WATEE REQUIREMENT OF ALFALFA. 



Table I . — Dry-viatter 'production and water consumption of alfalfa as affected by frequent 

 cutting, at Akron, Colo., in 1912. 





Series A: Grimm alfalfa,A.D.I., 





Series B: Grimm alfalfa, A.D.I., 





E-23-20-52 ( Medicago sativa). 





E-23-20-52 ( Medicago 



sativa). 











Water 









Water 



Period of growth. 







Water 



ab- 

 sorbed. 



require- 



Period of growth. 









require- 





Pot 



Dry 



ment 





Pot 



Dry 



ab- 

 sorbed. 



ment 





No. 



matter. 



based 

 on dry 





No. 



matter. 



based 

 on dry 











matter. 











matter. 







Grams. 



Kilos. 









Grams. 



Kilos. 







f 133 



131.6 



89.6 



680 





145 



53.3 



33.1 



621 





134 



121.4 



73.9 



609 





146 



89.3 



54.7 



612 



May 24 to July 26.. 



1 135 

 i 136 



141.0 

 140.6 



82.4 

 72.5 



584 

 516 



June 3 to July 26.. 



147 

 148 



59.8 

 78.3 



37.5 

 50.5 



627 

 645 





137 



141.4 



79.8 



564 





149 



100.6 



60.5 



602 





I 138 



118.0 



76.6 



649 





I 150 



91.0 



53.0 



582 





600± 17 



615±6 





f 133 



131.7 



118.8 



902 





f 145 



20.6 



22.5 



1,092 





134 



110.0 



93.0 



845 



July 26 to Sept. 7. 



146 



25.7 



25.1 



974 



July 26 to Sept. 6.. 



135 

 136 



138.6 

 133. 3 



112.4 

 115.8 



810 

 870 



Cropped Aug. 3, 

 10, 17, 24, 31, and 



147 

 148 



26.8 

 32.3 



25.2 

 28.4 



941 

 880 





137 



135.2 



108.1 



800 



Sept. 7. 



149 



23.7 



25.7 



1,088 





I 138 



120.2 



107.4 



893 





I 150 



30.3 



26.4 



872 





853 ±13 



975±23 





f 133 



73.7 



35.4 



479 





f 145 



34.7 



15.6 



450 





134 



64.7 



28.1 



434 





146 



37.1 



16.5 



445 



Sept. 6 to Nov. 4. . 



135 



136 



80.7 

 82.0 



32.4 

 32.0 



401 

 390 



Sept. 7 to Nov. 4. . 



147 



148 



38.8 

 35.0 



19.8 

 16.4 



510 

 467 





137 



83.8 



36.1 



431 





149 



39.3 



20.1 



571 





I 138 



79.5 



31.1 



391 





I 150 



38.3 



16.4 



428 





421 ±10 



479±16 





f 133 



337.0 



243.8 



724 





f 145 



108.6 



71.2 



655 





134 



296.1 



195.0 



658 





146 



152.1 



96.3 



633 



Combined cut- 



135 



360.3 



227.2 



632 



Combined cut- 



147 



125.4 



82.5 



658 



tings, May 24 



136 



355.9 



220.3 



620 



tings, June 3 to 



148 



145.6 



95.3 



654 



to Nov. 4. 



137 



360.4 



224.4 



623 



Nov. 4. 



149 



163.6 



106.3 



650 





I 138 



317.7 



215.1 



678 





I 150 



159.6 



95.8 



600 





656±11 



642±6 













Summary. 



Period of growth. 



Total dry matter 

 produced (6 pots). 



Total water ab- 

 sorbed (6 pots). 



Water require- 

 ment. 





Series A. 



Series B. 



Series A. 



Series B. 



Series A. 



Series B. 



May 24 to July 26 ' 



Grams. 

 794.0 

 769.0 

 464.4 



Grams. 

 472.3 

 159.4 

 223.2 



Kilos. 

 474.8 

 655.5 

 195.1 



Kilos. 

 289.3 

 153.3 

 104.8 



600 ±17 

 853 ±13 

 421±10 



615±6 



July 26 to Sept. 6 



Sept. 6 to Nov. 4 



975±23 

 479 ±16 



Combined 



2, 027. 4 



854.9 



1,325.8 



547.4 



656±11 



642±6 



1 Series B was replanted June 3. 



During the second period the water requirement of the check series 

 was 853 ± 13, while the series which was cut weekly during this period 

 gave a water requirement of 975 ±23, an increase of 14 ±4 per cent. 

 It thus appears that alfalfa is slightly less efficient in the use of water 

 when subjected to weekly cuttings. 



During the third period, when both sets were again treated alike, 

 the water requirement of the check series (A) was 421 ±10 and that 

 of series B 479 ±16. The B series thus shows during the third period 

 also a slight increase (14 ±4 per cent) in water requirement com- 

 pared with series A, which may be the result of the weakening of the 



