TIME OF PLOWING SMALL-GRAIN/ STUBBLE. 



Bureau and the Bureau of Plant Industry. A study of these records 

 shows the great variation in monthly and annual precipitation. 

 The experimental data following are for the past six years, 1909 to 

 1914, inclusive. In two of these years the precipitation has been 

 above the normal, as determined from the entire record. In 1909 

 the total was 2.2 inches less than the recorded maximum. In four 

 years of the six it has been below normal, the precipitation of 1911 

 being the minimum recorded. Thus, in the six years we have had 

 nearly the maximum and the minimum amounts of water that may 

 be expected. 



A heavy monthly precipitation usually means that a considerable 

 amount falls at one time and penetrates to a depth where it is not 

 lost by evaporation but can be used by plants. The exceptions to 

 this are when the precipitation falls as torrential showers with a high 

 percentage of run-off and shallow penetration, or when it comes as 

 light snow, which is blown off. A light monthly precipitation indi- 

 cates that the greater part of it falls as light showers or as snow 

 flurries. Under such distribution most of the moisture is lost by 

 evaporation and very little, if any, penetrates deeply enough in the 

 soil to be held until used by the plants. 



Table I. — Monthly and annual precipitation and normal monthly and annual precipi- 

 tation at Akron, Colo., 1905 to 1914, inclusive. 



[Precipitation record, in inches, for the years 1905 to 1909, inclusive, from the reports of the United States 



Weather Bureau.] 



Year. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Total. 



1905 



0.37 



.25 











T. 



.05 



0.32 

 .26 



i T. 



.34 

 1.38 



.16 



5.45 



1.51 



.43 



T. 



3.06 



.26 



4.55 

 4.22 

 1.74 

 1.70 

 .40 

 3.96 



4.37 

 3.32 

 3.30 

 3.57 

 1.87 

 2.06 



2.14 

 1.20 

 3.26 

 2.35 

 3.32 

 1.38 



3.82 

 2.46 

 6.06 

 3.40 

 4.61 

 1.47 



0.86 

 1.26 

 5.13 

 1.62 

 3.77 

 3.72 



0.83 

 1.00 

 1.86 

 .22 

 2.16 

 3.81 



1.73 



1.90 



.02 



3.20 



.78 

 .05 



0.12 

 1.56 

 1.00 

 2.00 

 .48 

 .12 







0.08 

 .60 

 T. 

 .55 

 .32 



24.56 



1906 



19.02 



1907 



23.40 



1908 



18.38 



1909 



22.38 



1910 



17.36 



1911 



.60 



.44 



.06 



2.63 



1.15 



1.48 



1.34 



1.30 



2.40 



1.47 



.28 



1.36 



14.51 



1912 



.28 



1.43 



.78 



2.49 



2.86 



3.39 



3.58 



1.58 



1.88 



1.99 



.18 



.29 



20.73 



1913 



.22 



.40 



1.57 



2.19 



1.44 



1.35 



1.85 



1.14 



2.08 



.34 



.30 



3.67 



16.55 



1914 



.03 



.32 



.20 



4.01 



1.46 



3.54 



1.66 



1.05 



.23 



2.08 



.10 



.90 



15. 58 



Normal* 



.18 



.51 



1.33 



2.79 



2.54 



2.34 



3.02 



2.14 



1.65 



1.36 



.61 



.78 



19.25 



J T.«= Trace. 



2 Normal precipitation, October to March, inclusive, is 24.8 per cent of the normal for the year. 



In the consideration of the time of plowing, the great variation in 

 time and amount of precipitation must be kept in mind. The winter 

 precipitation is usually in the form of snow, and wind is an important 

 factor in its local distribution. Heavy rainfall or snows that are not 

 disturbed by wind may occur between November I and April 1, but 

 b the ground is usually frozen the amount of moisture stored in the 

 soil from them apparently would not be affected by the time of 

 plowing. Generally, the greater part of the snowfall will be blown 

 off of b fall-plowed field, while a considerable quantity will be held 

 i ibble bind. 



