18 
BULLETIN 42, TJ. S. DEPARTMENT OF AGRICULTURE. 
The experiments with the different soils recorded above were made 
at different times of the year and, as the action of the manganese and 
growth of the plants might be influenced by some climatic conditions, 
an experiment was next made in which both poor and good soils 
were simultaneously tested. Six soils of different character were 
selected. 
Three of these soils were very poor and unproductive and three 
were good productive soils. Soils Nos. 1, 2, and 3 are unproductive. 
Soil No. 1 is a sandy clay collected from a park where the lawn was 
very poor. No. 2 is a sandy loam soil from a cultivated field. No. 3 
is a clay loam taken from under a tree, where repeated attempts to 
grow a lawn had failed. 
Soils Nos. 4, 5, and 6 are productive soils taken from fields which 
were growing good crops. No. 4 is a loam, No. 5 a sandy loam, and 
No. 6 a silt loam. 
Extracts were made and plants grown in each at the same time. 
Manganese in the form of chloride and sulphate were used in amounts 
of 20 and 50 parts per million of the element manganese. The 
experiment was conducted from April 5 to April 19. The results 
are given in Table X. The growth and oxidation are compared with 
the untreated soil extract in each case. 
Table X. — Effect of manganese on oxidation and growth in unproductive and productive 
soil extracts. Results expressed in relative oxidation and growth. ( Untreated = 100.) 
Unproductive soils. 
Productive soils. 
1 
2 
3 
4 
5 
6 
Treatment. 
Sandy clay. 
Sandy loam. 
Clay loam. 
Loam. 
Sandy 
loam. 
Silt loam. 
1 
a 
o 
| 
o 
S 
o 
i 
"3 
o 
♦a 
1 
| 
-a 
O 
% 
o 
O 
| 
X 
O 
4 
o 
O 
d 
o 
X 
O 
100 
126 
119 
130 
137 
100 
142 
156 
135 
172 
100 
102 
101 
114 
107 
100 
111 
118 
120 
130 
100 
112 
122 
114 
108 
100 
180 
190 
130 
127 
100 
99 
76 
94 
98 
100 
180 
175 
130 
135 
100 
90 
93 
96 
88 
100 
125 
156 
142 
160 
100 
106 
76 
100 
83 
100 
Extract+MnCl 2 , 20 parts 
per million 
150 
Extract+MnCl 2 , 50 parts 
132 
Extract+MnS0 4 , 20 parts 
100 
Extract 4-MnS0 4 , 50 parts 
114 
The results of this test substantiate those of previous experiments. 
The effect of the manganese on the unproductive soils was to increase 
the oxidation and growth. There was an increase with both salts of 
manganese and both concentrations. This, however, is reversed in 
the case of the productive soils. The oxidation is increased with each 
of the solutions, while the growth was depressed. The effect of exces- 
