LaMotte STH Series - Manual (Page 19)

Ferric Iron
The role of iron in plant nutrition is discussed in the LaMotte Soil
Handbook. Iron is essential to the formation of chlorophyll, and
iron deficiency causes chlorosis. While most soils contain
abundant iron, only a fraction is soluble and readily available to
the growing plant. This is particularly true in neutral or alkaline
soils. Acid soils contain higher levels of available iron.
Procedure:
1. Use a transfer pipet (0364) to transfer four drops of the
general soil extract to one of the larger depressions on a spot
plate (0159).
2. Use the 0.05 g spoon (0696) to add one level measure of
*Iron Reagent Powder (5275). Mix with a clean stirring rod
(0519).
3. Add one drop of *Ferric Iron Test Solution (5116PS). Mix
again.
4. Match the resulting color to the *Ferric Iron Color Chart
(1348). The test result is read in pounds per acre ferric iron.
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