2 BULLETIN 42, U. S. DEPARTMENT OF AGRICULTURE. 
per cent MnO, the average content being 0.071 (instead of 0.20 per 
cent given in the circular). 
This element is universally found in plants, frequently in relatively 
large quantities, exceeding often that of the related element iron. In 
the ash of beech leaves was found in one case 11.25 per cent Mn 3 4 
and only 1.07 per cent Fe^g. 1 Manganese has been found in the 
various organs; young shoots and leaves are especially rich in the 
element. 2 The conifers have a higher per cent than have leaf-bearing 
trees. One case has been reported where 35 per cent was found in 
the ash of pine needles and 41 per cent in the ash of pine bark. 3 
Kelley 4 has reported the analysis of a large number of plants grown 
on two different soils. The ash of these vary in manganese content 
from a trace in the case of wheat straw to 1.70 per cent Mn 3 4 in 
pineapple leaves grown on normal soil. Of plants grown on soil high 
in manganese content, the analysis showed the ash of wheat straw to 
contain 0.22 per cent and pineapple leaves to contain 2.41 per cent, 
the highest quantity being in the leaves of Waltlieriaamericana, which 
contained 8.70 per cent Mn 3 4 . While manganese is found universally 
distributed in plants and exists in most soils, it is recognized that it 
does not serve directly in a plant-food capacity. Plants have been 
raised in water cultures to perfection in the absence of any added 
manganese. Nevertheless, manganese salts have been frequently 
recommended in soil work for the increase of crop production, either 
as soil amendment or fertilizer, although its action is neither well 
understood nor its effects on crop yield very definitely determined, 
the results in the literature being often contradictory. Its recent 
prominence as a catalytic fertilizer makes a knowledge of its action 
in soils of considerable interest. 
REVIEW OF EARLIER EXPERIMENTS WITH MANGANESE IN SOIL 
CULTURE. 
The study of the effect of manganese on growth has been made 
almost entirely in foreign countries. The application of manganese 
compound in soil culture has given widely different results. In 
some cases there were beneficial actions, in others harmful, and in 
a large number of the experiments the results were negative. 
Of the various forms of manganese, the sulphate and chloride have 
been used most by investigators. Xagaoka 5 working with the cul- 
ture of rice in frames in paddy fields found that manganese sulphate 
added at the rate of 25 kilos of aIii 3 4 per hectare (about 20 pounds 
i Wolff, E.,loc.cit., 1,121. 
2 Pichard. Comp. rend., 126, 550 (1898). 
1 Schroder, T., Forstchemische und pflanzenphysiologische Untersuchungen, Thorand, 1878. 
* Kelley, W. P., The function and distribution of manganese in plants and soils. Bui. 26, Hawaii Expt. 
Sta. (1912). 
5 Nagaoka, M., On the stimulative action of manganese upon rice. Bui. Col. Agr. Tokyo, 5, 469 
(1902-3); 6, 135 (1904-5); 7, 77 (1906-1908). 
