THe EFrect oF MANGANESE COMPOUNDS ON SOILS AND PLANTS 385 
grams to a basket. The baskets were paraffined and a sand mulch was 
placed on the surface. Six baskets of each treatment were set up, four 
of which were planted with wheat seedlings about 10 centimeters high. 
There were four seedlings in each basket. The baskets were carried to 
the greenhouse, where they remained for a period of three months. Dur- 
ing that period they received such applications of distilled water, from 
time to time, as would bring the soil up to the original moisture content 
of 25 per cent (dry basis). On May 3, 1916, the crop was harvested, 
tand the plants were dried, weighed, and analyzed for manganese. The 
results are given in table 7: 
TABLE 7. Wueat Grown ror THree Montus on DuNnEIRK Sitt Loam TREATED WITH 
MANGANESE SULFATE 
Average weight . 
Parts per million of manganese added _ of seedlings Relative 
in each culture weights 
(grams) 
OM. Se MOANA eos kes 2.70 100 
Qee o's os theo a Se ee ee ee eee en aren MT yeh Os) 120 
i Eee ee re cs pan ie Me, oes heres 2.80 104 
NQORPINEE es ct SCRE Sop ey helo sa es Ae 1.94 72 
AVI 22 ao Se ke 2.05 76 
An examination of the relative weights shows that the manganese is 
at least not prevented entirely from stimulating plant growth when it 
is added to soil. The stimulation at 10 parts per million was appre- 
ciable. 
Another set of cultures was arranged on December 12, 1916. Two kilo- 
grams of air-dry soil, to which the various quantities of manganese sulfate 
were added, was placed in wire baskets. These baskets then received a 
coating of paraffin and a-sand mulch. Seven of the baskets received an 
application of calcium carbonate at the rate of 20,000 parts of CaO per 
million of soil. The soil was seeded to wheat and the moisture content 
was raised to 25 per cent (dry basis), where it was kept by the addition 
of distilled water from time to time. One month later the seedlings were 
thinned to five to a basket, and these were allowed to grow for seven and 
