ACTION OP MANGANESE IN SOILS. 
17 
The effect of manganese was also tested in the extract of Sassafras 
sandy loam taken from a productive field. In this test the manga- 
nese was used in concentrations of 20 parts per million. The chloride, 
sulphate, nitrate, carbonate, and dioxide were used. The experiment 
ran from November 12 to November 27. The results are given in 
Table VIII. 
Table VIII. — Effect of manganese on growth and oxidation in productive Sassafras sandy 
loam. ( Untreated = 100.) 
Treatment. 
Relative 
growth. 
Relative 
oxidation. 
100 
79 
90 
88 
95 
105 
100 
Extract+MnCl2 
125 
Extract+MnSO* 1 
106 
Extract+Mn(N0 3 ) 2 
120 
Extract+MnC0 3 
150 
Extraet+Mn0 2 
200 
The effect of the various manganese salts on this good soil was to 
increase the oxidation by the plants; the growth, however, was even 
decreased. The experiment was repeated with the same soil and 
same manganese salts. The plants grew from December 1 to Decem- 
ber 14. The results are given in Table IX. 
Table IX. — Effect of manganese on growth and oxidation in 
loam. ( Untreated — 100.) 
productive Sassafras sandy 
Treatment. 
Relative 
growth. 
Relative 
oxidation. 
Extract untreated 
100 
82 
90 
95 
90 
92 
100 
Extract+MnCh 
106 
Extract+MnSO* 
100 
Extract+Mn(N0 3 ) 2 
116 
Extract+MnC0 3 
140 
Extract+Mn0 2 
150 
Again it is shown that manganese is not beneficial to this good soil. 
In both experiments the oxidation by the plants was increased by 
addition of the salts. Other experiments were made with this soil, 
using varying amounts of several salts of manganese. The action, 
however, was similar to those recorded above. There was no stimu- 
lation of growth with any of the salts varying in amount from 5 to 
100 parts per million. In each of the tests with this soil the plants 
were affected, and after 10 days' growth the tips became yellow and the 
leaves showed indications of drying up. These effects are the result 
of excessive oxidation and probably show the cause of the harmfulness 
of manganese in this and certain other good soils. The oxidizing power 
of plants in these productive soils was already good, and they needed 
nothing to stimulate this function. When manganese was added 
the oxidation was increased and became even too great, thus causing 
a harmful action. 
