398 BE. P. Deatrick 
TABLE 18. Errect or MANGANESE SULFATE AND 20.000 Parts PER MILLION oF CaLciuM 
CARBONATE ON NITRIFICATION OF AMMONIUM SULFATE IN DUNKIRK Sitt Loam 
(Cultures incubated for thirty days) 
Nitrates, 
average of 
4 cultures Relative 
(parts per amounts 
million 
of soil) 
Parts per million of manganese added 
aT G33 ir RY CR Err UR eee 344 100 
OO Sari de ces See Ree eee Re eke. cc bine ae shee Bre oe ees 32 95 
1 OOO) cSt bs vy cn Recast Sc ake een ha ee eee 273 79 
Conclusions 
The experimental data here reported seem to justify the following 
conclusions: 
1. Manganese salts added to water cultures affect the growth of wheat 
seedlings. The comparison of relative weights shows that when presented 
to the plant in high concentrations, both the sulfate and the chloride 
exert a toxic effect. In lower concentrations, manganese causes a marked 
stimulation. 
2. The degree of toxicity is reduced by full nutrient solutions and the 
reduction is directly proportional to the concentration of the nutrient 
salts. Likewise, the food stored in the endosperms reduces the toxicity 
of the plant poiscn. 
3. The toxic influence results in the browning of the roots and the 
bleaching of the leaves. The yellow leaves of the manganese plants 
contain more manganese than do the green ones. 
4, Manganese salts added to soil form manganese dioxide in proportion 
to the basicity of the soil, and thus develop a power to oxidize organic 
matter as shown by the oxidation of aloin or phenolphthalin. 
5. Manganese sulfate in water cultures stimulates the oxidizing power 
of the roots of wheat seedlings. 
6. Low concentrations of manganese sulfate were found to stimulate 
the ammonification of dried blood in soil. The nitrification of ammonium 
sulfate was inhibited. 
