19201 



WALSTER— BARLEY 



103 



Solution C 

 (lacking in phosphorus) 



3-437 gm. KNO3 



8.8561 gm. KC1 

 23.855 gm. Ca(N0 3 ) 2 , 4 H 2 

 19.789 gm. MgS0 4 , 7H 2 



Solution D 

 (phosphorus in one-fourth concentration) 



Solution F 

 (nitrogen in one-fourth concentration) 



0.8592 gm. KNO3 



2 .0422 gm. KC1 

 14.6923 gm. KH 2 P0 4 

 19 . 7890 gm. MgS0 4 , 7H 2 



4. 1432 gm. Ca(N.0 3 ) 2 , 4H 2 



9 . 264 gm. CaCl 2 , 2H 2 



14.6923 gm. KH 2 P0 4 

 12-353 g m - CaCL, 2H 2 

 19.789 gm. MgS0 4 , 7H 2 



0.8592 gm. KNO3 



2. 1 67 1 gm. NaN0 3 



3.873 gm. KH 2 P0 4 

 12.8019 gm. Na 2 HP0 4 , i2H 2 

 19.789 gm. MgS0 4 , 7H 2 

 23.8558 gm. Ca(N0 3 ) 2) 4 H 2 



To certain of the AB cultures extra doses of N, K, and P, 

 alone, and in all possible combinations, were added in the amounts 

 and at the times indicated in the schematic outline. These extra 

 doses were supplied in the form of solutions of NaN0 3 , KC1, and 

 Na 2 HP0 4 , i2H 2 respectively. All cultures were run in triplicate. 

 Certain of the replicates in each set of triplicates received a modified 

 supplementary treatment, as indicated in table II, the letters N, K, 

 and P indicating NaN0 3 , KC1, and Na 2 HP0 4 , i2H 2 respectively. 



Oderbrucker barley (Wisconsin No. 5) was seeded March 1. 

 About 30 seeds were sown per culture, the cultures being thinned to 

 25 plants per culture. This heavy seeding was purposely chosen in 

 order to prevent tillering, so that the course of development of a 

 plant with a single culm could be followed. 



Temperature and humidity control. — The temperature of 

 the greenhouses was controlled by means of automatic thermo- 

 regulators. The lower temperature selected was 15 C, the higher 

 temperature 20 C. The degree of control obtained is shown in 



