LaMotte STH Series - Manual (Page 26)

Plant Tissue Test Procedures
Follow the soil test procedures for nitrate nitrogen, phosphorus,
and potassium, using the tissue extract in place of the general soil
extract. Remember that the color charts should only be used in a
comparative manner, along with the relative values suggested.
The most meaningful test results will be obtained from the
comparison of healthy plant and problem plant test reactions.
Guidelines for Interpreting Plant Tissue Tests
Test Factor Test Reaction
Relative Amount of
Nutrient in Plant
Tissue
Nitrate Nitrogen Dark Pink Color Abundant
Light Pink Color Adequate
Colorless
No Reserve/
Probably Deficient
Phosphorus Deep Blue Color Abundant
Light Blue Color Adequate
Yellow to Colorless Low to Deficient
Potassium Heavy Precipitate Adequate to Abundant
Medium Precipitate Low to Deficient
Trace Precipitate Deficient
No Precipitate Very Deficient
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