EQUIPMENT

4 mL plastic autoanalyzer vials.

REAGENTS

Hydrochloric Acid: HCl

Sulfuric Acid: H2SO4

MEHLICH I EXTRACTING SOLUTION

Dilute 162 mL, hydrochloric acid and 28 mL sulfuric acid to 40 liters with deionized water and mix well.

PROCEDURE

  1. Scoop 5 g soil into a 40 mL extraction bottle.
  2. Add 20 mL Mehlich I extracting solution.
  3. Shake for 5 minutes on a shaker at high speed (250 oscillations per minute).
  4. Filter using Whatman #1 paper.
  5. Pour the extracts into the 4 mL plastic autosampler vials, using the same order as in the procedure described on page 7.
  6. Analyze on the ICP Emission Spectrograph.
  7. Alternatively, analyze for K, Ca, Mg, Zn, and Mn by the atomic absorption method (pp 46-48) and analyze for P by the AutoAnalyzer colorimetric method (pp 49-51).

REFERENCES

  1. Mehlich, A. 1953. Determination of P, Ca, Mg, K, Na, and NH4. North Carolina Soil Test Division (Mimeo 1953).
  2. Nelson, W. L., A. Mehlich, and E. Winters. 1953. The Development, Evaluation, and Use of Soil Tests for Phosphorus Availability. In W. H. Pierre and A. G. Norman (eds). Soil and Fertilizer Phosphorus Vol. II. Agronomy A Series of Monograph, pp 153-188.
  3. Perkins, H. F. 1970. A Rapid Method of Evaluating the Zinc Status of Coastal Plain Soils. Comm. in Soil Sci. and Plant Anal. 1:35-46.