SIST EN ISO 11260:2011
(Main)Soil quality - Determination of effective cation exchange capacity and base saturation level using barium chloride solution (ISO 11260:1994+Cor 1:1996)
Soil quality - Determination of effective cation exchange capacity and base saturation level using barium chloride solution (ISO 11260:1994+Cor 1:1996)
Specifies a method for the determination of the cation exchange capacity (CEC) at the pH of the soil and for the determination of the content of exchangeable sodium, potassium, calcium and magnesium in soil. Is applicable to all types of air-dried soil samples; pretreatment according to ISO 11464 is recommended. The determination of CEC as specified here is a modification of the method by Gillman.
Bodenbeschaffenheit - Bestimmung der effektiven Kationenaustauschkapazität und der Basensättigung unter Verwendung von Bariumchloridlösung (ISO 11260:1994+Cor 1:1996)
Diese Internationale Norm legt ein Verfahren zur Bestimmung der Kationenaustauschkapazität (KAK) beim pH-Wert des Bodens und zur Bestimmung des Gehalts an austauschbarem Natrium, Kalium, Calcium und Magnesium im Boden fest.
Diese Internationale Norm gilt für alle Arten von lufttrockenen Bodenproben. Die Probenvorbehandlung nach ISO 11464 wird empfohlen.
ANMERKUNG 1 Das beschriebene Verfahren wird durch Calcium gestört, das als Calcit oder Gips in der Probe vorliegt. Außerdem täuscht die Anwesenheit löslicher Salze Werte für die austauschbaren Kationen vor, die über den tatsächlich austauschbaren Mengen liegen [3]. [4].
ANMERKUNG 2 Die Bestimmung der spezifischen elektrischen Leitfähigkeit der Bodenproben nach ISO 11265 lässt erkennen, ob die Bodenproben durch lösliche Salze beeinflusst sind.
Qualité du sol - Détermination de la capacité d'échange cationique effective et du taux de saturation en bases échangeables à l'aide d'une solution de chlorure de baryum (ISO 11260:1994+Cor 1:1996)
La présente Norme internationale prescrit une méthode de détermination de la capacité d'échange cationique (CEC) au pH du sol et de la teneur en sodium, potassium, calcium et magnésium échangeables dans le sol. La présente Norme internationale porte sur tous les types d'échantillons de sol séchés à l'air, c'est-à-dire traités conformément à l'ISO 11464.
NOTES 1 La méthode décrite dépend d'interférences du calcium sous forme de calcite ou de gypse dans l'échantillon. La présence de tout sel soluble peut donc conduire à des teneurs en cations échangeables supérieures à la teneur réelle[3], [4]. 2 Le mesurage de la conductivité électrique spécifique des échantillons de sol suivant l'ISO 11265 pourrait indiquer si les échantillons de sol contiennent des sels.
Kakovost tal - Določevanje efektivne kationske izmenjalne kapacitete in stopnje nasičenosti z bazičnimi kationi z uporabo raztopine barijevega klorida (ISO 11260:1994+Cor 1:1996)
Opredeljuje metodo za določevanje kationske izmenjalne kapacitete (CEC) pri pH tal in za določevanje vsebnosti izmenljivega natrija, kalija, kalcija in magnezija v tleh. Velja za vse vrste vzorcev tal, posušenih na zraku; priporočena je preobdelava v skladu z ISO 11464. Določevanje CEC, kot je določeno tukaj, je modifikacija metode po Gillmanu.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 11260:2011
01-november-2011
.DNRYRVWWDO'RORþHYDQMHHIHNWLYQHNDWLRQVNHL]PHQMDOQHNDSDFLWHWHLQVWRSQMH
QDVLþHQRVWL]ED]LþQLPLNDWLRQL]XSRUDERUD]WRSLQHEDULMHYHJDNORULGD ,62
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Soil quality - Determination of effective cation exchange capacity and base saturation
level using barium chloride solution (ISO 11260:1994+Cor 1:1996)
Bodenbeschaffenheit - Bestimmung der effektiven Kationenaustauschkapazität und der
Basensättigung unter Verwendung von Bariumchloridlösung (ISO 11260:1994+Cor
1:1996)
Qualité du sol - Détermination de la capacité d'échange cationique effective et du taux
de saturation en bases échangeables à l'aide d'une solution de chlorure de baryum (ISO
11260:1994+Cor 1:1996)
Ta slovenski standard je istoveten z: EN ISO 11260:2011
ICS:
13.080.10 .HPLMVNH]QDþLOQRVWLWDO Chemical characteristics of
soils
SIST EN ISO 11260:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 11260:2011
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SIST EN ISO 11260:2011
EUROPEAN STANDARD
EN ISO 11260
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2011
ICS 13.080.10
English Version
Soil quality - Determination of effective cation exchange capacity
and base saturation level using barium chloride solution (ISO
11260:1994+Cor 1:1996)
Qualité du sol - Détermination de la capacité d'échange Bodenbeschaffenheit - Bestimmung der effektiven
cationique effective et du taux de saturation en bases Kationenaustauschkapazität und der Basensättigung unter
échangeables à l'aide d'une solution de chlorure de baryum Verwendung von Bariumchloridlösung (ISO
(ISO 11260:1994+Cor 1:1996) 11260:1994+Cor 1:1996)
This European Standard was approved by CEN on 3 June 2011.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11260:2011: E
worldwide for CEN national Members.
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SIST EN ISO 11260:2011
EN ISO 11260:2011 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 11260:2011
EN ISO 11260:2011 (E)
Foreword
The text of ISO 11260:1994+Cor 1:1996 has been prepared by Technical Committee ISO/TC 190 “Soil
quality” of the International Organization for Standardization (ISO) and has been taken over as EN ISO
11260:2011 by Technical Committee CEN/TC 345 “Characterization of soils” the secretariat of which is held
by NEN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by December 2011, and conflicting national standards shall be withdrawn
at the latest by December 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 11260:1994+Cor 1:1996 has been approved by CEN as a EN ISO 11260:2011 without any
modification.
3
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SIST EN ISO 11260:2011
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SIST EN ISO 11260:2011
INTERNATIONAL
ISO
STANDARD 11260
First edition
1994-08-15
Determination of effective
Soil quality -
cation exchange capacity and base
Saturation level using barium chloride
solution
Qual26 du sol - Dgtermination de Ia capacite d’khange ca tionique
effective et du taux de Saturation en bases khangeables a I’aide d’une
Solution de chlorure de baryum
Reference number
ISO 11260:1994(E)
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SIST EN ISO 11260:2011
ISO 11260:1994(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national Standards bodies (ISO member bodies). The work
of preparing International Standards is normally carried out through ISO
technical committees. Esch member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 11260 was prepared by Technical Committee
ISODC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil
characteristics.
Annexes A and B of this International Standard are for information only.
0 ISO 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
microfilm, without Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland
Printed in Switzerland
ii
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SIST EN ISO 11260:2011
INTERNATIONAL §TANDARD 0 ISO ISO 11260:1994(E)
Soil quality - Determination of effective cation
exchange capacity and base Saturation level using
barium chloride Solution
ISO 3696: 1987, Water for analytical laboratory use -
1 Scope
Specifica tion and tes t me thods.
This International Standard specifies a method for the
ISO 11265: 2) Soil quality - Determination of the
determination of the cation exchange capacity (CEC)
specific electriial conductivity.
at the pH of the soil and of the determination of the
content of exchangeable sodium, potassium, Calcium
2) Soil quality - Pretrea tment of sam-
ISO 11464:
and magnesium in soil.
ples for physik-chemical analyses.
This International Standard is applicable to all types
of air-dried soil samples; pretreatment according to
ISO 11464 is recommended.
3 Principle
NOTES
The determination of CEC as specified in this Inter-
1 The method described suffers from interference from
national Standard is a modification of the method
Calcium as calcite or gypsum in the Sample. Also, the pres-
ence of any soluble salts gives values for the exchangeable proposed by Gillman [SI. The CEC of soil samples is
cations that are higher than the actual exchangeable
determined at the pH of the soil and at a low total
amounts 131, 141.
ionic strength (about 0,Ol mol/l).
2 Measurement of the specific electrical conductivity of
The soil is first saturated with respect to barium by
the soil samples according to ISO 11265 will indicate if the
treating the soil three times with a 0,l mol/1 barium
soil samples are affected by salt.
chloride Solution. Thereafter, the soil is equilibrated
with a 0,Ol mol/1 barium chloride Solution. Subse-
quently, a known excess of 0,02 mol/1 magnesium
sulfate is added. All the barium present, in Solution as
well as adsorbed, is precipitated in the form of highly
2 Normative references
insoluble barium sulfate and, consequently, the sites
with exchangeable Ions are readily occupied by
The following Standards contain provisions which,
magnesium. The excess magnesium is determined
through reference in this text, constitute provisions
by flame atomic absorption spectrometry (FAAS).
of this International Standard. At the time of publi-
cation, the editions indicated were valid. All Standards
lt is also possible to determine the concentrations of
are subject to revision, and Parties to agreements
sodium, potassium, Calcium and magnesium (and
based on this International Standard are encouraged
other elements such as iron, manganese and alumin-
to investigate the possibility of applying the most re-
ium) in the 0,l ml/l barium chloride extract of the soil.
cent editions of the Standards indicated below.
Members of IEC and ISO maintain registers of cur- If the barium chloride extract has a yellowish-brown
rently valid International Standards. colour, this indicates that some organic matter has
1) To be published.
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SIST EN ISO 11260:2011
ISO 11260:1994(E) 0 ISO
been dissolved. If this occurs, record it in the test re- ISO 11464, to a tightly stoppered polyethylene
Port. centrifuge tube of about 50 ml capacity. Note the
combined mass of tube and soil (m,). Add 30 ml of
NOTES
barium chloride Solution (4.1 .l .l) to the soil and Shake
for 1 h. Balance the tubes and centrifuge at 3 000 g
3 Since organic matter contributes to the CEC, its pres-
for 10 min.
ence will result in a measured CEC value which is an
underestimation of the actual CEC.
Transfer the supernatant liquid to a 100 ml volumetric
flask. Repeat the addition of 30 ml of the barium
4 Inductively coupled Plasma atomic emission spectro-
metry (ICP-AES) may be used as an alternative method for chloride Solution, the shaking and centrifugation twice
the measurement of sodium, potassium, Calcium and
more, adding the supernatant liquid to the 100 ml
magnesium.
volumetric flask each time. Make up to the volume
of the volumetric flask with barium chloride Solution
5 The sum of exchangeable cations may give a result that
(4.1.1 .l).
is greater than the actual CEC due to the dissolution of salts
present in the soil. However, preliminary washing sf the soil
Mix, filter and store the extract for the determination
with water to remove these salts should not be employed
of the concentration of sodium, potassium, Calcium
because it will Change the relative proportions of cations in
and magnesium in accordance with 4.3 and 4.4. Add
the CEC.
30 ml of barium chloride Solution (4.1.1.2) to the soil
cake and Shake overnight. (The barium concentration
4 Procedures
in the equilibrium Solution will be about 0,Oi mol/1
when 2,5 ml of Solution is left in the soil cake.) Bal-
4.1 Leaching
ance the tubes and centrifuge at about 3 000 g for
10 min. Decant the supernatant liquid.
4.1.1 Reagents
Weigh the tube with its contents and cover (%). Add
Use only reagents of recognized analytical grade and 30 ml of magnesium sulfate Solution (4.1 .1.3) to the
water complying with grade 2 of ISO 3696. soil cake and Shake overnight. Balance the tubes and
centrifuge at 3 000 g for IO min. Decant the
supernatant Solution through a coarse filter Paper
4.1.1 .l Barium chloride solution,
c(BaCI,) = 0,l mol/l. (7 cm diameter-) into a conical flask and store for the
determination of the concentration of excess of
Dissolve 24,43 g of barium chloride dihydrate
magnesium in accordance with 4.2.4.
n water and make up to 1 000 ml with
(BaCl,.2H,O) i
described
water at 20 “C. Prepare a blank by following the above
procedure completely without the addition of soil.
4.1 .1.2 Barium chloride solution,
c(BaCI,) = 0,002 5 mol/l.
4.2 Determination of CEC
Dilute 25 ml of the 0,l ml/l barium chloride Solution
to 1 000 ml at 20 “C.
4.2.1 Principle
4.1 .1.3 Magnesium sulfate Solution,
c(MgS0,) = 0,020 0 mol/l.
To prevent the formation of refractory compounds of
magnesium with Phosphate, aluminium, etc. in the
Dissolve 4,93 g + 0,Ol g of magnesium sulfate
flame, an acidified lanthanum Solution is added to the
heptahydrate (MgSO,.7H,O) (see note 6) in water and
solution obtained in accordance with 4.1.2, and
make up to 1 000 ml at 20 “C.
magnesium is then determined by FAAS.
NOTE 6 MgS0,.7H,O may lose water of crystallization
on standing. The reagent should be standardized by titration
with EDTA at pH 10 using Eriochrome Black T indicator or
4.2.2 Reagents
be kept in a bottle in a sealed polyethylene bag placed in a
refrigerator.
Use only reagents of recognized analytical grade and
distilled or deionized water for all solutions.
4.1.2 Leaching procedure
Transfer 2,50 g of air-dried soil (particle size 4.2.2.1 Hydrochlorit acid, c (HCI) = 12 mol/
< 2 mm), for example, pretreated according to (p = 1,19 g/ml).
2
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SIST EN ISO 11260:2011
0 ISO
ISO 11260:1994(E)
4.2.2.2 Magnesium Standard Solution, 1s the magnesium concentration in the
Cl
c(Mg) = 0,001 0 mol/l. Sample, in millimoles per litre;
Pipette 50,O ml of the 0,020 0 mol/1 magnesium sul- is the mass of the centrifuge tube with
ml
fate Solution (4.1 .1.3) into a volumetric flask of air-dried soil, in grams;
1 000 ml and make up to the mark with water.
is the mass of the centrifuge tube with
Q
wet soil, in grams.
4.2.2.3 Acidified lanthanum Solution,
= 10 mg/l.
dLa)
Calculate the cation exchange capacity (@EC) of the
soil using the formula:
Dissolve 15,6 mg of lanthanum nitrate hexahydrate
[La(NO,),.GH,O] in water in a 500 ml volumetric flask,
CEC = (cb, - C2)3 ooo/m
add 42 ml of hydrochloric acid (4.2.2.1) and make up
to the mark with water.
CEC is the cation exchange capacity of the soil,
4.2.3 Calibration series
in centimoles positive Charge per kilogram;
Pipette 0 ml, 1 ml, 2 ml, 3 ml, 4 ml and 5 ml of
is the corrected magnesium concentration
C2
magnesium Standard Solution (4.2.2.2) into a series
in the Sample, in millimoles per litre;
of 100 ml volumetric flasks. Add ‘l0 ml of acidified
lanthanum Solution (4.2.2.3), make each flask up to
is the magnesium concentration in the
cbl
the mark with water and mix. These calibration sol-
blank, in millimoles per litre;
utions have magnesium concentrations of 0 mmol/l,
m is the mass of the air-dried Sample, in
0,Ol mmol/l, 0,02 mmol/l, 0,03 mmol/l, 0,04 mmol/l
grams.
and 0,05 mmol/l, respectively.
If the CEC exceeds 40 cmol+/kg, repeat the determi-
4.2.4 Spectrometric procedure
nation using less soil, adjusting the calculation ac-
cordingly.
Pipette 0,200 ml of each of the final filtrates of the
soil samples (sec 4.1.2) and of the blanks (see 4.1.2)
NOTE 7 The unit “centimoles positive Charge per a kilo-
into individual 100 ml volumetric flasks. Add 0,3 ml
gram”, written in abbreviated form as cmol+/kg, is an ab-
of the barium chloride Solution (4.1 .l .l) to the filtrates
solute amount equivalent to the formerly used unit
of the soil samples and the blanks. Next, add IO ml
millielectrons per hundred grams.
of acidified lanthanum Solution (4.2.2.3) to each flask,
make up to the mark with water and mix.
4.3 Determination of exchangeable sodium
Determine the magnesium concentration in the di-
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Bodenbeschaffenheit - Bestimmung der effektiven Kationenaustauschkapazität und der Basensättigung unter Verwendung von Bariumchloridlösung (ISO 11260:1994)Qualité du sol - Détermination de la capacité d'échange cationique effective et du taux de saturation en bases échangeables à l'aide d'une solution de chlorure de baryum (ISO 11260:1994)Soil quality - Determination of effective cation exchange capacity and base saturation level using barium chloride solution (ISO 11260:1994)13.080.10Chemical characteristics of soilsICS:Ta slovenski standard je istoveten z:FprEN ISO 11260kSIST FprEN ISO 11260:2011en,fr,de01-april-2011kSIST FprEN ISO 11260:2011SLOVENSKI
STANDARD
kSIST FprEN ISO 11260:2011
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
FINAL DRAFT
FprEN ISO 11260
December 2010 ICS 13.080.10 English Version
Soil quality - Determination of effective cation exchange capacity and base saturation level using barium chloride solution (ISO 11260:1994)
Qualité du sol - Détermination de la capacité d'échange cationique effective et du taux de saturation en bases échangeables à l'aide d'une solution de chlorure de baryum (ISO 11260:1994)
Bodenbeschaffenheit - Bestimmung der effektiven Kationenaustauschkapazität und der Basensättigung unter Verwendung von Bariumchloridlösung (ISO 11260:1994) This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee CEN/TC 345.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. FprEN ISO 11260:2010: EkSIST FprEN ISO 11260:2011
FprEN ISO 11260:2010 (E) 2 Contents Page Foreword .3 kSIST FprEN ISO 11260:2011
FprEN ISO 11260:2010 (E) 3 Foreword The text of ISO 11260:1994 has been prepared by Technical Committee ISO/TC 190 “Soil quality” of the International Organization for Standardization (ISO) and has been taken over as FprEN ISO 11260:2010 by Technical Committee CEN/TC 345 “Characterization of soils”, the secretariat of which is held by NEN. This document is currently submitted to the Unique Acceptance Procedure. Endorsement notice The text of ISO 11260:1994 has been approved by CEN as an FprEN ISO 11260:2010 without any modification.
kSIST FprEN ISO 11260:2011
kSIST FprEN ISO 11260:2011
INTERNATIONAL STANDARD ISO 11260 First edition 1994-08-15 Soil quality - Determination of effective cation exchange capacity and base Saturation level using barium chloride solution Qual26 du sol - Dgtermination de Ia capacite d’khange ca tionique effective et du taux de Saturation en bases khangeables a I’aide d’une Solution de chlorure de baryum Reference number ISO 11260:1994(E) kSIST FprEN ISO 11260:2011
ISO 11260:1994(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Esch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 11260 was prepared by Technical Committee ISODC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics. Annexes A and B of this International Standard are for information only. 0 ISO 1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permission in writing from the publisher. International Organization for Standardization Case Postale 56 l CH-l 211 Geneve 20 l Switzerland Printed in Switzerland ii kSIST FprEN ISO 11260:2011
INTERNATIONAL §TANDARD 0 ISO ISO 11260:1994(E) Soil quality - Determination of effective cation exchange capacity and base Saturation level using barium chloride Solution 1 Scope This International Standard specifies a method for the determination of the cation exchange capacity (CEC) at the pH of the soil and of the determination of the content of exchangeable sodium, potassium, Calcium and magnesium in soil. This International Standard is applicable to all types of air-dried soil samples; pretreatment according to ISO 11464 is recommended. NOTES 1 The method described suffers from interference from Calcium as calcite or gypsum in the Sample. Also, the pres- ence of any soluble salts gives values for the exchangeable cations that are higher than the actual exchangeable amounts 131, 141. 2 Measurement of the specific electrical conductivity of the soil samples according to ISO 11265 will indicate if the soil samples are affected by salt. 2 Normative references The following Standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent editions of the Standards indicated below. Members of IEC and ISO maintain registers of cur- rently valid International Standards. ISO 3696: 1987, Water for analytical laboratory use - Specifica tion and tes t me thods. ISO 11265: 2) Soil quality - specific electriial conductivity. Determination of the ISO 11464: 2) Soil quality - Pretrea tment of sam- ples for physik-chemical analyses. 3 Principle The determination of CEC as specified in this Inter- national Standard is a modification of the method proposed by Gillman [SI. The CEC of soil samples is determined at the pH of the soil and at a low total ionic strength (about 0,Ol mol/l). The soil is first saturated with respect to barium by treating the soil three times with a 0,l mol/1 barium chloride Solution. Thereafter, the soil is equilibrated with a 0,Ol mol/1 barium chloride Solution. Subse- quently, a known excess of 0,02 mol/1 magnesium sulfate is added. All the barium present, in Solution as well as adsorbed, is precipitated in the form of highly insoluble barium sulfate and, consequently, the sites with exchangeable Ions are readily occupied by magnesium. The excess magnesium is determined by flame atomic absorption spectrometry (FAAS). lt is also possible to determine the concentrations of sodium, potassium, Calcium and magnesium (and other elements such as iron, manganese and alumin- ium) in the 0,l ml/l barium chloride extract of the soil. If the barium chloride extract has a yellowish-brown colour, this indicates that some organic matter has 1) To be published. kSIST FprEN ISO 11260:2011
ISO 11260:1994(E) 0 ISO been Port. dissolved. If this occurs, record it in the test re- NOTES 3 Since organic matter contributes to the CEC, its pres- ence will result in a measured CEC value which is an underestimation of the actual CEC. 4 Inductively coupled Plasma atomic emission spectro- metry (ICP-AES) may be used as an alternative method for the measurement of sodium, potassium, Calcium and magnesium. 5 The sum of exchangeable cations may give a result that is greater than the actual CEC due to the dissolution of salts present in the soil. However, preliminary washing sf the soil with water to remove these salts should not be employed because it will Change the relative proportions of cations in the CEC. 4 Procedures 4.1 Leaching 4.1.1 Reagents Use only reagents of recognized analytical grade and water complying with grade 2 of ISO 3696. 4.1.1 .l Barium chloride solution, c(BaCI,) = 0,l mol/l. Dissolve 24,43 g of barium chloride dihydrate (BaCl,.2H,O) i n water and make up to 1 000 ml with water at 20 “C. 4.1 .1.2 Barium chloride solution, c(BaCI,) = 0,002 5 mol/l. Dilute 25 ml of the 0,l ml/l barium chloride Solution to 1 000 ml at 20 “C. 4.1 .1.3 Magnesium sulfate Solution, c(MgS0,) = 0,020 0 mol/l. Dissolve 4,93 g + 0,Ol g of magnesium sulfate heptahydrate (MgSO,.7H,O) (see note 6) in water and make up to 1 000 ml at 20 “C. NOTE 6 MgS0,.7H,O may lose water of crystallization on standing. The reagent should be standardized by titration with EDTA at pH 10 using Eriochrome Black T indicator or be kept in a bottle in a sealed polyethylene bag placed in a refrigerator. ISO 11464, to a tightly stoppered polyethylene centrifuge tube of about 50 ml capacity. Note the combined mass of tube and soil (m,). Add 30 ml of barium chloride Solution (4.1 .l .l) to the soil and Shake for 1 h. Balance the tubes and centrifuge at 3 000 g for 10 min. Transfer the supernatant liquid to a 100 ml volumetric flask. Repeat the addition of 30 ml of the barium chloride Solution, the shaking and centrifugation twice more, adding the supernatant liquid to the 100 ml volumetric flask each time. Make up to the volume of the volumetric flask with barium chloride Solution (4.1.1 .l). Mix, filter and store the extract for the determination of the concentration of sodium, potassium, Calcium and magnesium in accordance with 4.3 and 4.4. Add 30 ml of barium chloride Solution (4.1.1.2) to the soil cake and Shake overnight. (The barium concentration in the equilibrium Solution will be about 0,Oi mol/1 when 2,5 ml of Solution is left in the soil cake.) Bal- ance the tubes and centrifuge at about 3 000 g for 10 min. Decant the supernatant liquid. Weigh the tube with its contents and cover (%). Add 30 ml of magnesium sulfate Solution (4.1 .1.3) to the soil cake and Shake overnight. Balance the tubes and centrifuge at 3 000 g for IO min. Decant the supernatant Solution through a coarse filter Paper (7 cm diameter-) into a conical flask and store for the determination of the concentration of excess of magnesium in accordance with 4.2.4. Prepare a blank by following the above described procedure completely without the addition of soil. 4.2 Determination of CEC 4.2.1 Principle To prevent the formation of refractory compounds of magnesium with Phosphate, aluminium, etc. in the flame, an acidified lanthanum Solution is added to the solution obtained in accordance with 4.1.2, and magnesium is then determined by FAAS. 4.2.2 Reagents Use only reagents of recognized analytical grade and distilled or deionized water for all solutions. 4.1.2 Leaching procedure Transfer 2,50 g of air-dried soil (particle size < 2 mm), for example, pretreated according to 4.2.2.1 Hydrochlorit acid, c (p = 1,19 g/ml). (HCI) = 12 mol/ 2 kSIST FprEN ISO 11260:2011
0 ISO ISO 11260:1994(E) 4.2.2.2 Magnesium Standard Solution, c(Mg) = 0,001 0 mol/l. Pipette 50,O ml of the 0,020 0 mol/1 magnesium sul- fate Solution (4.1 .1.3) into a volumetric flask of 1 000 ml and make up to the mark with water. 4.2.2.3 Acidified lanthanum Solution, dLa) = 10 mg/l. Dissolve 15,6 mg of lanthanum nitrate hexahydrate [La(NO,),.GH,O] in water in a 500 ml volumetric flask, add 42 ml of hydrochloric acid (4.2.2.1) and make up to the mark with water. 4.2.3 Calibration series Pipette 0 ml, 1 ml, 2 ml, 3 ml, 4 ml and 5 ml of magnesium Standard Solution (4.2.2.2) into a series of 100 ml volumetric flasks. Add ‘l0 ml of acidified lanthanum Solution (4.2.2.3), make each flask up to the mark with water and mix. These calibration sol- utions have magnesium concentrations of 0 mmol/l, 0,Ol mmol/l, 0,02 mmol/l, 0,03 mmol/l, 0,04 mmol/l and 0,05 mmol/l, respectively. 4.2.4 Spectrometric procedure Pipette 0,200 ml of each of the final filtrates of the soil samples (sec 4.1.2) and of the blanks (see 4.1.2) into individual 100 ml volumetric flasks. Add 0,3 ml of the barium chloride Solution (4.1 .l .l) to the filtrates of the soil samples and the blanks. Next, add IO ml of acidified lanthanum Solution (4.2.2.3) to each flask, make up to the mark with water and mix. Determine the magnesium concentration in the di- luted Sample extracts (c,), the diluted blank (cb,) and in the calibration solutions by FAAS at wavelength 285,2 nm, with the instrument set according to the manufacturer’s instructions for Optimum perform- ante. 4.2.5 Calculation
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