8 BULLETIN 42, U. S. DEPARTMENT OF AGRICULTURE. 
Each of the manganese salts caused a stimulation in growth in 
this soil. The degree of stimulation, however, varied with the salt 
and with the amount. Manganese chloride and sulphate seem to 
have had the most effect, the chloride causing the greatest improve- 
ment. There was an increase in this case of 31 per cent when 50 
parts per million were used. Smaller amounts caused a correspond- 
ing increase. Amounts larger than 50 parts per million were not so 
beneficial. With manganese sulphate there was an increase of 22 
per cent in amounts of 10 to 100 parts per million. The result with 
50 parts per million would seem to be abnormal or inaccurate, since 
there is shown only an increase of 1 per cent, while with 25 and 100 
parts per million the increase was 21 and 22 per cent, respectively. 
Again, 250 parts per million was not as effective as smaller amounts. 
Where manganese nitrate was used the largest improvement was 
with 25 parts per million, which gave an increase of 21 per cent. 
Amounts larger than 25 parts per million caused no appreciable in- 
crease. There was a similar effect in the case of manganese carbo- 
nate. The largest increase here was 19 per cent with 25 parts per 
million. Ten parts per million increased growth 11 per cent. Quan- 
tities higher than 50 parts per million were harmful. The dioxide 
was the least effective of the manganese salts. While there was no 
harmful action with any of the amounts used, the largest increase 
was only 11 per cent where 100 parts per million were used. 
This experiment was repeated with the same soil at a later time. 
The test was conducted in the same way as the one just described. 
The same salts were used in the same concentrations. This time 
the plants grew from November 17 to December 20. There were in- 
creases with each salt. Again the chloride and sulphate caused the 
largest increases, and the dioxide the least. The best growth was 
secured with 25 to 50 parts per million of the manganese, this being 
true with each of the salts. 
These two experiments seem to indicate that manganese in small 
quantities is beneficial on this soil. The chloride and sulphate gave 
largest increases. Twenty-five to 50 parts per milhon of the element, 
Mn, which is 12£ to 25 pounds per acre, to a depth of 6 inches, gave 
the largest growth. Applications higher than this gave no corre- 
spondingly larger increases and in some cases were even harmful. 
Another soil was worked with in a similar manner as the poor sandy 
loam just discussed. This was a clay loam soil from Pennsylvania, 
and was a productive field soil. The soil had been manured and well 
cultivated for a number of years. A four-year crop rotation had 
been practiced. The soil at the time the sample for this work was 
taken was growing a good crop of wheat. The relative green weights 
obtained in this experiment are given in Table II. The plants grew 
from January 5 to February 6. 
