ACTION OF MANGANESE IN SOILS. 7 
of the investigators, however, have given detailed description of the 
composition and character of the soil. A good deal of evidence has 
been secured by Kelly * and others which tends to show that the 
effect, whether beneficial or harmful, is an indirect one. The results 
show in a general way that manganese is beneficial to certain trees 
and leguminous crops and is harmful to root crops. It also seems 
that manganese is not stimulating to growth when applied to an 
acid soil. 
EXPERIMENTS WITH MANGANESE SALTS IN POTS. 
The effect of manganese salts was tested on soils in paraffined wire 
pots according to the method described in Circular 18 of the Bureau 
of Soils. Wheat was the plant used as the test crop. The soil was 
weighed out in pans and treated with the various manganese salts 
in different amounts and allowed to stand in a moist condition for a 
week before planting. Five pots were used for each treatment and 
six wheat plants grown in each pot. The wheat was grown in the 
greenhouse for a month and then was cut and the weight of the 
green plant taken. Five pots of untreated soil were included in the 
experiment as a check. The increase or decrease in weight of the 
treated plants over the untreated was taken as the effect of the 
manganese. 
The soil used in this experiment was a sandy loam, which was 
unproductive in the field, and did not respond well to general fertili- 
zers. Five manganese salts were worked with, each in £y& different 
concentrations, namely 10, 25, 50, 100, and 250 parts per million 
of Mn. The salts tested were the chloride, sulphate, nitrate, carbo- 
nate, and dioxide of manganese. The salts were dissolved or sus- 
pended in water and applied to the soil. It was thoroughly mixed 
by sifting and after one week was put in the pots and planted to 
wheat. The wheat came up uniformly and grew well. Table 1 
gives the relative growth due to the various treatments. The 
growth in the untreated soil is taken as 100 and the figures, there- 
fore, represent relative green weight. The plants grew from Sep- 
tember 30 to November 6. 
Table 1. — Effect of manganese on growth of wheat plants in an unproductive sandy loam 
soil. Untreated taken as 100. 
Manganese 
(parts per 
MnCl 2 . 
MnSO<. 
Mn (NOs)s. 
MnC0 3 . 
Mn0 2 . 
million). 

100 
100 
100 
100 
100 
10 
119 
122 
116 
111 
108 
25 
129 
121 
121 
119 
104 
50 
131 
101 
101 
100 
110 
100 
115 
122 
100 
91 
111 
250 
103 
116 
103 
89 
104 
1 Loc. cit. 
