ASTM D2976-71(1998)

Standard Test Method for pH of Peat Materials

SCOPE
1.1 This test method  covers the electrometric measurement of the pH of peat materials. It is a means of expressing the degree of acidity or alkalinity of peat material suspended in water and 0.01 M calcium chloride solution.  
1.2 This standard does not purport to address the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Dec-1998
• ICS: 65.080 - Fertilizers
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.22 - Media for Plant Growth

Relations

• Replaced By: ASTM D2976-71(2004) - Standard Test Method for pH of Peat Materials (Withdrawn 2013)
• Effective Date: 01-Jul-2004
• Referred By: ASTM F3339-20 - Standard Guide for Construction or Renovation of Native-soil Athletic Fields
• Effective Date: 10-Dec-1998
• Referred By: ASTM D8198-18 - Standard Specification for Hydraulically Applied 100 % Wood Fiber Mulches
• Effective Date: 10-Dec-1998
• Referred By: ASTM F2747-19 - Standard Guide for Construction of Sand-based Rootzones for Golf Putting Greens and Tees
• Effective Date: 10-Dec-1998
• Referred By: ASTM F2396-11(2019) - Standard Guide for Construction of High Performance Sand-Based Rootzones for Athletic Fields
• Effective Date: 10-Dec-1998
• Referred By: ASTM D4427-23 - Standard Classification of Peat Samples by Laboratory Testing
• Effective Date: 10-Dec-1998
• Referred By: ASTM D8202-18 - Standard Specification for Hydraulically Applied 100% Wheat Straw Fiber Mulches
• Effective Date: 10-Dec-1998

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D 2976 – 71 (Reapproved 1998)
Standard Test Method for
pH of Peat Materials
This standard is issued under the fixed designation D 2976; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope where such specifications are available. Other grades may be
2 used, provided it is first ascertained that the reagent is of
1.1 This test method covers the electrometric measurement
sufficiently high purity to permit its use without lessening the
of the pH of peat materials. It is a means of expressing the
accuracy of the determination.
degree of acidity or alkalinity of peat material suspended in
5.2 Purity of Water—Water shall be carbon-dioxide-free
water and 0.01 M calcium chloride solution.
distilled water. Use water with a pH of not less than 6.5 nor
1.2 This standard does not purport to address all of the
more than 7.5 obtained by boiling distilled water 15 min and
safety concerns, if any, associated with its use. It is the
cooling under carbon dioxide-free conditions.
responsibility of the user of this standard to establish appro-
5.3 Acid Potassium Phthalate Buffer Solution (0.05 M)—
priate safety and health practices and determine the applica-
Dissolve 10.21 g (dried1hat 105°C) of potassium phthalate
bility of regulatory limitations prior to use.
(NBS Standard Samples) in water and dilute to 1 L. Protect the
2. Summary of Test Method solution against evaporation and contamination with molds.
Replace the solution when mold is apparent. The effect of
2.1 The electrometric measurement of the pH of peat in
temperature is as follows:
suspensions of water and calcium chloride solutions is made
°C pH
with a potentiometer using a glass-calomel electrode system,
calibrated with buffers of known pH.
5 to 24 4.00
25 to 33 4.01
3. Significance and Use
34 to 37 4.02
3.1 pH measurements are made in water and in calcium
5.4 Calcium Chloride, Stock Solution (1.0 M)—Dissolve
chloride solution because the pH readings in water can be
147 g of CaCl ·2H O in distilled water in a 1-L volumetric
2 2
modified by salts such as fertilizer material whereas the
flask, cool, dilute to volume with distilled water, and mix.
observed pH in calcium chloride solution is virtually indepen-
Dilute 15 mL of this solution to 200 mL with distilled water in
dent of the initial amount of salts present in the soil. pH values
a volumetric flask, and standardize by titrating a 25-mL aliquot
obtained in calcium chloride solution usually run about a 0.5 to
of the diluted solution with standard 0.1 N silver nitrate
0.8 pH unit lower than measurements in water due to release of
(AgNO ) solution using 1 mL of 5 % potassium chromate
more hydrogen ions by cation exchange.
(K CrO ) solution as the indicator.
2 4
5.5 Calcium Chloride Solution (0.01 M)—Dilute 20.0 mL of
4. Apparatus
stock 1.0 M CaCl solution to 2 L with distilled water. The pH
4.1 pH Meter—Potentiometer equipped with glass-calomel
of this solution should be between 5 and 6.5.
electrode system. Follow the manufacturer’s instructions for
5.6 Phosphate Buffer Solution (0.025 M)—Dissolve 3.40 g
the pH meter used.
of KH PO and 3.55 g of Na HPO (NBS Standard Samples
2 4 2 4
186-I and II) in water and dilute to 1 L. Dry salts2hat 130°C
5. Reagents
before use. Effect of temperature on pH is:
5.1 Purity of Reagents—Reagent grade chemicals shall be
°C pH
used in all tests. Unless otherwise indicated, it is intended that
0 6.98
all reagents shall conform to the specifications of the Commi
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