546 
Vol. XXI, No. 8 
Journal of Agricultural Research 
different flasks. The seeds were germinated in sphagnum moss or in 
thoroughly leached coconut fiber. When the plumules were about i y 2 
inches long the seedlings were transferred to the nutrient solutions. 
Two or three Erlenmeyer flasks joined together at the necks and 
covered with black cloth were used as containers for the nutrient solu¬ 
tions. One seedling was grown in each of these double or triple flasks 
for a period of 20 days. The plants were started in 200-cc. flasks, but 
as they became larger they were transferred successively to 500-cc. and 
1,000-cc. flasks. By guiding the new roots into the proper flasks, the 
roots of each plant were kept equally divided between the two or three 
nutrient solutions afforded the plant. 
The nutrient solutions were renewed six times during the 20-day 
period of each experiment, and transpired water was replaced daily. 
While the plants were small the solutions were changed every 4 days; 
later the solutions were changed every 3 days, and finally every 2 days. 
The frequent renewals of the solutions and the large size of the flasks 
insured an ample supply of the nutrients. 
Rain water, caught on the roof of the glasshouse, was used in making 
up the nutrient solutions. It contained only 17 parts per million of 
total solids (organic and inorganic) and was, therefore, sufficiently pure 
for these experiments. In these experiments it was necessary only to 
guard against appreciable contamination with nitrogen, phosphoric 
acid, and potash. The compositions of the nutrient solutions used in 
the different tests are given in Table I. 
Tabus I .—Composition of nutrient solutions used 
Chemical. 
Com¬ 
plete 
solution. 
Solution 
lacking 
nitro¬ 
gen. 
1 Solution 
lacking 
phos¬ 
phorus. 
l Solution 
lacking 
potas¬ 
sium. 
Solution 
lacking 
nitrogen 
and 
phos¬ 
phorus. 
Solution 
lacking 
nitrogen 
and 
potas¬ 
sium. 
Solution 
lacking 
phos¬ 
phorus 
and 
potas¬ 
sium. 
Solution 
lacking 
nitrogen, 
phos¬ 
phorus, 
and 
potas¬ 
sium. 
Monopotassium phosphate 
(KH 2 PO 0 . 
Gm. 
7.14 
Gm. 
7.14 
Gm. 
Gm. 
Gm. 
Gm. 
Gm. 
Gm. 
Monosodium phosphate 
(NaHzPOO. 
10. 06 
10. 05 
Potassium nitrate (KNO3)... 
Sodium nitrate (NaNQ?). 
Calcium nitrate (Ca(NC>3) 2 
4 H 2 0 ).. 
14- 40 
9. 18 
12.78 
14 - 40 
9. 18 
12. 78 
4 - 56 
2. 44 
!. 
15. 20 
21.14 
Potassium sulphate (K2SO4).. 
12.40 
19. 86 
11. 84 
16. 96 
19. 83 
11.84 
| 
Sodium sulphate (Na 2 SC>4 
ioH 2 0 ). 
3- 16 
11.60 
11. 84 
19. 85 
11.84 
19. 85 
11.84 
Calcium chlorid (CaCl 2 6 H 2 0 ) 
Magnesium chlorid (MgCl 2 
6 H 2 0 ). 
4 * 50 
4 - 50 
4 - So 
2. 66 
5- oo 
20. 00 
Magnesium sulphate (MgSOi 
7 H 2 0 ). 
4. 06 
5- 00 
20. 00 
4.06 
5.00 
20.00 
4.06 
5- 00 
4.06 
5-oo 
4.06 
5 -oo 
20. 00 
Ferric tartrate (F&CCtHjOs^ 
+h 2 o). 
Calcium carbonate, precipi¬ 
tated, (CaCOs). 
S-oo 
20. 00 
5- 00 
20. 00 
Water. 
20. 00 20. 00 
100.000 cc. 
