MANGANESE CHLOROSIS OF PINEAPPLE. O 
stimulation led to reduction processes being predominant. Large applications 
of manganese have been found injurious, undoubtedly because of excessive 
stimulation and excessive oxidation in microorganisms and in the plant, with a 
resulting change in the biochemical activities of plant and microorganisms and 
in the conditions of inorganic and organic soil constituents, the ultimate result 
of which change is injurious to the growing crop. 
Later in 1916, Skinner and Reid (J$) found that the productivity 
of the soil was increased by manganese when the plats on which the 
experiments were conducted were limed. They state that — 
The action of manganese in the acid soil was probably to stimulate the life 
processes in the soil, acting on the organic matter in such a way as to produce 
changes which resulted in a lessened crop-producing power, while its action in 
the neutralized soil was such as to stimulate oxidation and other biological 
processes, acting on the organic soil constituents and producing changes favor- 
able to the growing plants. 
Pugliese {37) from water-culture experiments similar to those of 
Loew and Sawa suspected an antagonism between iron and man- 
ganese anil stated that there was an optimum ratio which he gave 
as 1 : 2..J. 
McCool {36) found that- 
Pure solutions of manganese salts are extremely poisonous to pea and wheat 
seedlings. The degree of toxicity is greatly reduced by full nutrient solutions 
and by soil cultures. The injurious action of the manganese ion is manifested 
mainly toward the tops of plants. Chlorosis of the leaves is the first indication 
of an overdose of manganese. Manganese is less injurious to plants grown in 
the dark than to those grown in the light. Calcium, potassium, sodium, and 
magnesium ions are each effective in counteracting the poisonous action of 
manganese. Mutual antagonism exists between the manganese ion and each of 
the following: Potassium, sodium, and magnesium. 
Tottingham and Beck (4-0 suspected an antagonism toward iron 
similar to those stated above for potassium, sodium, and magnesium. 
Brown and Minges (9) in 1916 believed that the effects of manga- 
nese applications to the soil may be ascribed to their effect on ammo- 
nification and nitrification. 
Funchess (IS) found that the nitrification of dried blood on certain 
Alabama soils produced soluble manganese salts which were toxic in 
effect. 
Deatrick {12) found in high concentrations that manganese salts 
exerted a toxic effect, and in lower concentrations marked stimulation. 
"The toxic influence results in the browning of the roots and the 
bleaching of the leaves." 
PREVIOUS INVESTIGATIONS ON LIME-INDUCED CHLOROSIS. 
It has been known for many years that some plants become affected 
with chlorosis or bleaching when they are grown on soils containing 
very large amounts of carbonate of lime. Some species of grape- 
vines which grow on certain highly calcareous soils of France are 
probably the best-known examples of chlorosis. This bleaching has 
been attributed by some investigators to lack of potash in the soil 
or to the physical condition of the soil, but the general conclusion 
seems to be that the condition is brought about by lack of iron in 
the plants, due to excessive amounts of carbonate of lime in the soil. 
Manganese has not been associated with this condition. 
Gile and Ageton {16) have probably made the latest and most 
thorough investigation of such highly calcareous soils. In 1911 Gile 
