504 
Vol. VII, No. 12 
Journal of Agricultural Research 
Upland rice seedlings germinated over distilled water were placed in 
the nutrient solutions when the plumules were about 2 inches long. 
Water distilled from a cast-iron still with a block-tin condenser and stored 
in a tin-lined copper tank was used in the nutrient solutions. The plants 
were grown for 40 days in Erlenmeyer flasks of Jena or Nonsol glass. 
Flasks of 200 c. c. capacity were used for the first 25 days of each experi¬ 
ment and flasks of 500 c. c. capacity for the remaining 15 days. Tran¬ 
spired water was replaced with distilled water daily, and the plants were 
changed to fresh solutions every 4 days, except they were left in the solu¬ 
tion 6 days before the first change.. The plants were kept in a wire in¬ 
closure (five meshes to the inch) during fair weather and in a glass house 
during rains. 
The nutrient solutions used were of the following compositions: 
Acid solution. Gm. 
Potassium nitrate (KN 0 3 ) 10. 71 
Monobasic potassium 
phosphate (KH 2 P 0 4 )... 7. 14 
Sodium nitrate (NaN 0 3 ).. 21. 43 
Sodium sulphate (Na 2 S 0 4 ) 3.15 
Calcium ‘chlorid (CaCl 2 ).. 2. o 
Magnesium chlorid 
(MgCl 2 ). 2.0 
Sulphuric acid (H 2 S 0 4 )... o. 245 
Distilled water. 100,000 
N eutral solution. Gm. 
Potassium nitrate (KN 0 3 ) 10. 71 
Monobasic potassium 
phosphate (KH 2 P 0 4 ) . . 3. 57 
Dibasic potassium phos¬ 
phate (K 2 HP 0 4 ). 3. 57 
Sodium nitrate (NaN 0 3 ).. 21. 43 
Sodium sulphate (N^SOJ 3.15 
Calcium chlorid (CaCl 2 ).. 2. o 
Magnesium chlorid 
(MgCl 2 ).. 2.0 
Distilled water... 100,000 
The solution alkaline with carbonate of lime was the same as the neutral 
solution except for the addition of 0.41 gm. of precipitated calcium car¬ 
bonate per liter. In the various experiments different quantities and 
kinds of iron were added to these solutions. 
It is possible that the above solutions are not ideal for rice, although 
plants equal in size to exceptionally large field plants were grown in them. 
Previous and subsequent work with these solutions showed that the growth 
of rice was not increased by increasing the quantity of calcium chlorid 
or magnesium chlorid, by doubling the quantities of dibasic pdtassium 
phosphate and monobasic potassium phosphate, or by doubling the 
quantities of potassium nitrate and sodium nitrate. The concentration 
of total salts in the solutions was lower than usual, but afforded sufficient 
nutrients because of the frequent changes. There is an advantage in 
using dilute solutions in that imperfect balancing of the salts (antago¬ 
nistic effects of the ions) may produce no injury in low concentrations. 
Before each change the nutrient solutions were made up fresh from a 
stock solution and the iron added 18 hours before the plants were inserted. 
After emptying out the old solution, the flasks and roots were rinsed once 
with a small quantity of distilled water. These details seem unimportant, 
but, as will be seen later, alteration in such apparently trivial details may 
affect the results. 
