RAPID SOIL FERTILITY SURVEY & SOIL TESTING INSTITUTE

ThokarNiazBaig, Lahore Ph: +92 42 99233581 E-mail: director_sfri@yahoo.com

No. 6982-90
Dated 05.04.2021
To

All Divisional Heads/Chemists

Soil Fertility Research Institute,
Thokar Niaz Baig, Lahore

Subject: SFRI-GUIDE FROM SAMPLE RECEIVING TO ISSUANCE OF TEST

RESULTS (2021)
By the grace of Allah Almighty, who has enabled us to write the booklet “SFRI-
GUIDE FROM SAMPLE RECEIVING TO ISSUANCE OF TEST RESULTS (2021)” which
almost covers all aspects of analyzing fertilizer samples in order to cover up all the shortcomings
that exist in the process of dealing with litigation samples drawn during the anti-adulteration
campaign. It contains all of the standard test methods that will be used uniformly in all fertilizer
research laboratories, as well as the following.

1. Guidelines for handling of FCO fertilizer samples

2. TORs: Sample receiving
3. TORs: Sample coding
4. TORs: Sample storage
5. TORs: Sample movement within lab.
6. TORs: Sample analysis
7. TORs: Issuance of test results
8. TORs: Fertilizer samples disposal

You are required to follow all instructions and use standard test methods in order
to achieve consistent results with less variation. In this regard, please print and distribute this
copy to all of your analysts for strict enforcement in order to improve the precision of handling
of fertilizer samples obtained as part of an anti-adulteration campaign for accuracy, repeatability,
and reliability, which is our prime objective.

(DR MUHAMMAD AKRAM QAZI)

Chief Scientist/ Director
Soil Fertility Research Institute, Punjab,
Lahore
No. 6991-7018 Dated: 05.04.2021

Copy forwarded to all heads of district Soil & Water Testing Labs in Punjab.

(DR MUHAMMAD AKRAM QAZI)

Chief Scientist/ Director
Soil Fertility Research Institute, Punjab,
Lahore
CC.

1. Ps to Additional Secretary (Admin), Agriculture Department, Punjab, Lahore.

2. Chief Scientist/Director General Agriculture (Research), AARI, Faisalabad
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

2021
SFRI-GUIDE FROM SAMPLE RECEIVING TO ISSUANCE OF TEST RESULTS
Compiled and edited by Dr. Muhammad Akram Qazi
Director, Soil Fertility Research Institute, Punjab, Lahore

with the assistance of the editors

Muhammad Salik Ali Khan
and
Dr. Faraz Ahmed
Funded by the Soil Fertility Research Institute, Punjab, Lahore
___________________________________________________________
Recommended Citation
M. A. Qazi, M. S. A. Khan, F. Ahmed (2021), SFRI-Guide from sample receiving to issuance of
test results. Directorate of Soil Fertility Research Institute, Department of Agriculture, Punjab,
Lahore
Important Disclaimer
A reasonable care was taken to make the information in this SFRI-Guide accurate and up-to-date
and in accordance with the ISO/IEC 17025:2017 international standard and Standard Operating
Procedures (SOP) issued by the Directorate, Soil Fertility Research Institute, Punjab, Lahore from
time to time. However, authors would appreciate any comments and suggestions for further
improvement of this SFRI-Guide.
Authors accept no liability whatsoever, by reason of negligence or otherwise, arising from any
use or release of information in, or referred to in, this guide, or any error, inaccuracy, or omission
in the information.
The analysis methods described in this guide need verification to ensure that the laboratory is
capable of meeting the test method performance specifications. Verification of a test method
demonstrates that the laboratory has met the test method’s performance specifications and must
be completed before the method is used for routine testing.

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ FOREWORD

During visit to Soil and Water Testing Laboratories across the Province Punjab, it was observed
that different work strategies and methods for analysis of fertilizer samples were adopted in
laboratories working under administrative control of Soil Fertility Research Institute, Punjab,
Lahore. It is noteworthy that different analysis methods produce different results and hence
separate interpretation is required. A need was identified to develop a guide to harmonize the
work strategy and analysis methods among the laboratories.
This SFRI-Guide should be followed in all soil and water testing laboratories across province
Punjab and will help to reduce the reporting of contradictory analytical results between the
laboratories.
I hope you will find this SFRI-Guide useful and welcome any comments that may help for
improvement.

Director
Soil Fertility Research Institute (SFRI), Punjab, Lahore

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ ACKNOWLEDGEMENT
Dr. Asad Rehman Gillani, Secretary Agriculture, Punjab deserves special acknowledgement for
his inspiration and commitment in enabling us to produce a document harmonizing the analysis
work performed in all SWT Laboratories of Agriculture Department.

FUTURE WORK STRATEGY OF SFRI

1. To improve the efficiency of service delivery of all divisional and district labs.
2. In all labs, all laboratory tests will be performed in accordance with uniform standard test
methods.
3. To improve the handling of fertilizer samples collected as part of an anti-adulteration
campaign for accuracy, repeatability, and reliability.
4. By implementing reforms in the field wing, the institute's original mandate of formulating
fertilizer recommendations will be made more efficient and authenticated. In Sha Allah

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ CONTENTS
Foreword ii
Acknowledgements iii
Future work strategy of SFRI iii
1. Introduction 1
2. Guidelines for handling of FCO fertilizer samples 2
3. Estimation of ureic, ammoniacal and nitric nitrogen in fertilizer by Kjeldahl 8
method
4. Estimation of phosphorus in phosphatic fertilizer by titrimetric method 11
5. Estimation of total phosphorus from bio-organic fertilizers 14
6. Estimation of potassium in potash fertilizer by flame photometer method 16
7. Estimation of water-soluble zinc in fertilizer by flame atomic absorption 17
spectrophotometer
8. Estimation of acid-soluble zinc copper iron and manganese in inorganic 19
materials and mixed fertilizers by atomic absorption spectrophotometer
9. Estimation of water-soluble fraction of micronutrients (zinc, copper, iron, 21
and manganese) by flame atomic absorption spectrophotometer
10. Estimation of charred/ashed fraction of multi-micros (zinc, copper, iron, and 22
manganese) by flame atomic absorption spectrophotometer
11. Estimation of chelated zinc in chelated zinc fertilizer by flame atomic 23
absorption spectrophotometer
12. Estimation of chelated iron in chelated fertilizer by flame atomic absorption 25
spectrophotometer
13. Estimation of chelated copper and manganese in chelated fertilizer by flame 26
atomic absorption spectrophotometer
14. Estimation of acid-soluble fraction of calcium and magnesium by flame 27
atomic absorption spectrophotometer
15. Estimation of water-soluble boron content in fertilizer 28
16. Gravimetric method for the determination of humic acid content in solid and 30
liquid fertilizers
17. Estimation of organic matter content in compost 31
18. Determination of cation exchange capacity of organic matter/ composts 32
19. Estimation of Sulphur in SOP fertilizer sample 33
20. Estimation of chlorides in sulphate of potash fertilizer sample 35
21. Estimation of paclobutrazol in plant growth regulator samples using high 36
performance liquid chromatography
22. Estimation of naphthyl acetic acid (NAA) in plant growth regulator samples 38
using high performance liquid chromatography
23. Estimation of Mepiquat chloride in plant growth regulator samples using 39
high performance liquid chromatography.

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

24. Estimation of gibberellic acid in plant growth regulator samples using high 40
performance liquid chromatography

List of appendices
1. Appendix-1: Analysis Fee Receipt (Template) 42
2. Appendix-2: Analysis Request Form (Template) 43
3. Appendix-3: Order sheet for fertilizer analysis/Samples delivery sheet 44
4. Appendix-4: Fertilizer Analysis Report (Template) 45

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Introduction
The Soil Fertility Research Institute, Lahore oversees 37 soil and water testing laboratories, one in
each of Punjab's districts. Nine (9) laboratories are part of the provincial system including
Provincial Reference Fertilizer Testing Laboratory, Raiwind, while 28 are part of the district
system. These laboratories provide advice or services to farmers and other stakeholders, such as
the fertilizer industry, on the quality of soil, water, plants, fertilizers, amendments, etc. as well as
how to make the best use of their soil and water resources.

Nine state-of-the-art laboratories functioning under provincial jurisdiction are ISO-17025:2017

accredited. These laboratories have the capability of analyzing soil, water, plant, and fertilizer
samples with high-tech instruments such as ICP-OES, HPLC, GC, AAS, and FTIR. These
laboratories also provide analytical services to the research institutes in addition to their
routine activities. More significantly, these laboratories are monitoring the quality of fertilizers
sold in Punjab as part of the province's anti-adulteration drive, which is governed by the Fertilizer
Control Order 1973.

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Guidelines for handling of FCO fertilizer samples

All the divisional (Primary) Soil and Water Testing Laboratories across Punjab should strictly
adhere to the ISO-17025:2017 standard clause 4 which emphasizes the implementation of
“Impartiality” and “Confidentiality” in all regulatory laboratories. The following instructions, in
addition to the ISO standard requirements, are advised to be followed in this regard:

The principal scientist shall notify a committee with a detailed description of their TORs on the
subject of receiving, handling, storage, coding, decoding, and reporting results of FCO fertilizer
samples. For the sake of strict safety and security, two officers will be nominated as custodians of
all forms of samples, especially in court cases and result discrepancy cases. Moreover, any
member of this committee will not be given the task of analyzing FCO samples for the sake of
confidentiality and impartiality.

■ TORs : Sample receiving

1. At the time of receiving of the fertilizer samples, the committee will check the following
information.
a. Cross match the name and CNIC # of the special messenger with his original CNIC as
authorized samples carrier mentioned in forwarding letter of the Controller (Assistant /
deputy Director, Agriculture (Extension).
b. The sample seal must be intact, readable, reliable, and match with the imprint on the outer
covering of the cloth bag and Form-1.
c. Check Form-1, label, and outer covering of the fertilizer samples for following needful
requirements.
i. Form-1 shall have standard format.
ii. Ensure that there are at least 10 working days left in the registration's expiry date,
counted from the next day of bringing the sample into the lab.

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

iii. All boxes on this form must be filled with relevant information, and the entries must be
compared to those on the sample label, the outer covering of the cloth bag, and the
forwarding letter.
iv. Compare the name, address, and signature of the dealer on Form-1 with the name,
address, and signature on the outer covering cloth bag.
v. Crossmatch the brand name, manufacturer, registration, and batch listed on form-1 with
the outer covering cloth bag and fertilizer sample label.
vi. Ingredients with symbolic formulas such as K2O, P2O5, and concentrations in
percentages are written on this Form-1, which must crossmatch with the fertilizer
sample label.
vii. Check the signatures of the Controller, Dealer, and Witnesses, and compare them to the
signatures on the outer covering of cloth bag.
2. The receipt for receiving the samples will be given to the special messenger for his records.

■ TORs: Sample coding

1. The following details of fertilizer samples shall be entered in the Data Record Register by the
sample opening committee.
a. Serial number
b. Date of opening the sample.
c. Registration number/Code
d. The controller and his letter No. and date.
e. Manufacturer of fertilizer and his address
f. Dealer and his address
g. Trade name of fertilizer
h. Ingredients to be measured in terms of concentration. The nutrients in liquid fertilizer
samples, in particular, are only measured in terms of weight / volume (W/V %). The
controller will need to correct a liquid sample that is labeled as W/W %.
i. Detailed description of the physical conditions of the samples (shape, size, colour, moisture
or dryness of sample and texture).

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

j. Assign a special code for the order of analysis and should never be disclosed to anyone.
k. Analyst, who is engaged in fertilizer analysis, should not be included, neither in this
committee nor in fertilizer receiving, storing, coding, decoding, and issuing results of these
samples.
l. Each member of the committee shall have equal rights.
m. After completing the receiving formalities, the receiving committee must sign off on each
sample entered in the data record register.

■ TORs: Sample storage

1. The fertilizer samples must be kept in chronological order in a safe place that is double locked
with keys. Liquid fertilizer samples should be placed on the lower shelves of the cabinet to
prevent contamination of other samples in the case of a leak or spill.
2. All previously taken over and fresh samples should be placed in the control sample room for
the placement of samples in secure custody. The room should have two different locks meant
for a separate member of the committee. The door of the sample control room shall not be
opened by any single member, both of which will operate the sample room door jointly with
the permission of chief scientist.
3. No duplicate key shall be allowed to any other staff member and not even chief scientist or
Principal Scientist shall be allowed to open this lock of door and the record of opening the
sample control room door shall be well documented.
4. Committee shall maintain the database of each sample placed in the sample room.
5. Each member of the committee shall have equal rights.
6. Strict adherence to the above TORs shall be observed.

■ TORs: Sample movement within lab.

1. The committee shall transfer a little part of each received sample in a separate washed,
cleaned, and dry container after marking respective code on it. Along-with this container, the
committee will prepare samples analysis order sheet containing only the following
information.

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

a. A secret code
b. Detailed description of the physical conditions of the samples (shape, size, color, and
texture).
c. Name of the parameter to be tested, without disclosing the company claim or any other
identity.
d. Separate analysis order sheet must also be given to each analyst.

■ TORs: Sample analysis

1. The fertilizer sample, along with an "Analysis order sheet/Flow sheet" (see Appendix-3)
and a transcript of the sample's physical conditions as noted by the sample opening
committee, should be sent to the relevant analyst.
2. The analysis order sheet should be filled out in such a way that it aids in the construction
of a timeline of events that begins with the receipt of the sample and ends with the
delivery of the test results.
3. The analyst will receive the samples after cross-checking the physical conditions written
on the analysis order sheet with those of the actual samples in the containers.
4. The analyst will follow the standard test methods (STM) mentioned in this SFRI-Guide,
however, all laboratories must verify that they can perform the methods (STM) and
achieve desired results. As part of the ISO 17025:2017 standard, a record of the
verification must be kept. Verification must be validated if the STM is amended by the
issuing authority.
5. The STMs / flow chart must be displayed near the test site, preferably at the sample
analysis workplace.
6. All regulatory fertilizer samples should be analyzed in three replicates, and if necessary, a
second analyst should be engaged to confirm the results.
7. To ensure the validity of test results, the analyst must use reference materials/reference
standards or quality control materials in addition to the fertilizer sample. Each batch of
analysis should include these reference standards as a sample. As a reference standards,

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

you can use samples received from the Proficiency Testing Program or samples from the
Inter laboratory Comparison Program, or analytical grade salts of the element under test.
8. The recovery of these reference standards should not be less than 95%. Use correction
factor in case test results of reference standards differ from its true value up to the extent
of 5%. If deviation is more than 5%, repeat the analysis.
9. The analyst should keep track of all sources of verification that can be used to confirm the
recorded results. All such records are classified as technical records under the ISO
17025:2017 standard (Clause 7.5) and should be maintained in perfect shape. This record
may include:
a. Logbooks of the instruments
b. Readouts from instruments and titrations readings
c. All sort of calculations
d. Test repeatability
e. Graphs or its equation with fitness of the curve
f. Crossmatch sample results to those of a reference sample on a regular basis to
ensure their authenticity.
10. Do not use lead pencil while recording the sources of verifications.
11. When an analyst seeks supervisory assistance from one of his or her senior officers, he or
she should document it in his or her lab notebook. To avoid lost papers or sheets, lab
notebooks should be in bind format.
12. Every page of the lab notebooks should be a control document, page numbering and
certification on first page by the Lab Supervisor.
13. Analysts must sign and document the results reporting date at the end of their shift on that
working day.
14. The analysts will submit the results with his / her signature on analysis order sheet to the
supervisor.
15. The analysts will submit the analysis result within ten working days whereas, intelligence-
based raided samples within two working days.

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ TORs: Issuance of test results

1. The Assistant Agricultural Chemist shall check the analysis results and verify the sources
of verification. (See Appendix-3) and after satisfaction, he / she shall put signature on
sources of verification and analysis order sheet and will send the analysis order sheet/flow
sheet to the Agricultural Chemist.
2. The Assistant Agricultural Chemist should ensure that all lab activities related to fertilizer
samples are tracked in a continuous chain from sample receiving to lab results issuance.
3. It is important to obtain a second analyst's opinion before reporting the results for
confirmation.
4. The Agricultural Chemist will review analysis work that has been reported by the analyst
on a random basis.
5. The Agricultural Chemist will approve the results and allow for issuance of results.
6. After approval, Assistant Agricultural Chemist will finalize the report on prescribed
format and issue the report after getting signatures.

■ Fertilizer samples disposal committee

Agricultural Chemist will notify the fertilizer disposal committee after getting approval from
Additional Secretary (Task Force),

 This committee should comprise of three officers including one convener and will be
responsible for disposal of 1st portion of fertilizer samples.
 A list will be prepared for the following categories.
o Fit samples
o Unfit samples
o Court/appeal cases
o Unfit samples from reference lab after retesting of 30% fit-declared samples.
 Except fit samples, all samples will be retained till the finality of the decision.
 List will be prepared as following format.

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

Sr. No. Product Name Lab. Code Composition

 Disposal committee will get the final approval from Agricultural Chemist for disposal.
 Disposal committee will also be responsible for handing-over the stock of samples to the
respective/nearest research institute/station.
 All the record of handing over and receiving will be maintained properly.

■ Fertilizer Testing
ESTIMATION OF UREIC, AMMONIACAL AND NITRIC NITROGEN IN FERTILIZER
BY KJELDAHL METHOD
■ Principle
The NH3 in fertilizer sample or digested fertilizer sample is distilled in alkaline medium and
absorbed in standard acid. Absorbing solution is an aqueous boric acid [B(OH)3] solution of 2-
4% concentration. The ammonia is quantitatively captured by the boric acid solution forming
solvated ammonium ions. When using the boric acid solution as absorbing solution, titration is
performed using standard solutions of sulfuric acid (concentrations in the range of 0.01N to 0.5N)
and the amount of ammonia (as N) is calculated from the volume of standard acid consumed.
■ Total N
Total Nitrogen includes all forms of inorganic-N like NH4-N, NO3-N, Urea-N, and also
compounds like protein, amino acids, and other derivatives. Depending upon the form of N
present in particular sample, specific methods are adopted to get the Total Nitrogen.
■ Ureic N
Organic nitrogenous materials when digested with H2SO4 are oxidized to CO2 and H2O and their
inorganic N is released. During digestion part of H2SO4 is reduced to SO2 which in turn reduces
nitrogenous materials to ammonia (NH3). Ammonia combines with H2SO4 and form (NH4)2SO4 at
the end of digestion.
■ Nitrate-N

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

The procedure for the determination of nitrate and ammoniacal nitrogen with reduction is done
by using Devarda’s alloy. When a solution of nitrate ions and Devarda’s alloy is mixed with
aqueous sodium hydroxide, the mixture gently liberates ammonia gas. This conversion under the
form of ammonia, requires some minutes. The method is applicable to all nitrogenous fertilizers,
including compound fertilizers, in which nitrogen is found exclusively in nitrate form or in
ammoniacal-N and nitrate form.
■ Equipment
 Kjeldhal’s distillation apparatus
 Digestion block
 Digestion tubes
 Conical flasks, 500ml
 Pipette,1ml, 5ml, 10 ml (Bulb type)
 Cylinder, 50ml
 Beaker glass 500ml, 1000ml
 Wash bottle
 Burette
■ Reagents
 H2SO4 (0.1N): Prepare standard 0.1N solution (dissolve 2.8ml of H2SO4 when the specific
gravity is 1.84 and purity is 95.0% and make volume one liter) and standardize against 0.1N
NaOH.
 NaOH (0.1N): (Prepare 0.1 N NaOH by dissolving 4.0 g NaOH in distilled water and make
volume 1 liter and standardize it against 0.1 N potassium hydrogen phthalate (dissolve 20.423g
of potassium hydrogen phthalate and make volume one liter).
 Sodium hydroxide (NaOH) 40% solution: Dissolve 400 g solid NaOH in distilled water and
dilute to one liter.
 Boric acid 4%solution: Dissolves 40g boric acid in distilled water and dilute to one liter.
 Bromocresol green indicator: Weigh 0.5g bromocresol green and 0.1g methyl red indicator
and make volume 100ml with 95% ethyl alcohol.
 Devarda’s alloy: (50% Cu, 45% Al, 5% Zn)
 Digestion Mixture: (9:1, K2SO4: CuSO4)

■ Procedure
1. Ureic nitrogen
Weigh accurately 0.5g, ground and homogenized sample and transfer to the digestion tube, take
1ml of filtered sample in case of liquid. Add 1.0g of digestion mixture Add 10-12 ml of
concentrated sulfuric acid to the digestion tube. Place the tube in the digestion block. Continue

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

heating for at least 2 hours at 400 oC until the contents of tube changes from black to light green
or straw yellow or water white. Remove the digestion tube from digestion block and cool. Now
sample is ready for distillation apparatus.
Place tube on distillation unit add 50ml of 40% NaOH and 10ml of distilled water in digestion
tube and start distillation process. Place 250ml conical flask on receiver containing 40ml of 4%
boric acid and few drops of bromocresol green indicator in such a way that outlet of receiver
properly dipped in the boric acid. Nitrogen will be collected in the receiver containing 4% boric
acid. Titrate against 0.1N standardized sulfuric acid from golden yellow to purple end point.

2. Ammoniacal-N and nitrate-N

Weigh accurately 0.5 g ground and homogenized fertilizer sample in the digestion tube. Place the
tube on distillation apparatus. If NO3-Nitrogen and NH4-Nitrogen are to be determined, add 3.0 g
Devarda’s alloy along with the fertilizer sample but if only NH4-Nitrogen is to be determined then
just take 0.5 g of sample in the digestion tube and distillate (without Devarda’s alloy). Distillate
on distillation unit. Nitrogen will be collected in the receiver containing 4% boric acid. Titrate
against 0.1N standardized sulfuric acid from golden yellow to purple end point.
■ Conditions for automatic Kjeldahl distillation unit
 Volume of 40% NaOH: 80 ml
 Volume of 4% Boric Acid: 40 ml
 Volume of distilled water: 10 ml
 Steam Flow: 100 %
 Distillation time: 4 minutes
■ Calculations
1 ml of 1 N H2SO4 = 0.0141g N.
1ml of 0.1 N H2SO4 = 0.00141 g N
If
0.1 N H2SO4 used in back titration = C ml
Then
C ml of 0.1 N H2SO4 contains N = 0.00141 g N x C
Therefore
% N = C x 0.00141 X 100/w (A-B) = C
Whereas
A = ml of 0.1N H2SO4 used for sample titration
B = ml of 0.1 N H2SO4 used for blank

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

W = weight in grams of fertilizer sample used.

■ Reference / Related Documents
 Tandon HLS (Ed.) 2009. Methods of Analysis of Soils, Plants, Waters, Fertilizer and Organic
Manures Fertilizer Development and Consultation Organization, New Delhi. Pp 161-162
 Official Methods of Analysis of AOAC International, 20th Edition, 2016, Method No. 2.4.03
(AOAC Official Method 955.04), Fertilizers Chapter 2 Page 14-15.
 Official Methods of Analysis of AOAC International, 20th Edition, 2016, Method No. 2.4.10
(AOAC Official Method 892.01), Fertilizers Chapter 2 Page 15.
 VELP SCIENTIFICA®. APPLICATION NOTE-F&F-K-004-2018/A1. APPLICATION
NOTEF&F-K-004-2. Nitrate and Ammonia Determination in Fertilizers according to the
Devarda’s Method Reference: UNIENISO 15476:2009

ESTIMATION OF PHOSPHORUS IN PHOSPHATIC FERTILIZER BY TITRIMETRIC

METHOD

■ Principle
The available-P in phosphate containing fertilizer is extracted with weak acid (citric acid
solution). Extracted phosphorous as orthophosphate can be determined as ammonium
phosphomolybdate after precipitation with ammonium molybdate solution. Precipitates are
filtered, washed to acid free and dissolved in standardized 0.1N sodium hydroxide. The excess of
NaOH is titrated against standardized 0.1N Sulphuric acid to determinate amount of P in fertilizer
sample.

■ Equipment
● Weighing balance
● Volumetric flask-100 ml, 500ml, 1000ml
● Beaker-100 ml, 500ml, 100ml
● Bulb type pipette 1ml, 5ml,10ml
● Conical flask-250ml, 500ml
● Water bath
● Wash Bottle
● Filter paper Whatman No.42
● Funnel with stand
● Blue Litmus paper
● Filter paper sheet

■ Reagents
 Concentrated Nitric Acid

Page 11 of 45
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AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

 Citric Acid Solution 2%: Dissolve 20g of citric acid 1-hydrate salt (C6H8O7.H2O,
210.14g/mol, Analytical grade) in distilled water and make volume one liter.
 Ammonium Molybdate Solution, (3%): Dissolve 30-gram Ammonium Molybdate tetra
hydrate ((NH4)6Mo7O24.4H2O, Analytical grade) salt in 1000ml distilled water.
 Ammonium Nitrate Solution, (50 %): Dissolve 500-gram Ammonium Nitrate (NH4NO3,
80.04g/mol, Analytical grade) salt in1000ml distilled water.
 Phenolphthalein indicator: Dissolve 01-gram phenolphthalein indicator in 100ml 50%
ethanol (for 50% ethanol take 50ml ethanol and add 50ml distilled water)
 Standardized 0.1 N Sulphuric Acid: Dissolve 2.8ml of concentrated H2SO4 of AR grade
with specific gravity 1.84 and purity 95.0% and make volume one liter with distilled water
and standardize against 0.1N NaOH.
 NaOH 0.1N: Prepare 0.1 N NaOH by dissolving 4.0 g NaOH in distilled water and make
volume 1 liter and standardize it against 0.1 N potassium hydrogen phthalate.
 Potassium Hydrogen Phthalate Solution, 0.1N: Dissolve 20.423gram Potassium
Hydrogen Phthalate (C8H5KO4, 204.23g/mol Analytical grade) salt in 1000 ml DI water.
■ Procedure
Weigh accurately 0.5 g homogenized phosphatic fertilizer sample previously grinded and sieved
through 40 mesh sieves, in 100 ml volumetric flask, add citric acid solution (2%) approximately
50ml, raise the temperature up to 65oC in water bath and shake for 60 minutes on mechanical
shaker @ 270rpm. After shaking make volume up to mark with citric acid (2%) solution. Filter
and take 10 ml solution from filtrate, in a 250 ml conical flask. Add 5 ml, concentrated nitric acid
and 15 ml, ammonium nitrate solution (50 %). Heat the contents gently in water bath at 65oC and
then add gradually 50 ml of ammonium molybdate solution (3%). Shake the conical flask during
ammonium molybdate solution addition.
Yellow precipitate of ammonium phosphomolybdate will form depending on the concentration of
phosphorus present in the given fertilizer sample. Stay for one night. Next day filter the yellow
precipitates using Whatman No. 42 and wash with ice cold distilled water till the filtrate does not
turn blue litmus to red. This indicates that precipitates are now acid free. Now transfer the acid
free precipitates along with filter paper into the same conical flask. Care should be taken that the
same conical flask should also be acid free. Dissolve the precipitates completely in 0.1 N sodium
hydroxide by adding 10 ml each time until the yellow color disappears. Note the amount of alkali
used. Now add 2-3 drops of phenolphthalein indicator. Pink color will develop. Titrate against 0.1
N Sulphuric acid with continuous shaking till colourless end point. Note the volume of Sulphuric
acid used.

Page 12 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ CALCULATIONS
% P2O5 = 0.000309x X-Y x 100x100
10x0.5
Whereas
X = 0.1N NaOH used to dissolve precipitate
Y = 0.1N H2SO4 used for back titration.
OR
%P2O5 = (x-y) x 0.618
If 0.5gm fertilizer sample is used

■ DETAIL OF CULCULATIONS
During chemical reaction out of 23 molecules of NaOH only one molecule of Na is used to form
Na (NH4) HPO4 which contain one molecule of P.
Therefore, ammonium phosphomolybdate precipitate contains Na and P in the ratio of 1:1.
i .e, normal solution of NaOH (23gm Na/L) =1 N solution of P (31g P / L).
So 31/ 23 =1.3478g P/ L
1 N NaOH =1.3478x2.29g P2O5/ L (for P to P2O5 use 2.29)
-do- =3.0864g P2O5 / liter
-do- =0.003086g P2O5/ml
1 ml of 0.1 N NaOH =0.0003086g P2O5/ml
R ml of 0.1 N NaOH =0.0003086x R g P2O5 /ml (R = reading)
10ml of 0.1 sample contains = 0.000386 x R If 10 ml aliquot is used.
1 ml of sample contains =0.0003086 x R/10
100ml of sample contains=0.0003086 x R x 100/10
0.5 gm fertilizer contain P2O5=0.0003086 x Rx 100/10
1 gm fertilizer contain P2O5 =0.0003086 x R x 100/10 x 0.5
100gm fertilizer contain P2O5=0.0003086 x R x 100 x 100/10 x 0.5

Page 13 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

So
P2O5 (%) =0.618 x R (Where sample (solid) taken is 0.5g)
For liquid samples
P2O5 (%) =0.0618 x R
Whereas
Sample (liquid) taken is 5ml.

■ Precautions
This method gives erroneous results in case of liquid samples containing P2O5 contents more than
10%. In such case, first make appropriate dilutions then proceed further.

■ Reference / Related Documents:

● Pakistan standard for Single Super Phosphate (2nd edition) PS: 67-1996. PSQCA. Karachi

ESTIMATION OF TOTAL PHOSPHORUS FROM BIO-ORGANIC FERTILIZERS

■ Principle
This testing method is applicable to fertilizers containing organic matters. Test sample is
pretreated with nitric acid to convert total phosphorus into phosphate ions. Converted phosphate
ions can be determined as ammonium phosphomolybdate after precipitation with ammonium
molybdate solution. Precipitates are filtered, washed to acid free and dissolved in standardized
0.1N sodium hydroxide. The excess of which is back titrated against standardized 0.1N Sulphuric
acid to determine amount of phosphorus in fertilizer sample.
■ Equipment
 Weighing balance
 Volumetric flask-100 ml
 Volumetric flask 1000 ml
 Beaker-100 ml
 Bulb type pipette-10 ml
 Graduated pipette 10 ml
 Conical flask-250 ml
 Wash Bottle
 Whatman No.42 filter paper
 Funnel with stand
 Blue Litmus paper
 Burette 100 ml

Page 14 of 45
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AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Reagents
 Concentrated Nitric Acid
 Ammonium Molybdate Solution (3%): Dissolve 30-gram Ammonium Molybdate tetra
hydrate ((NH4)Mo7O24.4H2O, Analytical grade) salt in 1000ml volumetric flask and make
up volume by DI water up to the mark.
 Ammonium Nitrate Solution, (50 %): Dissolve 500-gram Ammonium Nitrate (NH4NO3,
80.04g/mol, Analytical grade) salt in 1000ml volume metric flask and make up the volume
with DI water up to the mark.(d)Phenolphthalein indicator(e)
 Standardized 0.1 N Sulphuric Acid
 Standardized 0.1 N Sodium Hydroxide
 Potassium Hydrogen Phthalate Solution, (0.1 N): Dissolve 20.423gram Potassium
Hydrogen Phthalate (C8H5KO4, 204.23g/mol Analytical grade) salt in 1000 ml volumetric
flask and make up volume with DI water up to the mark.
■ Procedure
Weigh accurately 0.5 g homogenized BOP fertilizer sample previously grinded and sieved
through 40 mesh sieves in 100 ml volumetric flask, add 5 ml concentrated nitric acid, add about
50 ml distilled water place the sample on hot plate and raise the temperature up to 65oC on hot
plate. Shake for 60 minutes on mechanical shaker. After shaking make volume up to mark
distilled water. Filter and take 10 ml solution from filtrate, in a 250 ml conical flask. Add 5 ml,
concentrated nitric acid and 15 ml, ammonium nitrate solution (50 %). Heat the contents gently
on a hot plate at 65oC and then add gradually 50 ml ammonium molybdate solution (3%). Shake
the conical flask during ammonium molybdate solution addition. Yellow precipitate of
ammonium phosphomolybdate will form depending on the concentration of phosphorus present in
the given BOP sample. Stay for one night. Next day filter the yellow precipitates using Whatman
No. 42 and wash with ice cold distilled water till the filtrate does not turn blue litmus to red. This
indicates that precipitates are now acid free. Now transfer the acid free precipitates along with
filter paper into the same conical flask. Care should be taken that the same conical flask should
also be acid free. Dissolve the precipitates completely in 0.1 N sodium hydroxide by adding 10 ml
each time. Note the amount of alkali used. Now add 2-3 drops of phenolphthalein indicator. Pink
color will develop. Titrate against 0.1 N Sulphuric acid with continuous shaking till colorless
end point. Note the volume of Sulphuric acid used.
■ Calculations
% P2O5=0.000309 x X -Y x 100 x 100 / 10 x 0.5
Where, X = 0.1N NaOH used to dissolve precipitate
Y = 0.1N H2SO4 used for back titration.
OR %P2O5= (x-y) x 0.618
If 0.5 gm fertilizer sample is used

Page 15 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Detail of Calculation
During chemical reaction out of 23 molecules of NaOH only one molecule of Na is used to
form Na (NH4) HPO4 which contain one molecule of P.
Therefore, ammonium phosphomolybdate precipitate contains Na and P in the ratio of 1:1. i .e,
normal solution of NaOH (23gm Na/L) =1 N solution of P (31g P / L).
So, 31/ 23 =1.3478g P/ L
1 N NaOH =1.3478x2.29g P2O5/ L (for P to P2O5 use 2.29)
-do-=3.0864g P2O5/ liter
-do-=0.003086g P2O5/ml
1 ml of 0.1 N NaOH =0.0003086g P2O5/ml
R ml of 0.1 N NaOH =0.0003086x R g P2O5 / ml (R = reading)
10ml of 0.1 sample contains = 0.000386 x R g P2O5(If 10 ml aliquot is
used).
1 ml of sample contains =0.0003086 x R/10
100ml of sample contains=0.0003086 x R x 100/10
0.5 gm BOP contain P2O5=0.0003086 x Rx 100/10 (where sample taken is
0.5 g)
1 gm BOP contain P2O5 =0.0003086 x R x 100/10 x 0.5
100gm BOP contain P2O5=0.0003086 x R x 100 x 100/10 x 0.5
So
P2O5 (%) =0.618 x R (Where sample taken is 0.5g)
■ Reference
 Pakistan standard for BOP.PS:5295/2017 (2ndRev.), PSQCA. Karachi.

ESTIMATION OF POTASSIUM IN POTASH FERTILIZER BY FLAME

PHOTOMETER METHOD

■ Principle
This test method is applicable to fertilizers containing potassium salts. Extract by adding water to
an analytical sample and determine the intensity of the emission line at a wavelength of 766.5 nm
or 769.9 nm produced in flame to quantify water-soluble potassium (W-K2O) in an analytical
sample.
■ Equipment
 Flame photometer
 Analytical balance
 Volumetric flask-100 ml, 500ml, 1000ml
 Beaker glass 100 ml, 500ml, 100ml
 Bulb type pipette 1ml, 5ml,10ml
 Wash bottle

Page 16 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

 Funnel with stand

 Filter paper sheet
■ Reagents
Potassium chloride: Use 1000 ppm Certified Reference Material (CRM) of potassium Chloride
Prepare a sub stock solution by taking 10 ml from 1000 ppm stoke solution and dilute to 100ml.
Series of working standard solutions from the sub-stock solution as follows:
Dilute 5, 10, 15-, 20-, and 25-mL sub-stock solution to 100-mL final volume of each by adding
DI water. These solutions contain 5, 10, 15, 20 and 25 ppm K, respectively.

■ Procedure
Dissolve 2.5 g ground potash fertilizer material in 200 ml distilled water in 500ml beaker. Cover
the beaker with a watch glass and heat on a hot plate to boil for about 15 minutes. After standing
to cool, transfer to a 250-mL volumetric flask with water. Give washings to the beaker with
distilled water and make volume of volumetric flask up to the marked line. Make further dilutions
if necessary.
■ Standard calibration curve
Optimize the instrument by adjusting the fuel and air flow. Adjust instrument read-out to zero for
blank and 100 for 25 ppm standard. Now take readings of 5, 10, 15, 20 and 25 ppm standards and
develop calibration curve accordingly.
Take readings of the sample filtrate and calculate the K concentration from standard calibration
curve.
■ Calculations
K (ppm) x dilution Factor x 1.2046
K2O% = 10000

■ Reference / Related Documents

● Testing Methods for Fertilizers (2016). Incorporated Administrative Agency. Food and
Agricultural Materials Inspection Center. Japan. Section: 4.3.3.a
● Standard operating manual of instrument.

ESTIMATION OF WATER-SOLUBLE ZINC IN FERTILIZER BY FLAME ATOMIC

ABSORPTION SPECTROPHOTOMETER

■ Principle. This test method is applicable to fertilizers that contain zinc contents as zinc
sulphate. Extraction is done by boiling test sample in distilled water. Zinc contents are determined

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Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

by flame atomic absorption spectrometry (FAAS) in which monochromatic radiation,

characteristic for the metal in question, is passed through a long, thin flame, into which the
sample solution is sprayed. A flame is produced in a pre-mix type burner with a 10cm long slit.
The burner head is aligned so that the radiations will pass exactly over this slit. These conditions
result in absorption of radiation that is selective for element. The extent of absorption will be
proportional to the number of ground state atoms present in the flame.
■ Reagents
● Certified Reference Material (CRM) of Zinc (1000 ± 5ppm Zn, stock solution). It should be
NIST traceable and manufactured by ISO certified company.
● Prepare stock solution of 100ppm in Deionized water and can be stored for 15 days. Electrical
conductivity (EC) of water should not be more than 20µS/cm.
● Prepare at least 3 working standards between 0 to 3ppm. Use graduated pipette for preparation
of working standards. Read the lower meniscus for colorless liquids keeping mark on pipette
at eye-level.
■ Equipment
● Analytical balance (with readout up to 3 decimals minimum)
● Hot Plate calibrated at 150 C0.
● Atomic Absorption Spectrophotometer
● Glass Beaker 150 mL (Tall form) and use glass lid while boiling.
● Measuring cylinder 100mL
● Volumetric flask 100mL, 500mL, 1000mL, 2000 mL
● Glass Funnel
● Filter Paper (Whatman No.42)
● Graduated and calibrated pipette 2ml, 5ml.
● All the glassware should be Pyrex, Class-A type.
● Sieve Mesh No. 40
● Mortar and pestle
■ Procedure
Sample preparation: Grind almost 100g of sample as it is, (do not dry or desiccate) and pass all
the ground sample from Mesh No. 40 sieve. Place 1.00 g well-ground test portion (2ml for liquid
sample) in 150 mL glass beaker (tall form). Add 75mL de-ionized water and boil for 30 minutes
(count time after boiling begins) on hot plate at 150 C0. Put watch-glass on beaker. Wash the
watch-glass into filtrate to avoid sample loss. Wash the beaker, watch-glass into 1 Liter
volumetric flask. Make the volume up to the mark with distilled water. Shake well and filter
through Whatman No. 42 filter paper. Re dilute if necessary.
Measurements: Optimize Atomic Absorption Spectrophotometer (AAS) parameters i.e., fuel
flow, lamp energy current, lamp orientation and burner height. Calibrate the AAS between 0 and
3ppm standards. R2 value of calibration curve should be 0.998 or higher otherwise recheck or
repeat. Measure readings between 0.3 to 2.8ppm. In case, reading is above or below this limit,

Page 18 of 45
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Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

dilute or concentrate the sample accordingly. Determine concentration of element in solution

(ppm) from calibration curve or digital concentration readout following the standard operating
parameters. Run the blank (D.I. water) between working standards and samples. Run the
reference salt as check sample. This is optional.

Element Wavelength (nm) Flame Range (ppm)

Zinc 213.8 Air-C2H2 0 - 3.0

■ Calculations
Zinc (% ) = Reading x dilution /10,000.

■ References / Related Documents

● Official Methods of Analysis of AOAC International, 20th Edition, 2016, Volume-1. Method
No. 2.6.01 (AOAC Official Method 965.09) Fertilizers, Chapter 2, Page 29-30
● Operating manual of Atomic Absorption Spectrophotometer

ESTIMATION OF ACID-SOLUBLE ZINC COPPER IRON AND MANGANESE IN

INORGANIC MATERIALS AND MIXED FERTILIZERS BY ATOMIC ABSORPTION
SPECTROPHOTOMETER
■ Principle
This test method is applicable to in-organic mixed fertilizers containing zinc , copper, iron, and
manganese. The process involves wet digestion with acid to release and solubilize the nutrients
and flame atomic absorption spectrometry technique is used for determination. Atomic absorption
spectrophotometry involves monochromatic radiation, characteristic for the metal in question, is
passed through a long, thin flame, into which the sample solution is sprayed. A flame is produced
in a pre-mix type burner with a 10cm long slit. The burner head is aligned so that the radiations
will pass exactly over this slit. These conditions result in absorption of radiation that is selective
for element. The extent of absorption will be proportional to the number of ground state atoms
present in the flame.
■ Reagents
● Concentrated HCl (Purity 37%)
● 2M HCL solution: Dissolve 165.8 ml of 37% pure HCl in 1 Liter volumetric flask and make
up to 1 L.
● 0.5M HCl Solution: Dissolve 82.89 ml of 37% pure HCl in 2 Liter volumetric flask and
make-up to 2 L.
● Certified Reference Material (CRM) of Zinc, Copper, Iron and Manganese (1000 ± 5ppm,
stock solution). CRM should be NIST traceable and manufactured by ISO certified company.

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SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

● Prepare stock solution of 100ppm in D.I. water and store for 15 days. Electrical Conductivity
of water should not be more than 20µS/cm.
● Prepare at least 3 working standards considering the detection range of respective element
given in table below. Use graduated pipette for preparation of working standards. Read the
lower meniscus for colorless liquids keeping mark on pipette at eye-level.
■ Equipment
● Analytical balance (with readout up to 3 decimals minimum)
● Hot Plate
● Atomic Absorption Spectrophotometer
● Glass Beaker 150 or 250 mL (Tall form) and use glass lid while boiling.
● Measuring cylinder 100ml
● Volumetric flasks 100mL, 250mL
● Glass Funnel
● Filter Paper (Whatman No.1 )
● Graduated and calibrated pipette 2ml, 5ml, 10mL.
● All the glassware should be Pyrex, Class-A type.
● Sieve Mesh No. 40
● Mortar and pestle
■ Procedure
Grind almost 100g of sample as it is, (do not dry or desiccate) and pass all the ground sample
from Mesh No. 40 sieve. Weigh 1g well-ground, homogenized test portion or 2ml liquid sample
into 100 mL glass beaker. Add 10 mL concentrated 37% pure HCl. Boil and evaporate solution
nearly to dryness on hot plate. Do not bake residue. Re-dissolve residue in 20 mL 2M HCl,
boiling gently if necessary. Wash the beaker, watch-glass into 100 ml volumetric flask. Make the
volume up to the mark with distilled water. Shake well and filter through Whatman No. 41 filter
paper. Measure absorbance of respective micronutrient directly or dilute with 0.5M HCl to obtain
solution within range of calibration curve by using instrument conditions for each element.
Determine concentration of element in solution (mg/L) from calibration curve or digital
concentration readout following the standard operating parameters.

Element Wavelength, A Flame Range µg/ml

Zinc 2138 Air-C2H2 0.5 to 5.0
Copper 3247 Air-C2H2 2 to 20
Iron 2483 Air-C2H2 2 to 20
Manganese 2795 Air-C2H2 2 to 20

■ Calculations:
Element % = Reading x dilution /10000.

Page 20 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Reference / Related Documents:

● Official Methods of Analysis of AOAC International, 20th Edition, 2016, Method No. 2.6.01-C
(AOAC Official Method 965.09), Fertilizers Chapter 2, Subchapter 6, Page 29-30
● Operating manual of instrument Atomic Absorption Spectrophotometer

ESTIMATION OF WATER-SOLUBLE FRACTION OF MICRONUTRIENTS (ZINC,

COPPER, IRON AND MANGANESE) BY FLAME ATOMIC ABSORPTION
SPECTROPHOTOMETER
■ Principle
This method is applicable to in-organic (synthetic) fertilizers containing salts of zinc, copper,
iron, and manganese. The process involves water extraction to solubilize the nutrients and atomic
absorption spectrophotometric method is applied for determination.
Flame atomic absorption spectrometry involves monochromatic radiation, characteristic for the
metal in question, is passed through a long, thin flame, into which the sample solution is sprayed.
A flame is produced in a pre-mix type burner with a 10cm long slit. The burner head is aligned so
that the radiations will pass exactly over this slit. These conditions result in absorption of
radiation that is selective for element. The extent of absorption will be proportional to the number
of ground state atoms present in the flame.
■ Reagents
● Certified Reference Material (CRM) of Zinc, Copper, Iron and Manganese (1000 ± 5ppm,
stock solution). CRM should be NIST traceable and manufactured by ISO certified company.
● Prepare stock solution of 100ppm in D.I. water and store for 15 days. Electrical Conductivity
of water should not be more than 20µS/cm.
■ Equipment
 Analytical balance
 Hot Plate
 Atomic Absorption Spectrophotometer
 Volumetric flask
 Funnel
 Filter Paper (Whatman No.1)
 Pipette
■ Procedure
Place 1.00g test portion into 100 mL glass beaker. Add 75mL D.I water and boil 30 minutes.
Filter in 1-liter volumetric flask, washing filter with D.I water. Make the volume up-to the mark
with D.I water. Re-dilute if necessary. Determine concentration of element in solution (mg/L)
from calibration curve or digital concentration readout following the standard operating
parameters.

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 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

Element Wavelength nm Flame Range µg/ml

Zinc 213.8 Air-C2H2 0.5-5
Copper 324.7 Air-C2H2 2-20
Iron 248.3 Air-C2H2 2-20
Manganese 279.5 Air-C2H2 2-20

■ Calculations
% element= (µg/ml) X dilution x 10-4

■ Reference / Related Documents:

 Official Methods of Analysis of AOAC International, 20th Edition, 2016, Method No. 2.6.01-
C(e1). (AOAC Official Method 965.09), Fertilizers Chapter 2, Sub Chapter-6. Page 29-30
 Operating manual of instrument Atomic Absorption Spectrophotometer

ESTIMATION OF CHARRED/ASHED FRACTION OF MULTI-MICROS (ZINC,

COPPER, IRON AND MANGANESE) BY FLAME ATOMIC ABSORPTION
SPECTROPHOTOMETER
■ Principle
Method is applicable to organic fertilizers containing multi-micros nutrients (minors). The
process involves furnace ashing of fertilizer to release/solubilize the nutrients and Atomic
absorption spectrophotometric method is applied for determination.
■ Reagents
● Certified Reference Material (CRM) of Zinc, Copper, Iron and Manganese (1000 ± 5ppm,
stock solution). CRM should be NIST traceable and manufactured by ISO certified company.
● Prepare stock solution of 100ppm in D.I. water and store for 15 days. Electrical Conductivity
of water should not be more than 20µS/cm.
■ Equipment
 Analytical balance
 Hot Plate
 Atomic Absorption Spectrophotometer
 Volumetric flask
 Funnel
 Filter Paper (Whatman No.42)
 Pipette
■ Procedure
Place 1 .00 g sample in 150 mL beaker (Pyrex, or equivalent). Char on hot plate and ignite 1-hour
at 500° with muffle door propped open to allow free access of air. Break up cake with stirring rod

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and dissolve in 10 mL HC1. Boil and evaporate solution nearly to dryness on hot plate while
covering the beaker with watch-glass. Do not bake residue. Re-dissolve residue in 20 mL 2M
HC1, boiling gently, if necessary. Wash the beaker, watch-glass into 100 ml volumetric flask.
Make the volume up to the mark with distilled water. Shake well and filter through Whatman No.
41 filter paper.
Measure absorption of solution directly or dilute with 0.5M HC1 to obtain solutions within ranges
of instrument.
Element Wavelength nm Flame Range µg/ml
Zinc 213.8 Air-C2H2 0.5-5
Copper 324.7 Air-C2H2 2-20
Iron 248.3 Air-C2H2 0.2-2
Manganese 279.5 Air-C2H2 2-20

■ Calculation
% element= (µg/ml) X dilution x 10-4

■ Reference / Related Documents:

 Official Methods of Analysis of AOAC International, 20th Edition, 2016, Method No. 2.6.01-
C(b). (AOAC Official Method 965.09), Fertilizers Chapter 2, Sub Chapter-6. Page 29-30 .
 Operating manual of instrument Atomic Absorption Spectrophotometer.

ESTIMATION OF CHELATED ZINC IN CHELATED ZINC FERTILIZER BY FLAME

ATOMIC ABSORPTION SPECTROPHOTOMETER
■ Principle
This method is applicable to fertilizers containing chelated zinc. Mineral-Zn fraction is masked by
Na2CO3 solution and filtrate is directly run for analysis of chelated fraction through atomic
absorption spectrophotometer.

Zn-EDTA + ZnSO4 + Na2CO3

(0.1 Molar.
→ Zn-EDTA + ZnCO3 + Na2SO4
pH 8.9)

Zn-EDTA Acid Hydrolysis → Total chelated Zinc

■ Equipment
● Volumetric flask

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SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

● Pipette
● Analytical balance
● Atomic absorption spectrophotometer

■ Reagents
● Certified Reference Material (CRM) of Zinc (1000 ± 5ppm Zn, stock solution). CRM should
be NIST traceable with valid certificate of analysis and manufactured by ISO certified
company.
● Prepare stock solution of 100ppm Zn in D.I. water and store for 15 days. Electrical
Conductivity of water should not be more than 20µS/cm.
● Prepare working standards at least 3 and between 0 to 3ppm. Use graduated pipette for
preparation of working standards. Read the lower meniscus for colorless liquids keeping mark
on pipette at eye-level.
● Na2CO3 (0.1M): Dissolve 21.2g Na2CO3 in 2-liter deionized water
● H2SO4 AR grade
■ Procedure
Take 1.25 g homogenized sample previously ground and sieved through Mesh No. 40 (or 2ml
filtered liquid sample) in 250ml flask. Add 100 ml Na2CO3 (0.1M) solution and shake well. Make
volume with Na2CO3 (0.1M) solution up to the mark. Let stay sample for 10 minutes. Non-
chelated zinc will precipitate, filter the solution through Whatman filter paper No.42. Take 1ml of
filtrate in 100mL volumetric flask and add 5ml conc. H2SO4 and make volume 100ml using
distilled water. Take reading on Atomic Absorption Spectrophotometer.
■ Calculation
Zinc (% ) = Reading x dilution /10,000
Whereas

For solid 250 x 100 = 20000 = Dilution Factor 2

1.25 1 10000

For Liquid 250 x 100 = 5000 = 1 = Dilution Factor 1.25

2ml 1 10000 2
■ References/Related Documents
● Vogel’s Textbook of quantitative chemical Analysis, Sixth Edition. J Mendham, R C Denney, J
D Barnes, M J K Thomas
● Official Methods of Analysis of AOAC International, 20th Edition, 2016, Method No. 2.6.01
(AOAC Official Method 965.09), Fertilizers Chapter 2, Page 29-30
● M. S. A. Khan, M. A. Qazi, S.M. Mian, M. Akram, Comparison of Three Analytical Methods
for Separation of Mineral and Chelated Fraction from an Adulterated Zn-EDTA Fertilizer,
Journal of Chemical Society of Pakistan, 35, 2 (2013).

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ESTIMATION OF CHELATED IRON IN CHELATED FERTILIZER BY FLAME

ATOMIC ABSORPTION SPECTROPHOTOMETER
■ Principle
This method is applicable to fertilizers containing chelated-Fe. Test portion is dissolved in water
and non-chelated Fe is precipitated as Fe(OH)3, at pH 8.5 and removed. Chelated Fe is
determined by atomic absorption spectrophotometer using standard solutions containing
Na2H2EDTA.

■ Equipment
 Analytical balance (with readout up to 3 decimals minimum)
 Atomic Absorption Spectrophotometer
 Glass Beaker 150 or 250 mL (Tall form).
 Measuring cylinder 100ml
 Volumetric flasks 100mL, 250mL, 1L
 Glass Funnel
 Filter Paper (Whatman No.42 )
 Graduated and calibrated pipette 2ml, 5ml, 10mL.
 Sieve Mesh No. 40
 Mortar and pestle
■ Reagents
 Sodium Hydroxide Solution: 0.5M, Dissolve 20g NaOH in H2O and dilute to 1L.
 Disodium EDTA solution: 0.66%, Dissolve 0.73g Na2H2EDTA. 2H2O in H2O and dilute to
100mL.
 0.5M HCl Solution: Dissolve 82.89 ml of 37% pure HCl in 2 Liter volumetric flask and make
up to 2 L.
 Iron Stock Solution: Certified Reference Material (CRM) of Iron (1000 ppm Fe). CRM
should be manufactured by ISO certified company and NIST traceable.
 Intermediate Solution: 100µg Fe/100mL, Pipet 10mL Fe stock solution and 10mL
Na2H2EDTA. 2H2O solution into 100mL volumetric flask and dilute to volume with water.
 Working Solutions: Dilute aliquots of intermediate solutions with 0.5M HCl to make ≥ 4
standard solutions within range of determination (2-20 µg Fe/mL)

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■ Procedure
Weigh 1g well-ground, sieved through Mesh No. 40 and homogenized test portion or 2ml liquid
sample into 250mL tall-form beaker. Wet with 2-3 drops of ethanol and dissolve in 100 mL H2O.
Add 4 drops of 30% H2O2, mix and adjust pH of solution to 8.5 with 0.5M NaOH. If pH drifts
above 8.8, discard solution and repeat analysis. Transfer solution to 250mL volumetric flask.
Dilute to volume with water and mix. Filter solution through quantitative paper. Pipet 1mL filtrate
into 100mL volumetric flask and dilute to volume with 0.5M HCl. Determine concentration of
iron in solution (mg/L) from calibration curve or digital concentration readout following the
standard operating parameters of atomic absorption spectrometer.

Element Wavelength, A Flame Range µg/ml

Iron 2483 Air-C2H2 2 to 20

■ Calculation
Chelated Fe % = Reading x dilution factor/10000.

■ References / Related Documents

 Official Methods of Analysis of AOAC International, 20th Edition, 2016, Method No. 2.6.16
(AOAC Official Method 983.03), Fertilizers Chapter 2, Page 35

ESTIMATION OF CHELATED COPPER AND MANGANESE IN CHELATED

FERTILIZER BY FLAME ATOMIC ABSORPTION SPECTROPHOTOMETER

■ Principle
Sample is dissolved in water and pH of the solution is adjusted at 8.5-8.8. Non-chelated mineral
fraction is precipitated and removed. Chelated fraction is detected by Atomic Absorption
Spectrophotometer.
■ Equipment
 Volumetric flask ,
 Pipette, Beakers
 Analytical balance
 Atomic absorption spectrophotometer
■ Reagents
 Sodium hydroxide solution. 0.5N: . Dissolve 20 g NaOH in distilled water and dilute to 1
liter.
 Hydrogen peroxide solution: 30%

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■ Procedure
Weigh 0.5 g sample (ca 40 mg) into 200 mL tall-form beaker. Wet with 2-3 drops of alcohol and
dissolve in 100 mL DW. Add 4 drops of 30% H2O2, mix and adjust pH of solution to 8.5-8.8 with
0.5N NaOH. If pH drifts above 8.8, discard solution and repeat analysis. Transfer solution to 250
mL vol. flask, dilute to volume with DW, and mix. Filter solution using Whatman 42 filter paper.
Dilute further, where necessary. Use air-acetylene flame and detect concentration from either
calibration curve or digital readout. In same manner, run blank on all reagents used and take
reading on atomic absorption spectrophotometer following standard operating procedure.

Element Wavelength nm Flame Range µg/ml

Copper 324.7 Air-C2H2 2-20
Manganese 279.5 Air-C2H2 2-20

■ Calculations
% element = (µg/ml) X dilution x 10-4

■ References / Related Documents

● María Villén, Juan José Lucena, M. Carmen Cartagena, Raquel Bravo, Josemaría García-Mina,
and M. Ignacia Martín de la Hinojosa, 2007.Comparison of Two Analytical Methods for the
Evaluation of the Complexed Metal in Fertilizers and the Complexing Capacity of Complexing
Agents. J. Agric. Food Chem. 2007, 55, 14, 5746–5753.
● Modified method based on AOAC method 983.03.

ESTIMATION OF ACID-SOLUBLE FRACTION OF CALCIUM AND MAGNESIUM BY

FLAME ATOMIC ABSORPTION SPECTROPHOTOMETER
■ Principle
This method is applicable to in-organic fertilizers. The process involves wet digestion with acid to
release and solubilize the nutrients and atomic absorption spectrophotometric method is applied
for determination.
■ Reagents
● Certified Reference Material (CRM) of Calcium and Magnesium (1000 ± 5ppm Ca/Mg,
stock solution). CRM should be NIST traceable with valid certificate of analysis and
manufactured by ISO certified company.
● Prepare stock solution of 100ppm of calcium and magnesium in D.I. water and store for 15
days. Electrical Conductivity of water should not be more than 20µS/cm.
● Prepare working standards at least 3 and between 0 to 3ppm. Use graduated pipette for
preparation of working standards. Read the lower meniscus for colorless liquids keeping mark
on pipette at eye-level.
■ Equipment
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SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

 Analytical balance
 Hot Plate
 Atomic Absorption Spectrophotometer
 Volumetric flask
 Funnel
 Filter Paper (Whatman No.42)
 Pipette
■ Procedure
Dissolve 1 .00 g well ground sample in 10 mL HC1 in 150 mL beaker. Boil and evaporate
solution nearly to dryness on hot plate. Do not bake residue. Re-dissolve residue in 20 mL 2M
HC1, boiling gently, if necessary. Filter through fast paper into 100 mL vol. flask, washing paper
and residue thoroughly with H2O. Measure absorption of solution directly or dilute with 0.5M
HC1 to obtain solutions within ranges of instrument.
If Ca is to be determined add enough La stock solution to make final dilution 1% La.

Element Wavelength nm Flame Range µg/ml

Calcium 422 Air-C2H2 2-10
Magnesium 285 Air-C2H2 0.2-2.0

■Calculation
% element= (µg/ml) X dilution x 10-4

■ Reference / Related Documents

 Official Methods of Analysis of AOAC International, 20th Edition, 2016, Method
No.2.6.01- C (e1). (AOAC Official Method 965.09), Fertilizers Chapter 2, Sub Chapter-6.
Page 29-30
 Operating manual of instrument Atomic Absorption Spectrophotometer

ESTIMATION OF WATER-SOLUBLE BORON CONTENT IN FERTILIZER

■ Principle
This test method is applicable to fertilizers containing boron or borate. Boron is extracted by
adding water to test samples and masking with ammonium acetate buffer solution. Extracted
boron is measured spectrophotometrically, a technique that used to measure the concentration of
solutes in solution by measuring the amount of light that is absorbed or transmitted by the
solution in a cuvette placed in the spectrophotometer.
■ Equipment
● Analytical balance (with readout up to 3 decimals minimum)
● Spectrophotometer
● Polypropylene flasks 500, 1000mL

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● Volumetric flask (Pyrex) 100 mL, 500mL, and 1000mL flasks should be pretreated with HCl.
● Polypropylene tube with cap 15 ml
● Micropipette 100µL
● Glass Beaker
● Filter Paper Whatman No 42 or equivalent
● Funnel with stand
● Graduated and calibrated pipette 2ml, 5ml, 10mL.
■ Reagents
● Certified Reference Material (CRM) of Boron (1000 ± 5 mg B/L) with valid Certificate of
Analysis (COA) can be used to prepare stock solution of 100 mg B/L. It should be NIST
traceable and manufactured by ISO certified company.
● Working solution: 0, 5, 10, 15, 20, 25, 30, 45 µg/ml. Pipet 5, 10, 15, 20, 25, 30- and 45-ml
from stock solution into 100 ml volumetric flask. Dilute to volume with water, mix well and
transfer to plastic bottle. Electrical Conductivity of water should not be more than 20µS/cm.
● Azomethine H color reagent: Dissolve 0.9 g Azomethine H and 2.0 g ascorbic acid in100 ml
water. Store in refrigerator and discard after 14 days.
● Buffer masking solution: Dissolve 140 g Ammonium Acetate, 10 g Potassium Acetate, 4 g
Nitrilotriacetic acid, disodium salt 99+ %, 10 g (Etheline dinitrilo) Tetra acetic acid, and 350
ml 10 % Acetic acid in water and dilute to 1 liter with water. Solution is stable.
● Color developing reagent: Place 35 ml Azomethine H color reagent and 75 ml buffer masking
solution into 250 ml volumetric flask and dilute to volume with water. Prepare fresh daily.
■ Procedure
Preparation of test solution: Weigh 2.0 g, ground, sieved test portion (2ml for filtered liquid
sample) to 150 ml glass beaker add 50 ml water, and boil ca 10 minutes. Filter hot through
Whatman No 40 or equivalent, into 500mL or 1000 mL volumetric flask. Wash precipitate with
hot boiled water until volume in the flask is ca 495 ml or 995 ml. Cool and add 1.0 ml HCl, dilute
to volume with water and mix. Transfer to plastic bottle immediately; dilute if required.
Determination: pipet 100 µl aliquots of 0, 5, 10, 15, 20, 25, 30 , 35 and 45µg B/ml standards and
100µl aliquots of test solution into separate 10 ml Polypropylene tube. Add 5.0 ml colour
developing reagents by automatic pipette/dispenser and let stand for one hour at room
temperature. Read Absorbance at 420 nm against water. Correct for reagent blank (0 mg B/ml).
Construct standard curve by plotting Absorbance against µg/ml standard and read concentration
(µg/ml) of test solution from standard curve.
■ Calculation
B % = (µg/ml from standard curve) x dilution factor x 10-4
■ Reference / Related Documents
● Official Methods of Analysis of AOAC International, 20th Edition, 2016. Method No. 2.6.04
(AOAC Official Method 982.01), Fertilizers Chapter 2, Subchapter 6, Page 31-32.
● Ryan, J., George Estefan, and Abdul Rashid. 2001. Soil and Plant Analysis Laboratory
Manual. Second Edition. Jointly published by the International Center for Agricultural

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AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
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SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

Research in the Dry Areas (ICARDA) and the National Agricultural Research Center (NARC).
Available from ICARDA, Aleppo, Syria.
● Standard operating manual of Spectrophotometer

GRAVIMETRIC METHOD FOR THE DETERMINATION OF HUMIC ACID

CONTENT IN SOLID AND LIQUID FERTILIZERS

■ Principle
Humic Acid is dissolved in weak extraction solution. Particulate/Colloidal/inert matter in the
sample is removed by subsequent filtration/centrifugation. Finally precipitates of actual humic
acid are obtained by the addition of Nitric Acid (HNO3) and humic acid contents are calculated
gravimetrically.

■ Equipment
● Weighing balance
● Mechanical shaker
● Oven
● Desiccator
● Centrifuge machine
● Volumetric flask100 ml, 1000ml
● Beaker 100 ml
● Wash Bottle
● Filter paper Whatman No.42
● Funnel with stand

■ Reagents
● Concentrated Nitric Acid
● Sodium hydroxide
● Ethanol
● Diethylenetriamine Penta acetic acid (DTPA)
● Humic Acid Standard (Aldrich)
● Extraction solution 0.05M (Dissolve 2g NaOH, 20ml Ethanol and 4ml of 0.001M DTPA in 1-
liter deionized water)

■ Procedure
Grind humic acid sample and pass through 30 mesh sieve. Weigh accurately 0.5 g sample in 100
ml volumetric flask and in case of liquid sample take 5ml after filtration. Add 50ml extraction
solution and shake the contents for one hour using mechanical shaker @ 270 rpm. Make volume
up to mark with extraction solution. Filter/centrifuge (20 minutes @ 4000 RPM) the solution to

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remove the colloidal/particulate/inert matter. Add concentrated Nitric Acid (HNO3) in filtrate until
the pH drops to 1.0. Keep the sample uninterrupted for 2 hours to complete the reaction. Humic
acid will precipitate. Oven dries the filter paper Whatman No. 42 till constant weight and record
the weight. Collect the precipitates by filtration through Whatman No. 42 filter paper or
centrifuge (20 minutes @ 4000 RPM). Dry the precipitates in oven at 105oC till constant dry
weight. Finally record the weight of dry precipitates.
■ Calculations
Weight of oven dry precipitates
Humic Acid (%) = x 100
Weight of sample taken
Whereas:

Weight of dry precipitate = weight of oven dry precipitate with - weight of oven dry
filter paper filter paper

■ Reference / Related Documents

● F.J. Stevenson, J. Environ. Quality, 1972, 1, 333.
● A.K. Fataftah, PhD Thesis, Northeastern University, Boston, 1997.
● T. L. Senn and A. R. Kingman, A Review of Humus and Humic Acid Research,
● www.humates.com/methodology.html

ESTIMATION OF ORGANIC MATTER CONTENT IN COMPOST

■ Principle
This method is applicable to compost and other products containing organic matter. Organic
matter is measured by loss of weight on ashing at 550 to 600 Co.

■ Equipment
● Crucible
● Balance
● Oven
● Muffle furnace
● Desiccator
■ Procedure
Weigh clean dry crucible (W1). Add 5g of 2mm particle sized manure sample previously ground
and sieved. Ovens dry at 105Co for 4hrs. Weigh sample and crucible. This yields the oven dry

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weight (W2). Place the same crucible in furnace at 550 to 600 Co for 6 hrs. The crucible with ash
is cooled in desiccator and weighed. This yields the ash weight (W3). Run a standard sample of
known value with each group of samples.

■ Calculations
Organic matter (%) = 100 – Ash (%)

W3 – W1
Ash (%) = X 100
W2 – W1

Organic matter value

Organic Carbon (%) =
1.724

Whereas
Factor 1.724 is derived from the ratio of Organic Carbon present in Organic matter.
Organic matter contains 58% organic carbon.
■ Precautions
Muffle furnace temperature must not exceed 600 oC.

■ Reference / Related Documents

● Official Methods of Analysis of AOAC International, 20th Edition, 2016. Method No.
(AOAC Official Method 967.05), Fertilizers Chapter 2 Page 54
● Standard operating manual of oven/furnace.

DETERMINATION OF CATION EXCHANGE CAPACITY OF ORGANIC MATTER/

COMPOSTS
■ Principle
Cation exchange capacity is measure of total amount exchangeable cations that can be held by
compost, expressed as milliequivalents/100g air-dried compost. Sample portion is shaken with
0.5M HCl to remove bases and to saturate sorption complex with H+ . Excess acid is removed,
absorbed H+ is replaced with Ba+2 titrated with 0.1M NaOH, using phenolphthalein indicator.
■ Equipment
 Weighing balance
 Volumetric flask-100 ml
 Beaker-100 ml
 Bulb type pipette-10 ml
 Conical flask-250 ml
 Wash Bottle

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SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

 Whatman No.42 filter paper

 Funnel with stand 3.
■ Reagent
Dilute hydrochloric acid (0.5M) Dilute 42 ml HCl to 1L with H2O
Barium acetate solution (0.25M) Dissolve 64g Ba(CH3 COO)2 in H2O and dilute to 1 Liter.
Sodium hydroxide standard solution (0.1M) Prepare and standardize.
■ Method
Place 2g of air-dried, ground, thoroughly mixed test sample in 300 mL Erlenmeyer flask. Add
100mL of 0.5M HCl solution. Stopper the flask and shake mechanically for 30 minutes. Filter and
wash the test portion with 100 mL portion H2O until 10mL wash shows no precipitation with 3ml
of 1% AgNO3. Discard filtrate. Immediately transfer moist sample to 300mL Erlenmeyer flask by
puncturing apex of paper and forcing moist sample through funnel stem into flask, using spray
bottle containing 100mL 0.25M Ba(CH3COO)2. Stopper flask and shake mechanically 15
minutes. Filter and wash with three 100mL portions H2O. Titrate against 0.1M NaOH using 5
drops of phenolphthalein indicator to first pink end point.
■ Calculation
CEC Me/100g = NaOH used (mL) x molarity of NaOH x 100 / Sample taken (gm)
■ Precautions / safety requirements
 Analyze Certified Reference Material along with samples.
 Take ample quantity of sample (approximately 200g) for grinding. Care should be taken that
all the sample taken for grinding must pass through sieve to obtain homogeneous sample.
 Standardize 0.1M NaOH against 0.1M Potassium Hydrogen Phthalate.
■ Reference / Related documents
 Official Methods of Analysis of AOAC International, 20th Edition, 2016. Method No. 2.7.13
(AOAC Official Method 973.09), Fertilizers Chapter 2, Subchapter 7, Page 56.

ESTIMATION OF SULPHUR IN SOP FERTILIZER SAMPLE

■ Principle
The testing sample is dissolved in deionized water and treated with Barium Chloride solution in
the presence of concentrated HCl. White precipitates of Barium Sulphate are produced which are
weighed to calculate the amount of Sulphur in sample.
■ Apparatus.
● Volumetric Flask 250 mL, 1 L
● Beaker 250mL, 500mL
● Pipette 2mL
● Muffle furnace
● Whatman No. 41
● Porcelain crucible

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■ Reagent
● Barium Chloride Solution: Dissolve 122g BaCl2 in deionized water and dilute to 1 Liter.
● Hydrochloric Acid (HCl) concentrated:

■ Procedure
1. Weigh 4g of Sulphate of Potash (SOP) fertilizer sample and dissolve in water to make volume
250mL. Mix well and filter through Whatman No. 41
2. Take 20mL of filtrate in 250 mL beaker and add 100mL deionized water and 2mL HCl
(Conc.).
3. Boil the solution for 5 minutes.
4. Add 50mL BaCl2 solution and keep boiling for further 5 minutes.
5. Cover beaker with cover glass and place in water bath for 1hr at 80 oC.
6. Filter the liquid through Whatman No.41
7. Wash precipitates on filter paper with distilled water until washings become chloride free
(Check precipitates with AgNO3 solution)
8. Place filter paper on crucible previously conditioned at 800 Co and weigh “W1”
9. Dry and Ignite for 1 hour at 800 Co in furnace.
10. Cool in desiccator and weigh as “W2”

■ Calculation
W2-W1 X 250 X 32 X 100
Sulphur (%) =
Weight of SOP taken (4g) X 20 mL X 233

■ Precautions
 Run the analytical potassium sulfate (99% pure with certificate of analysis) in every batch
along with sample to check the recovery of Sulphur. Use the correction factor according to the
recovery of Sulphur in pure K2SO4 .
 Run the blank

■ References/Related Documents
● Diagnosis and Improvement of Saline and Alkali soils, USDA, Handbook No. 60 pp146
● AOAC-2.6.28, Method 980.02, 17th edition, Determination of Sulphur in Fertilizer

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SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

● Pakistan Standard Specification for Potassium Sulphate fertilizer grade, 2nd Revision, PSQCA,
Karachi, PS:1501-2011 (R) ICS: 65.080

ESTIMATION OF CHLORIDES IN SULPHATE OF POTASH FERTILIZER SAMPLE

■ Principle
The testing sample is dissolved in Deionized water and titrated against standardized silver nitrate
solution. Silver reacts with chloride and forms white precipitates. As soon as all the chlorides are
consumed, additional Silver reacts with chromate to form brick red colour precipitates. The
endpoint for chloride analysis is the initiation of brick red colour. The amount of silver nitrate
consumed, and its normality is used to quantify chlorides in the sample.
■ Equipment
● Conical Flask 250 mL
● Pipette 2mL, 10 mL
● Burette 25mL
● Cylinder 50mL, 100mL
● Volumetric Flask 1000mL
■ Reagent
● Silver Nitrate 0.05N: Dissolve 8.4935g AgNO3 crystals in deionized water and dilute to 1
liter. Standardize against the 0.05 N NaCl solution using Potassium Chromate indicator till the
endpoint of brick red colour.
● Sodium Chloride Standard Solution 0.05N: Dissolve 2.9225g NaCl (Previously dried at
105oC for 1 hr.) and dilute to 1 liter .
● Potassium Chromate indicator: Dissolve 5g Potassium Chromate in 100mL deionized water
and add AgNO3 until a slight red precipitate is appeared. Allow the solution to stand for 24
hrs. and then filter.
● Phenolphthalein Indicator: Dissolve 0.1g of solid Phenolphthalein in 100mL of 95% ethanol
● Sulphuric Acid 0.02 N: Dilute 200mL of 0.1N H2SO4 to 1 liter.
● Sodium Hydroxide 0.02N: Dilute 200mL of 0.1N NaOH to 1 liter.
■ Procedure
1. Weigh 1g ground sample of Sulphate of Potash (SOP) fertilizer in 1-liter volumetric flask. Add
approximately 500 mL deionized water and shake on mechanical shaker for 30 minutes at 270
RPM. Make up the volume up to the mark and mix well. Filter if necessary.
2. Take 100mL filtered sample in conical flask using volumetric flask (100mL) and add 3-4 drops
of phenolphthalein indicator. If solution turns pink, neutralize it with 0.02N H2SO4 but if
solution remains colourless, first make alkaline with 0.02N NaOH and then neutralize with
0.02N H2SO4. (pH of the solution should be 7 to 8.3)

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3. Add 1 mL Potassium Chromate indicator and shake. Titrate against 0.05N AgNO3 until brick
red end point appears. Note the volume of AgNO3 used.

■ Calculation
The percentage of chloride is calculated as following:

(Vol of AgNO3 used - Blank) X 0.05 X 35.45 X1000 X 100

Chloride (% as Cl) =
Weight of SOP taken X mL of sample taken X 1000

■ Precautions
1. Always standardize AgNO3 against NaCl before use.
2. Take aliquot/sample using volumetric flask (100mL)
3. Run the blank and subtract the AgNO3 used from sample reading.
4. Run the NaCl (pure salt) in every batch along with sample to check the recovery of chloride.
Chloride in NaCl should be 60.66%.
5. Use the correction factor according to the recovery of Cl in NaCl.
6. Titration should be stopped when first trace of red-brown colour is observed.
7. Keep the AgNO3 in dark bottle as it is photosensitive.

■ References/Related Documents
● Diagnosis and Improvement of Saline and Alkali soils, USDA, Handbook No. 60 pp146
● AOAC-2.6.09, 17th edition, Method No. 928.02 Determination of chloride in Fertilizer
● Pakistan Standard Specification for Potassium Sulphate fertilizer grade, 2nd Revision, PSQCA,
Karachi, PS:1501-2011 (R) ICS: 65.080

ESTIMATION OF PACLOBUTRAZOL IN PLANT GROWTH REGULATOR SAMPLES

USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

■ Principle
The testing sample is dissolved in mobile phase Acetonitrile: water 50% :50%. Then the liquid
chromatographic separation and determination of Paclobutrazol is conducted with UV detector.
■ Equipment
● High performance liquid chromatography with UV-225nm wavelength detector
● C-18 or equal grade
● Filter: 0.45um
● Sonicator

Page 36 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Reagent
● Acetonitrile: HPLC grade
● Water: HPLC Grade
● Certified Reference Material of Paclobutrazol with valid certificate of analysis and NIST
traceable
■ Operating conditions
● Mobile phase: Acetonitrile: water = 50%: 50%
● Flow: 1.2 ml/min
● Detecting wavelength: 225 nm
● Injection-volume: 20ul
● Retention time: 8 minutes
■ Procedure
1. Standard solution: Weigh about 0.05g Paclobutrazol standard and put it into 50ml measuring
flask. Add approximately 25ml mobile phase and sonicate for 5 minutes. Make volume up to
the mark with mobile phase and shake it gently.
2. Testing sample: Dilute appropriate quantity of testing sample in 50ml measuring flask using
mobile phase so that its concentration fell within the concentration range of standard solution.
Sonicate for 5 minutes. Make the volume with mobile phase up to the mark and shake it gently.
3. Determination: Run the mobile phase for 10 minutes following prescribed operating
conditions. Inject the standard solution and test sample when the base line becomes stable.
Calculate the Peak area value of standard and test sample.

■ Calculation
The percentage of paclobutrazol is calculated as following:

Peak Area of Sample Weight of Standard

Paclobutrazole = X X Purity (%)
Peak Area of Standard Weight of Sample

■ References/Related Document
● Sigma-Aldrich Laborchemikalien GmbH, Quality Management SA-LC. Certificate of Analysis

Page 37 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

ESTIMATION OF NAPHTHYL ACETIC ACID (NAA) IN PLANT GROWTH

REGULATOR SAMPLES USING HIGH PERFORMANCE LIQUID
CHROMATOGRAPHY

■ Principle
The testing sample is dissolved in mobile phase Acetonitrile: water 30% :70%. Then the liquid
chromatographic separation and determination of NAA is conducted with UV detector
■ Equipment
 High performance liquid chromatography with UV-255nm wavelength detector
 Column C-18; 5µm or equal grade
 Filter: 0.45um
 Sonicator
■ Reagent
 Acetonitrile: HPLC grade
 Water: HPLC Grade
 Certified Reference Material of NAA with valid certificate of analysis and NIST traceable.
■ Operating conditions
 Mobile phase: Acetonitrile: water = 30%: 70%
 Flow: 1.0 ml/min
 Detecting wavelength: 255 nm
 Injection-volume: 10ul
 Retention time: 2.5 minutes
■ Procedure
1. Standard solution
Weigh about 0.01g NAA standard and put it into 25ml measuring flask. Add approximately
20ml mobile phase and sonicate for 5 minutes. Make volume up to the mark with mobile phase
and shake it gently.
2. Testing solution
Dilute appropriate quantity of testing sample in 25ml measuring flask using mobile phase so
that its concentration fell within the concentration range of standard solution. Sonicate for 5
minutes. Make the volume with mobile phase up to the mark and shake it gently.
3. Determination
Run the mobile phase for 10 minutes following prescribed operating conditions. Inject the
standard solution and test sample when the base line becomes stable.

Page 38 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Calculation
The percentage of NAA is calculated as following:

Peak Area of Sample Weight of Standard

Naphthaleneacetic Acid = X X Purity (%)
Peak Area of Standard Weight of Sample

■ References / Related Documents

Sigma-Aldrich Laborchemikalien GmbH, Quality Management SA-LC. Certificate of Analysis

ESTIMATION OF MEPIQUAT CHLORIDE IN PLANT GROWTH REGULATOR

SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

■ Principle
The testing sample is dissolved in water (HPLC grade) and determination of Mepiquat chloride is
carried out using UV detector.
■ Equipment
 High performance liquid chromatography with UV-191nm wavelength detector
 Column C-18 or equal grade
 Filter: 0.45um
 Sonicator
■ Reagent
 Acetonitrile: HPLC grade
 Water: HPLC Grade
 Certified Reference Material of Mepiquat Chloride with valid certificate of analysis and NIST
traceable
■ Operating conditions
 Mobile phase: Acetonitrile 10 % in HPLC water
 Flow: 1.0 ml/min
 Detecting wavelength: 191 nm
 Injection-volume: 20µl
 Retention time: ~2.0 minutes

Page 39 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Procedure
1. Standard solution
Weigh about 0.20g Mepiquat chloride standard and put it into 50ml measuring flask. Add
approximately 25 mL water and sonicate for 5 minutes. Make volume up to the mark with
water and shake it gently.
2. Testing sample solution
Dilute appropriate quantity of testing sample in 50ml measuring flask using water so that its
concentration fell within the concentration range of standard solution. Sonicate for 5 minutes.
Make the volume with water up to the mark and shake it gently.
3. Determination
Run the mobile phase for 10 minutes following prescribed operating conditions. Inject the
standard solution and test sample when the base line becomes stable.
■ Calculation
The percentage of Mepiquat chloride is calculated as following:

Peak Area of Sample Weight of Standard

Mepiquat Chloride = x x Purity %
Peak Area of Standard Weight of Sample
■ References / Related Document
 Sigma-Aldrich Laborchemikalien GmbH, Quality Management SA-LC. Certificate of Analysis
 Karasali, H. & Ioannou, S. 2009. HPLC determination of mepiquat chloride in commercial
pesticide formulations. Bulletin of environmental contamination and toxicology, 83, 636.

ESTIMATION OF GIBBERELLIC ACID IN PLANT GROWTH REGULATOR

SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
■ Principle
The testing sample is dissolved in mobile phase and determination of gibberellic acid is carried
out using UV detector.
■ Equipment
 High performance liquid chromatography with UV-206nm wavelength detector
 Reversed Phase C-18
 Filter: 0.45µm
 Sample injector: 20µl

Page 40 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

■ Reagent
 Acetonitrile: HPLC grade
 Certified Reference Material of gibberellic acid with valid certificate of analysis and NIST
traceable
■Operating conditions
 Mobile phase: Acetonitrile and acidic water (0.01% H3PO4) in the ratio of 60:40
 Flow: 0.6 ml/min
 Detecting wavelength: 206 nm
 Injection-volume: 20µl
 Run time: 10 minutes.
■ Procedure
1. Prepare standard solution.
Weigh about 0.10g Gibberellic standard and put it into 50ml measuring flask. Add
approximately 25 mL Acetonitrile and sonicate for 5 minutes. Make volume up to the mark
and shake it gently.
2. Prepare testing sample.
Dilute appropriate quantity of testing sample in 50ml measuring flask so that its concentration
fell within the concentration range of standard solution. Sonicate for 5 minutes. Make the
volume up to the mark with acetonitrile and shake it gently.
3. Determination
Run the mobile phase for 10 minutes following prescribed operating conditions. Inject the
standard solution and test sample when the base line becomes stable.
■ Calculation
The percentage of Mepiquat chloride is calculated as following:

Peak Area of Sample Weight of Standard

Gibberellic Acid = x x Purity %
Peak Area of Standard Weight of Sample

■ References/Related Documents
 K. Bhalla., R. Agarwal, Quantitative determination of gibberellins by high performance liquid
chromatography from various gibberellins producing strains. Environmental Monitoring and
Assessment. August 2009

Page 41 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

APPENDIX-1

Figure SEQ Figure \* ARABIC 1: Fee

Analysis Geo-referenced locations of eight primary and one
Receipt (Template)

Agriculture Department, Government of the Punjab

Soil & Water Testing Laboratory for Research,

Lab ID:
. Ph & Fax #, E-mail:
Document Title: Analysis Fee Receipt

ANALYSIS FEE RECEIPT

Receipt No: _______________ Dated: _______________

Received with thanks from _______________________________________________________

_____________________________________________________________________________

Sum of Rs. __________________________ (In words) ________________________________

by Cash/Cheque/Draft No: _______________________________________________________

on account of: _________________________________________________________________

Tentative Report Date: ______________ Sample Received by:__________________

__________________________________
In charge Sample processing Lab

Page 42 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

APPENDIX-2

Soil & Water Testing Laboratory for Research,

Lab ID:
Ph & Fax #, E-mail:
Document Title: Analysis Request Form
Agriculture Department, Government of the Punjab

Sr. No. Description

1. Name of the Farmer
2. CNIC # (Optional)
3. Telephone No. (If available)
4. E-mail (If available)
5. Address: Village,
6. UC
7. Tehsil & District
8. Longitude (If available)
9. Latitude (If available)
10. Square/ Killa No/ Any other.
11. No of samples
12. Depth of soil sample
13. Crops Harvested/ Crops Planned:
14. Fees received Rs.________,16%GST: ______ Total: ______
15. Receipt Date:
16. Tentative Report Date:
ANALYSIS REQUIREMENT:
SOIL WATER FERTILIZER PLANT
No of Samples: No of Samples: No of Samples: No of Samples:
PARAMETERS PARAMETERS PARAMETERS PARAMETERS
Soil Texture Electrical Conductivity Nitrogen Nitrogen
Electrical Conductivity Calcium and Magnesium Phosphorus Phosphorus
Soil Reaction pH Sodium and Potassium Potassium Potassium
Organic Matter Carbonates & Boron
Extractable Phosphorus Bicarbonates Gypsum
Micronutrients
Extractable Potassium Chlorides Micronutrients
Micronutrients SAR and RSC
Extractable boron Other: Other: Other
Other: Depth of Bore ____
Additional Information/Requirement/Purpose: _______________________________________________
Signatures of Farmer /Representative: ___________ Date: ________
Signatures: (In charge Sample Receipt):_____________

Page 43 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

(Appendix-3)
SOIL AND WATER TESTING LABORATORY FOR RESEARCH
QSP/QF/L4/055 Order Sheet for Fertilizer Analysis Issue on 18.01.2021 Revision 3.4

ORDER SHEET FOR FERTILIZER ANALYSIS/ SAMPLES DELIVERY SHEET

Sent by: _______
Date:

Name of Analyst:_______________________________

Analyte (s) /Results Remarks/

Sr Sample(s) N P2O5 K2O Zn Cu Fe Mn B O.M CEC Physical
No Code (%) (%) (%) (%) (%) (%) (%) (%) (%) (meq/100g) Others Conditions

Received by: __________

Date: ________________ Supervised, checked & verified
Counter Signature
Analyzed by: from sources of verification
Agri. Chemist/Chief Scientist
Agricultural Officer/ Assistant Agricultural Chemist/
Soil and Water Testing lab for Research
Soil and Water Testing lab for Research Soil and Water Testing lab for Research
Date: _________________
___________________ Date:___________________

Page 44 of 45
 SOIL FERTILITY RESEARCH INSTITUTE PUNJAB, LAHORE
AGRICULTURE DEPARTMENT, GOVERNMENT OF THE PUNJAB
Thokar Niaz Baig, Lahore. Email: director_sfri@yahoo.com
SFRI-Guide-2021 Standard Test Methods Issue on 05.04.2021 Revision 0

QSP/QF/L4/045 Fertilizer Analysis Report Issue on 01.08.2018 Revision 2.0

No: Date:
FERTILIZER ANALYSIS REPORT

1. Sample reference: Vide No. dated ………..

2. Name and Composition of the Fertilizer
3. Sample receiving date
4. Sample drawn from:
5. Name and address of company
manufacture:
6. Batch No:
7. Physical status of the sample: Type of Colour Texture Dry/
Fertilizer Moist

8. ANALYSIS DETAIL

Lab. No. Nutrient Company claim (%) Results (%) Remarks

9. Method applied:

Note

i. This test was carried out at Temperature 25±50 C and Humidity 30 to 75 %

ii. The analysis is good for the sample supplied at a confidence level of 95%; i.e., k=2 and pertaining to
analyzed sample only.
iii. This test report cannot be reproduced except in full, without written approval of competent authority.
iv. The uncertainty of these parameters has been calculated by laboratory and will be reported on demand.
v. Decision rule: The 5% of claim value, including measurement uncertainty, will be considered as tolerance
limit. The sample will be declared as “unfit” if the sum of test results and tolerance limit is less than the
claim value.

Analyzed by --------------------------------------Agri. Officer (Lab.)/

Checked by ------------------------------------- Assistant Agri. Chemist/

Agricultural Chemist/ Chief or Principal Scientist

Soil and Water Testing laboratory for Research

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