4 
Tue Errect or MANGANESE COMPOUNDS ON SOILS AND PLANTS 375 
other than in experimentation and as a fertilizer complementary to the 
usual chemical fertilizers.”” Masoni (1916) experimented with several 
manganese salts. Althothe chloride and the sulfate seemed to give 
a certain advantage, he believed the results were too small to indicate 
definitely the specific effect on the growth of the plants tested. Ehren- 
berg and Schultze (1917) state that experiments covering several years 
show that under many sorts of conditions neither a favoring nor an inhibi- 
tory action of manganese compounds on the growth of plants is de- 
monstrable. At the Woburn station, however, Voelcker (1904) observed 
that manganese iodide, applied at the rate of 50 pounds to the acre, was 
very toxic to the growth of barley. 
On the other hand, some surprising results have been obtained from 
the use of manganese salts. Javillier (1908) states that comparatively 
small quantities of this element have been sufficient to increase the yields 
of certain crops from 25 to 50 per cent. He believes there is no doubt 
that manganese compounds, particularly the sulfate, may be used advan- 
tageously as a complementary manure. Loew and Honda (1904—05) report 
an increase of 50 per cent in Cryptomeria japonica from fertilizmg with 
manganese sulfate. With the use of the same salt Ray and Pradier (1909) 
were able to increase the yield of apricots 23 per cent. Bartmann (1910) 
cites Marre as having secured an increase of 60 per cent in some crops. 
Numerous other investigators have reported data indicating that man- 
ganese is a fertilizer of decided value. 
A number of investigators,.including Nagaoka (1906-08), and Skinner 
and his co-workers (1914, 1916), report data which are apparently con- 
tradictory. Nagaoka (1906-08) reported that in 1902 manganese sulfate 
applied at the rate of 70 pounds to the.acre, increased the yield of rice 
37 per cent; the following year the residual effect was considerable; in 
1904 the season was ‘ exceptionally favorable,’ but the treated plats 
again surpassed the checks; in 1905 the experiment was repeated, but that 
year the yield was greatly decreased. Skinner and Sullivan (1914) 
reported their work on the action of manganese in soils; they found that 
the growth of wheat was increased when various salts were added to a 
soil described as an unproductive sandy loam, while on a productive loam 
the salts had no stimulating effect. 
_ Further experiments were reported by Skinner and Reid (1916), who 
state that “in a six-years field test of manganese sulphate used at the 
