ASTM_D_2973_-_16.pdf

Designation:D297316Standard Test Method forTotal Nitrogen in Peat Materials1This standard is issued under the fixed designation D2973;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers a chemical test method for thedetermination of the mass percent of nitrogen in peat material.1.2 UnitsThe values stated in SI units are to be regardedas standard.No other units of measurement are included in thisstandard.1.3 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.3.1 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-dures used do not consider material variation,purpose forobtaining the data,special purpose studies,or any consider-ations for the users objectives;and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations.It is beyond the scopeof this standard to consider significant digits used in analysismethods for engineering design.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD1193 Specification for Reagent WaterD2974 Test Methods for Moisture,Ash,and Organic Matterof Peat and Other Organic SoilsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4753 Guide for Evaluating,Selecting,and Specifying Bal-ances and Standard Masses for Use in Soil,Rock,andConstruction Materials TestingD6026 Practice for Using Significant Digits in GeotechnicalDataE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.Terminology3.1 Definitions:3.1.1 For definitions of common technical terms in thisstandard,refer to Terminology D653.4.Summary of Test Method4.1 In this method,the nitrogen is converted into ammo-nium salts by destructive digestion of the specimen with a hot,catalyzed mixture of concentrated sulfuric acid and potassiumsulfate.These salts are subsequently decomposed in a hotalkaline solution from which the ammonia is recovered bydistillation and finally determined by acidimetric titration.5.Significance and Use5.1 Nitrogen content is important as it is one of the primaryplant food elements necessary for plant growth.Nitrogencontent of peat is necessary to make sure an adequate,but notexcessive 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 chemicalfertilizers.However,nitrogen from peat continues to be re-leased for several years as the organic matter decomposes.NOTE1The quality of the result produced by this standard isdependent on the competence of the personnel performing it,and thesuitability of the equipment and facilities used.Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc.Users of this standard arecautioned that compliance with Practice D3740 does not in itself ensurereliable results.Reliable results depend on many factors;Practice D3740provides a means of evaluating some of those factors.6.Apparatus6.1 For DigestionUse Kjeldahl flasks of hard,moderatelythick,well-annealed glass with total capacity of about 800 mL.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.22 on Soil as a Mediumfor Plant Growth.Current edition approved July 1,2016.Published July 2016.Originally approvedin 1971.Last previous edition approved in 2010 as D2973101.DOI:10.1520/D2973-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Conduct digestion over a heating device adjusted to bring 250mL of Type III water at 25C to a rolling boil in about 5 min.6.2 For DistillationUse 800-mL Kjeldahl flasks fittedwith rubber stoppers through which passes the lower end