LaMotte STH Series - Manual (Page 22)

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 deficiency.
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 deficient 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 sufficient
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.
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.
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