22 



BULLETIN 1004, TJ. S. DEPARTMENT OF AGRICULTURE. 



Table 3. — Quantity of water used by the toJieat crop, etc. — Continued. 

 [The column headed "Ratio" shows the number of pounds of water used by the crop per pound of total yield.] 



Station and year. 



Water used. 



Yield. 



From 

 the soil. 



Precipi- 

 tation. 



Total. 



Grain. 



Straw. 



Total. 



Inches. 



Inches. 



Inches. 



Bushels. 



Pounds. 



Pounds. 



1.74 



12.96 



14.70 



22.7 



1,920 



3,280 



3.24 



13.56 



16. 80 • 



23.0 



3,060 



4,440 



3.16 



4.59 



7.75 



6.8 



1,000 



1,410 



- .08 



1.55 



1.47 















5.74 



3.32 



9.06 



12.8 



1,790 



2,560 



3.57 



5.60 



9.17 



6.0 



1, 600 



1,960 



-1.66 



18.12 



16.46 



22.7 



2,310 



3,670 



3.26 



6.72 



9.98 



17.2 



2,440 



3,470 



3.35 



6.35 



9.70 



4.2 



1,290 



1,540 



3.56 



10.66 



14.22 



15.5 



3,370 



4,300 



2.21 



11.24 



13.45 



14.3 



1,590 



2,540 



1.26 



3.94 



5.20 



2.9 



480 



660 



4.69 



11.32 



16.01 



21.3 



2,760 



4,040 



.86 



4.51 



5.37 



4.8 



660 



950 



4.71 



5.50 



10.21 



22.2 



2,530 



3,860 



3.79 



11.18 



14.97 



26.3 



1,740 



3,320 



2.76 



5.04 



7.80 



9.3 



1,140 



1,700 



.45 



9.26 



9.71 



2.1 



560 



690 



.90 



5.35 



6.25 















3.25 



6.98 



10.23 



3.5 



1,010 



1,220 



5.15 



4.12 



9.27 



1.5 



1,290 



1,380 



4.20 



8.79 



12.99 



17.5 



1,950 



3,000 



2.44 



2.24 



4.68 















— .36 



5.61 



5.25 















2.41 



7.05 



9.46 















.86 



3.60 



4.46 















.83 



4.03 



4.86 















6.23 



10.41 



16.64 



7.8 



1,280 



1,750 



4.23 



10.41 



14.64 



8.4 



690 



1,200 



2.61 



8.08 



10.69 



4.0 



760 



1,000 



- .97 



8.68 



7.71 















2.39 



11.01 



13.40 



7.3 



1,070 



1,510 



5.79 



4.25 



10.04 



6.3 



630 



1,010 



7.66 



4.17 



11.83 



12.4 



1,800 



2,550 



1.81 



4.21 



6.02 



1.7 



480 



580 



1.11 

 1.28 



3.73 

 3.91 



4.84 

 5.19 





 





 





 



1.88 



9.53 



11.41 



13.5 



1,010 



1,820 



6.95 



4.80 



11.75 



5.6 



685 



1,020 



2.14 



1.98 



4.12 















Ratio. 



North Platte: 



1908 



1909 



1910 



1911 



1912 



1914 



1915 



1916 



1917 



1919 



Akron: 



1909 



1911 



1912 



1913 



1914 



1915 



1916 



Garden City: 



1909 



1911 



1912 



1914 



1915 



1916 



Dalhart: 



1909 



1910 



1911 



1913 



1914 



Dalhart, new field: 



1914 



1915 



Amarillo: 



1909 



1911 



1912 



1915 



1917 



1918 



Tucumcari: 



1913 



1914 



1915 



1916 



1,014 



856 



1.244 



801 

 1,059 

 1,015 



651 

 1,426 



749 



1,199 

 1,783 



897 

 1,279 



599 

 1,021 

 1,039 



3,185 



1,898 



1,520 



980 



2,152 



2,761 

 2,420 



2,009 

 2,250 

 1,050 

 2,349 



1,419 

 2,607 



Study of Table 3 shows that, at least so far as the individual sta- 

 tions are concerned, a definite relation exists between the total quan- 

 tity of water used and the yield of grain, straw, and total weight per 

 acre. This relation is not always consistent, but it must be borne in 

 mind that when crops are subjected to the varying conditions that 

 occur in the field a very close correlation is impossible, and any 

 strong correlation, either positive or negative, is highly significant. 



It will be noted from the study of all the stations that high yields 

 are always associated with high water use. A high water use does 

 not necessarily mean a high yield, because the crop may suffer either 

 through poor distribution of rain or through some extreme climatic 

 condition that limits the yield. On the other hand, a high yield 

 necessitates a high use of water. Table 3 contains data on the use of 

 water by 96 wheat crops. Twenty of these crops yielded more than 

 20 bushels of grain per acre. Only one of these consumed less than 

 11.5 inches of water. At Akron, Colo., in 1914, a yield of 22.2 bushels 



