| Abstract: | Abstract The effect of including charcoal during extraction on the amount of manganese brought into solution was measured on soils from the Coastal Plain, Piedmont, and Mountain physiographic regions. The presence of charcoal increased the level of Mn extracted with dilute acid by a factor of 1.23 for soils with less than 40 ppm extractable Mn. This value was used to adjust the interpretation of the manganese soil test for soybeans based on previous correlation data so that charcoal may be omitted if desired. |
