ACTION OF MANGANESE IN SOILS. 
Table TI. — Effect of manganese on growth of 'plants in a productive loam soil. 
( Untreated equals 100.) 
9 
Manganese 
(parts per 
million) . 
MnCl 2 . 
MnSO<. 
Mn(N0 3 ) 2 . 
MnCOs. 
Mn0 2 . 

100 
100 
100 
100 
100 
10 
103 
99 
104 
101 
103 
25 
100 
102 
105 
100 
99 
50 
101 
100 
100 
103 
100 
100 
102 
98 
97 
98 
102 
250 
97 
98 
98 
100 
99 
By an examination of the table it is seen that there is no apprecia- 
ble increase with any of the manganese salts. There is a slight in- 
crease in some cases and frequently a slight depression. The slight 
differences may be due to experimental errors ; at least it seems fair 
to conclude that manganese has no beneficial effect on this loam soil, 
which is already productive. 
Investigators have invariably found that the action of manganese 
was different on different soils. The beneficial effects secured in 
most of the experiments were when the manganese was applied to 
a deteriorated soil. This was especially so in the work of Katayama x 
and Kakehi and Baba, 2 who secured large increases. On the other 
hand, Gregoire, Hendrick, and Carpiaux, 3 among others who worked 
with manganese on a rich soil, noticed no beneficial action. 
MANGANESE IN AQUEOUS EXTRACTS OF SOILS. 
Further studies were made on manganese salts in the aqueous 
extracts of good and poor soils. The effect on growth was noted 
and the oxidizing power of the plant roots in the solution as influ- 
enced by manganese salts received especial attention. 
Some interesting work has been done with the action of manganese 
in aqueous solutions. Aso 4 found that manganese stimulated growth 
of radish, barley, wheat, and peas in nutrient solution when added 
in amounts of 20 parts per million. He showed that the plants grown 
in solution containing manganese yielded a juice which has a more 
powerful oxidizing power than the plants without manganese. A 
yellowing of the leaves of the manganese plants occurred and the 
roots turned dark. Bertrand 5 had observed that the ash of oxidizing 
enzymes contain manganese and that in the presence of manganese 
the oxidizing effect of these enzymes is greatly increased. 
» Bui. Col. Agr. Tokyo, 7, 91 (1906-1908). 
« Bui. Col. Agr. Tokyo, 7, 455 (1906-1908). 
a Bui. Agr. (Brussels), 23, 388 and 764 (1907). 
4 Aso, K., On the physiological influence of manganese compounds on plants. 
6,177(1902-3). 
&Compt.rend., 124, 1032 (1897). 
25873°— 14 2 
Bui. Col. Agr., Tokyo, 
