 

 7.03 

 15.54 

 8.99 

 8.26 

 9.39 

 7.09 



14.23 



1909 



17.73 



1910 



12.55 



1911.; 



6.64 



1912 



16.09 



191.3 



12.53 



1914 



11.70 



1915 



21.02 



1916 



13.40 



1917 



13.32 



1918 



18.31 



1919 



14. 25 







Average — 



.44 



.48 



.66 



1.47 



2.33 



2.00 



2.11 



1.37 



1.48 



1.09 



.36 



.54 



8.57 



14.31 



"■ From records of the United States Weather Bureau at Vale and Orman, S . Dak. 



RELATION OF PRECIPITATION TO YIELDS OF GRAIN. 



The limiting factor in crop production at Xewell usually has been 

 the moisture supply. Winter grains have been subject to cold in- 

 jury, so that the yields may depend on several factors. The yields 

 of spring grains, however, are closely associated with the amount 

 and distribution of the rainfall. The precipitation during the grow- 

 ing period is the most important. The amounts and distribution of 

 this seasonal precipitation have largely determined the yields of 

 spring grain on the dry land at Newell. In some seasons, as that of 

 1912, the rains came too late to benefit the early varieties of grain. 

 In 1910, 1917, and 1919 the lack of moisture during the heading and 

 ripening period caused low yields. 



A rain of less than 0.3 inch during the growing season, unless 

 followed or preceded by other rains within 24 hours is of almost no 

 value to grain crops in this section. The moisture from light rains 

 does not penetrate far into the soil and is soon evaporated. In 1911 

 there was a total precipitation of 2.01 inches during the growing 

 season, March to July, inclusive, but this came in such small and 

 scattered showers that it was useless for crop production. Conse- 

 quently all grains were a failure that year. 



