LaMotte STH Outfit - Manual (Page 18)

18
Manganese
An essential element in the enzyme system of plants, manganese plays
a role in metabolic reactions affecting germination, photosynthesis, and
other vital aspects of plant development. Yellowing and stunted growth
results from manganese defi ciency. Some insoluble manganese is present
in all soils. Its solubility or availability is closely related to soil pH.
Calcareous soils or soils which have been heavily limed may be defi cient
in available manganese. Application of a soluble manganese salt, such as
manganese sulfate, will correct this problem. Conversely, toxic levels
of available manganese may develop in highly acid soils; this condition
may be corrected by liming. Since available manganese may be leached
from the soil or altered to less active forms by oxidation, this test should
be conducted just prior to planting and during plant growth. Any positive
test reading, even a very low reading, generally indicates the presence
of suffi cient available manganese to meet plant requirements. A high test
reading is undesirable and indicates a need for liming.
PROCEDURE
1. Use a transfer pipet (0364) to add 10 drops of soil extract to the
large depression on a spot plate (0159).
2. Use the 0.05 g spoon (0696) to add one measure of Manganese
Buffer Reagent (6310). Mix with a clean stirring rod (0519) until
the powder dissolves.
3. Use the other 0.05 g spoon (0696) to add one measure of *Manganese
Periodate Reagent (6311). Mix with a clean stirring rod for 20 seconds.
Note: The *Manganese Periodate Reagent will not dissolve completely.
4. Match the color in the spot plate to a color standard on the Manganese
in Soil Color Chart (1307-01). Record as ppm Manganese.
Note: Immediately clean the spot plate to prevent staining.