Lysimeter Experiments 



29 



The combined transpiration and evaporation from the planted tanks 

 may be estimated by subtracting the average annual percolation for 

 all the planted tanks from the average annual rainfall. . This has been 

 termed the evapo-transpiration of the crops, and from this may be cal- 

 culated the evapo-transpiration ratio, as appears in table 11: 



TABLE 11. Evapo-Transpiration for All Crops Raised during Five-Years Period 



Rainfall 



Percolation from- planted tanks . 



Transpiration and evaporation from planted tanks . 



Liters 

 per tank 



1,311.6 

 697.8 



613.8 



Evapo-transpiration ratio . 1 : 580 



The actual transpiration ratio for all the crops raised during the five- 

 years period was therefore somewhere between 1 : 290 and 1 : 580. The 

 crops raised were maize, oats, wheat, timothy, clover, and mixed grasses. 



In table 12 is given a statement of the minimum transpiration ratio 

 and the evapo-transpiration ratio for each crop raised during each year, 

 with the exception of the wheat in 1912, which cannot be used for this 



TABLE 12. Moisture Relations of the Crops on Tanks 3 to 12 during the Period 



from 1910 to 1914 



Year 



1910 

 1910 

 1911 

 1911 

 1912 

 1913 

 1913 



1913 

 1914 

 1914 



1914 



Tanks 



3, 5, 7, 9, 11, 12 



6, 10 



3, 5, 7, 9, 11, 12 



6, 10 



6, 10 



3, 7, 11, 12 



5, 9 



6, 10 



3, 7, 11, 12 



5, 9 



6, 10 



Crop 



Maize 



Oats 



Oats 



Mixed grasses. . . 

 Mixed grasses. . . 



Timothy •. . 



Timothy and 



clover 



Mixed grasses. . . 



Timothy 



Timothy and 



clover 



Mixed grasses . . . 



Minimum 



tran- 

 spiration 



ratio 



1:112 

 1:189 

 1:211 

 l.oGS 

 1:G64 

 1.333 



1:363 



l:26r, 

 1:398 



1:397 

 1:408 



Evapo- 

 tran- 

 spiration 

 ratio 



1:318 

 1:646 

 1:720 

 1:1415 

 I : 1068 

 1:479 



1:477 



1:428 

 1:536 



1:509 

 1:539 



Tran- 

 spiration 

 and 

 evaporation 

 (acre 

 inches) 



18.78 

 17.14 

 14 . 33 

 16.88 

 12.10 

 10.71 



13.54 



8.61 



13.66 



15.98 

 14.49 



Dry 



matter 



in crops 



(pounds 



per 



acre) 



13,393 

 6,008 

 4,519 

 2,701 

 2,535 

 5,071 



6,393 

 4,519 



5,787 



7,110 

 6,063 



Rainfall 



in 

 percolate 

 (per cent) 



40.41 

 45.62 

 52.72 

 44.30 

 64.50 

 63.02 



53.24 

 70.27 

 55.67 



48.13 

 52.97 



29 



