LaMotte IRON, ALUMINUM, & SULFATE MODULE D - Manual (Page 2)

EXTRACTION PROCEDURE
1. Fill a test tube (0755) to line 7 with *Universal Extracting Solution (5173).
2. Use the 0.5 g spoon (0698) to add four level measures of soil to the test tube. Cap
and shake for one minute.
NOTE: When adding samples with high concentrations of carbonates to
*Universal Extracting Solution (5173), swirl tube to mix for 30 seconds before
capping to allow gases to escape.
3. Fold a piece of fi lter paper (0465) in half, then in half again. Press corners
together to form a cone. Place in funnel (0459). Pour extract solution into funnel,
collecting extract. This clear extract is used for the test.
IRON TEST
1. Use a transfer pipet (0364) to add four drops of clear fi ltrate to a large depression
on a spot plate (0159).
2. Use the 0.05g spoon (0696) to add one level measure of *Iron Reagent Powder
(5275). Stir with a stirring rod (0519).
3. Use pipet (0392) to add one drop of *Ferric Iron Test Solution (5116). Stir with a
stirring rod (0519).
4. Match sample color to a color standard on the Ferric Iron in Soil Color Chart
(1348). Record as pounds per acre Ferric Iron.
INTERPRETATION OF FERRIC IRON TEST
Most soils will contain iron in suffi cient quantities to satisfy the needs of most
plants. A defi ciency of iron is sometimes noted in alkaline soils, and is indicated by a
chlorotic condition of the plants. High tests may be obtained on acid soils.