ASTM D2973-23

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2973 − 22 D2973 − 23
Standard Test Method for
Total Nitrogen in Peat Materials
This standard is issued under the fixed designation D2973; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers a chemical test method for the determination of the mass percent of nitrogen in peat material.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.3 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
1.3.1 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as the industry
standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not
consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives;
and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations.
It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.
1.4 Warning—Mercury has been designated by many regulatory agencies as a hazardous material that can cause serious medical
issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Caution should be taken
when handling mercury and mercury containing products. See the applicable Safety Data Sheet (SDS) for additional information.
Users should be aware that selling mercury and/or mercury containing products into your state or country may be prohibited by
law.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D1193 Specification for Reagent Water
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.22 on Media for Plant Growth.
Current edition approved June 15, 2022Nov. 1, 2023. Published June 2022November 2023. Originally approved in 1971. Last previous edition approved in 20162022 as
D2973–16. DOI: 10.1520/D2973-22.–22. DOI: 10.1520/D2973-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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D2973 − 23
D2974 Test Methods for Determining the Water (Moisture) Content, Ash Content, and Organic Material of Peat and Other
Organic Soils
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction
Materials Testing
D6026 Practice for Using Significant Digits and Data Records in Geotechnical Data
3. Terminology
3.1 Definitions:
3.1.1 For definitions of common technical terms used in this standard, refer to Terminology D653.
4. Summary of Test Method
4.1 In general terms, the nitrogen is converted into ammonium salts by destructive digestion of the specimen with a hot, catalyzed
mixture of concentrated sulfuric acid and potassium sulfate. These salts are subsequently decomposed in a hot alkaline solution
from which the ammonia is recovered by distillation and finally determined by acidimetric titration.
4.2 Specifically, a representative specimen is obtained from a representative sample and is air dried following Method B of D2974.
A portion of the air dried specimen is put in a flask along with mercuric oxide, potassium sulfate, and sulfuric acid. The flask is
gradually heated to a boil. After boiling and cooling, water, potassium sulfide solution, zinc, and sodium hydroxide solution are
added. The flask is connected to the digestion bulk/condenser and the flask is heated. Finally, sulfuric acid mixed with an indicator
is titrated into the flask until the end point is reached.
5. Significance and Use
5.1 Nitrogen content is important as it is one of the primary plant food elements necessary for plant growth. Nitrogen content of
peat is necessary to make sure an adequate, but not excessive amount of fertility is supplied to the target plant. Nitrogen is present
in peat as organic nitrogen, and therefore, does not release nitrogen to plants as quickly as chemical fertilizers. However, nitrogen
from peat continues to be released for several years as the organic matter decomposes.
5.2 This information is particularly useful to people working in industries where plant health, sustainability, and viability are
important.
NOTE 1—The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the
equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective
testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself ensure reliable results.
Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.
6. Apparatus
6.1 For Digestion—Use Kjeldahl flasks of hard, moderately thick, well-annealed glass with total capacity of about 800 mL.
Conduct digestion over a heating device adjusted to bring 250 mL of Type III water at 25°C to a rolling boil in about 5 min.
6.2 For Distillation—Use 800-mL Kjeldahl flasks fitted with rubber stoppers through which passes the lower end of an efficient
scrubber bulk or trap to prevent mechanical carry-over of sodium hydroxide solution during distillation. Connect the upper end
of the bulb tube to the condenser tube by rubber tubing. Trap the outlet of the condenser in such a way as to make sure complete
absorption of ammonia distilled over into the acid in the receiver.
6.3 Erlenmeyer Flask—A glass flask having a capacity of 250 or 300 mL.
6.4 Oven—A thermostatically controlled oven capable of maintaining a uniform temperature of 110 6 5°C throughout the drying
chamber.
D2973 − 23
6.5 Balance—Balances shall conform to the requirements of Guide D4753 and having a readability without estimation to 0.01 g
for water content determinations and 0.001 g for mass determinations. The capacity of the balance shall exceed the mass of the
container plus specimen.
6.6 Mortar and Pestle (Optional)—Apparatus suitable for crushing soft lumps.
6.7 Glass Cylinder—A cylinder with an indication mark at 1,000 6 5 mL.
6.8 Miscellaneous Items—Items such as spatulas, dishes, stirring rods, glassware of appropriate sizes with graduations, gloves, eye
protection, protective clothing, and wash bottle may be usef
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