LaMotte SMART 3 Electronic Soil Lab - Manual (Page 53)

SMART3 Soil 1.11 53
ELECTRONIC TEST METHODS
pH 
PROCEDURE
Use the 10 g Soil Measure (1164) to add one level measure of the soil 1.
sample to a 50 mL beaker (0944). Use the graduated cylinder (0416) to add
10 mL of deionized water. Stir thoroughly.
Let stand for at least 30 minutes, stirring two or three times.
2.
Stir mixture just prior to making the pH reading. Determine the pH reading 3.
of the sample by following the instructions for the pH Meter.
LIME REQUIREMENT - WOODRUFF METHOD 
PROCEDURE
Use the 10 g Soil Measure (1164) to add one level measure of the soil 1.
sample to a 50 mL beaker (0944). Use the graduated cylinder (0416) to add
10 mL of deionized water. Stir thoroughly.
Let stand for at least 15 minutes.
2.
Add 20 mL of Woodruff Buffer Solution (5272). Mix well, and let stand for at 3.
least 20 minutes, stirring two or three times.
Take reading using the pH meter. Stir mixture just prior to making reading.
4.
Each 0.1 pH unit drop from pH 7.0 indicates a lime requirement equivalent 5.
to 1000 lbs calcium carbonate (CaCO
3
)/acre.
Test P
rocedures