Aug. is, 1921 
Effect of Ammonium Sulphate upon Plants 
7i5 
reaction in these solutions produced by the plants during the various 
intervals throughout the growth period. The data of this table, which 
agree in a general way with the corresponding data of Table V, are 
fairly representative of similar data for all the cultures of the respective 
series in this experiment. They further emphasize the point already 
brought out, that the different forms of iron here used have little if any 
effect upon the plants with respect to their influence upon the hydrogen- 
ion concentration of the nutrient media, except in so far as differences 
in size and vigor of the plants or differences in the extent of the absorbing 
surfaces of the root systems may produce somewhat corresponding 
differences in the magnitudes of the changes in reaction. On the other 
hand, the different forms of iron used in either of the two types of solu¬ 
tions here used produced markedly different effects upon the general 
appearance, health, and vigor of the plants and upon the growth rates, 
as will be more fully brought out by a further consideration of the dry- 
weight yields of tops and roots. 
Table VI.—P H values of the culture solutions of the Tottingham series (A) and the 
ammonium-sulphate series ( B) supplied with iron in the form of ferrous sulphate 
Tottingham series (A). 
Ammonium-sulphate series (B). 
Culture No. 
Ini¬ 
tial. 
High¬ 
est. 
Low¬ 
est. 
Avei 
age. 
Ini¬ 
tial. 
High¬ 
est. 
Low¬ 
est. 
Aver¬ 
age. 
T1R1C1. 
4.8 
6. 0 
4.8 
5 - 42 
4 - 
8 
4 - 7 
4. 4 
4 - 59 
C 3 . 
4.8 
6.6 
5 - 0 
5 - 97 
4 - 
8 
5 - 0 
4 - 5 
4 - 74 
£5 . 
4. 8 
6.6 
5 -o 
5 - 96 
4 . 
8 
4. 7 
4.4 
4. 60 
C 7 . 
4.8 
6.3 
4.9 
5 - 65 
4 - 
9 
4-8 
4. 4 
4- 63 
R3 c i . 
4-8 
6 -3 
4-9 
5 - 7 2 
4 - 
8 
4.9 
4 - 4 
4 . 53 
£3 . 
4. 8 
6. 6 
5 - 0 
6. 03 
4 - 
9 
4- 6 
4. 4 
4 - 53 
^5 . 
4.8 
6.6 
5- 0 
5 - 9 6 
4 - 
8 
4 . 7 
4. 4 
4. 60 
R5C1. 
4.8 
6. 6 
4. 9 
5 - 98 
4 . 
9 
4 - 7 
4. 4 
4. 61 
C3. 
4.8 
6. 6 
4. 9 
6. 03 
4. 
9 
4.8 
4. 4 
4 - 59 
R7C1. 
4.8 
6.6 
5 - 0 
5 - 96 
4 . 
9 
5 - 1 
4. 4 
4. 71 
T3R1C1. 
4.7 
5-9 
4. 6 
5 - 33 
4 - 
7 
4 . 7 
4. 4 
4 - 55 
£3. 
4. 6 
6.3 
4. 6 
5 - 59 
4 . 
7 
4.7 
4. 4 
4 - 5 6 
^5 . 
4 . 7 
6. 0 
4 - 7 
5 * 48 
4 - 
7 
4 . 7 
4-3 
4 - 55 
R3C1. 
4 . 7 
6 -3 
4 - 7 
5. 60 
4- 
7 
4 . 7 
4. 4 
4 - 53 
^3 . 
4 - 7 
6 -3 
4. 6 
5 - 54 
4 - 
7 
4. 6 
4. 4 
4 - 54 
R5 Ci . 
4 - 7 
6-5 
4-9 
5.81 
4 - 
7 
4.6 
4. 4 
4 - 54 
T5R1C1. 
4. 6 
5 - 9 
4 - 5 
5. 28 
4 - 
7 
4. 6 
4. 4 
4 . 54 
C3 . 
4. 6 
5-8 
4. 6 
5-32 
4 - 
6 
4 - 7 
4. 4 
4 - 5 6 
R3 Ci . 
4-7 
6. 2 
4. 6 
5 * 50 
4 - 
6 
4. 6 
4. 4 
4 - 54 
T7R1C1. 
4. 6 
5-9 
4. s 
5 - 37 
4 - 
6 
4.7 
4. 4 
4 - 5 6 
Shive’s R5C2. 
4. 6 
5- 6 
4. 6 
tr. OO 
Tottingham’s T3R1C4. 
4. 6 
%) 
K. 
4. 6 
o* w y 
K. 06 
