KENYA STANDARD               KS 46: 201 8 
                     
 
  
 
 
 
 
 
 
 
 
Granulated s uperphosphate 
fertilizer - Specification  
 
 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
  
 
 
 
 
 
 
 
 
 
     DRAFT STANDARD   AUGUST  2018                                          Fourth   edition                                                                                   
 
 
 
                                                                                                                             
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TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Kenya Agriculture and livestock research Organization (KALRO)  
Government chemist  
Mea Ltd.  
Kel Chemicals Ltd.   
Amiran (K) ltd  
Chemagro Ltd.  
Yara East Africa  
Kenya Tea  Development Agency.  
Kenya Plant Health Inspectorate Services (KEPHIS)  
Ministry of Agriculture, livestock and fisheries  
Osho Chemicals  
Elgon chemicals  
Toyota   Tshusho Fertilizers Africa  
University of Nairobi -Department of plant science and crop protection  
OCP Africa  
Kenya Bureau of Standards — Secretariat  
 
  
 
 
 
 
  
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Stan dards shall be regularly reviewed. Suggestions for 
improvements to published standards, addressed to the Managing   Director, Kenya Bureau of Standards, are  
welcome.  
 
 
 
 
 
© Kenya Bureau of Standards, 201 8 
 
Copyright.  Users are   reminded that by virtue o f section 6 of the Copyright Act, Cap. 130 of the Laws of Kenya, copyright subsists in all 
Kenya Standards and except as provided under section 7 of this Act, no Kenya Standard produced by Kenya Bureau of Standards m ay be 
reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from the Managing 
Director.  ©KEBS                                                                                                                                                                                          KS 46: 2018                                                                                                                                                  
   3  
Permission may be conditional on an appropriate royalty payment.  
 
Care should be taken to ensure that material used is from the current edition of the standard and that it is updated whenever the standard is 
amended or revised.  The number and date of the standard should therefore be clearly identified.  
 
The use of material in print or in electronic form to be used commercially with or without pay ment or in commercial contracts is subject to 
payment of a royalty.  
 
 
 
 
 
 
 
 
KENYA STANDARD                   KS 46: 201 8 
                       
 
  
 
Granulated superphosphate 
fertilizers - Specification  
 
 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
                                                                                                                             
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                                        KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+254 020) 605490, 602350, Fax: (+254 020) 604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region     Lake Region          Rift Valley Region  
P.O. Box 99376, Mombasa -80100   P.O. Box 2949, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254 041) 229563, 230939/40                Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254 041) 229448    Fax: (+254 057) 21814  
 
 
 
Foreword  
 
The Fourth  edition  of this Kenya Standard was prepared by the Technical Committee 
on Fertilizers  and soil conditioners  under the g uidance of the Standards  Projects 
Committee and it is in accordance with the procedures of the  Kenya Bureau  of 
Stand ards.  
 
 
Heavy metal contamination limits for As, Cd, Hg, Se, Pb and Cr have also been 
specified, as is the case with other fertilizer products, due to the environment aspect 
associated with rock -phosphate.  
 
The particle size has been harmonized and AOAC me thods of analysis have been 
adopted in the revision.  
 
During the revision of this standard , reference  was made to the following documents:  
 
     FAO Mineral fertilizer Specifications , 2012  
         EU Limits on cadmium , 2018  
 
The assistance derived from th e above sources is hereby acknowledged with thanks.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ©KEBS                                                                                                                                                                                          KS 46: 2018                                                                                                                                                  
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KENYA STANDARD  
Granulated superphosphate fertilizers - Specification  
 
 
 
 
1.  SCOPE  
 
            This Kenya Standar d specifies requirements, sampling method and test 
methods for granulated superphosphate fertilizers.  
 
   
2. DEFINITIONS  
  
 For the purposes of this standard the following definitions  in addition to 
those contained in KS ISO 8157 shall apply:  
 
2.1 superph osphate — The product  obtained by treating phosphate rock with 
sulphuric acid.  It is also known as single superphosphate.   
 
2.2 concentrated  superphosphate —
 The product obtained by treating 
phosphate rock with phosphoric acid or phosphoric acid and sulp huric acid.  
It is also c alled ‘enriched superphosphate’ or  ‘triple superphosp hate’.  
 
2.3 Available  phosphorus — The fraction of phosphorus available to plants.  This 
is the sum of the water -soluble and citrate -soluble phosphorus.  
 
2.4 total phosphorus   —    The sum of available  and citrate -insoluble 
phosphorus.  
3 Requirements  
 
3.1 Description   
 
The fertilizer shall be homogenous and free -flowing, in the form of granules  or   
prills                                                                                                                              
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     3.2. General requirements  
a) The fertilizer shall be free from foreign matter  
b) It shall be free from dust and lumps  
c) Not less than 90% of the material shall pass through 4 mm IS sieve and be 
retained on 1 mm IS sieve. Not more than 5% shall be below 1 mm size  
 
 
 
 
TABLE 1.  REQUIREMENTS FOR SUPERPHOSPHATES  
 
 
  Sl   
  No                                                                                                                          
 
CHARACTERISTI
CS  
REQUIREMENTS, PER CENT, BY MASS   
METHODS 
OF TEST   
Grade 1 
Single 
Superphosph
ate  
Grade 2 
Single 
Superphosph
ate  
TRIPLE  
Superphosph
ate 
(i) Water -soluble 
phosphate  
(as P 2O5), min   
 
          18.0   
  
        14.5  
 
   40  AOAC  
(ii) Available 
phosphate  
(as P 2O5),min  
       21.5   
      16.5  
   46.0  AOAC  
(iii) Free phosphoric 
acid  
(as P 2O5), Max  
         4.0  
       4.0   
    4.0  AOAC  
(iv) Moisture , max          5.0         5.0     4.0  AOAC  
 
 
 
 
 
3.4.    Heavy metal contaminants   
 
The heavy metal contaminants, if present, shall not exceed the limits stipulated in 
Table 2.  
 
 
 
Table 2 — Heavy metal contaminants limits  
 
SL NO  Parameter  Limits in 
ppm Test method  
i) Arsenic, As, max.  20.0 AOAC  
ii) Cadmium, Cd, max.  15.0 AOAC  ©KEBS                                                                                                                                                                                          KS 46: 2018                                                                                                                                                  
   7 iii) Mercury, Hg, max.  0.1 AOAC  
iv) Selenium, Se, max.  1.0 AOAC  
v) Lead, Pb, max.  30.0 AOAC  
 
 
   
 
4. PACKAGING AND MARKING  
 
4.1 Packaging — The material shall be packaged in suitable containers and 
quantities.   
 
 
3.1.1The fertilizer shall be packaged in materials that ensure the product integrity 
and quality and protect it against physical damage, chemical and moisture 
contamination.  
 
3.1.2. The  fill of the package shall comply with the weight and measures act CAP 513 
of the laws of Kenya  
 
3.1.3 The disposal of used package and condemned fertilizer shall comply with EMCA 
1999 no.8 of the disposal of solids and liquid wastes  
 
4.2 Marking  — The fol lowing information shall be marked on each packaging 
container:  
 
4.2.1  Name and address of the manufacturer/packer / importer.  
 
4.2.2  Name of the product.  
 
4.2.3  Grade of single superphosphate or concentrated superphosphate.  
 
4.2.4  The minimum water -soluble phosp hates stated as P 205 content of the 
material.  
 
4.2.5  The net weight of the material in the package.  
 
4.2.6  The content of fluorine and sulphur.  
 
4.2.7  Handling instructions.  
 
4.3 A certificate of analysis shall accompany each consignment.  
 
5. SAMPLING  
This shall be done ac cording to ISO standard s ISO 863 3 and 8634 - Fertilizers -
Sampling.