KENYA STANDARD        KS 158: 20 18  
         
 
 
 
 
 
 
 
 
 
 
 
  
Solid compound fertilizer  — Specification  
 
 
 
 
 
 
 
 
        
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   DRAFT STANDARD   AUGUST   2018 
 
 
© KEBS 201 8        Fifth   Edition  2018KS 158: 201 8 
ii  © KEBS 201 8 — All rights reserved   
TECHNICAL COMMITTEE  REPRESENTATION  
 
The fo llowing organizations were represented on the Technical Committee:  
 
Government Chemist  
Mea Ltd.  
Chemagro Ltd  
Kenya Plant Health Inspectorate Services (KEPHIS)  
Kenya Agricultural   and livestock research organization  
Yara East Africa Ltd  
Kenya Tea Developm ent A gency  
University of Nairobi  
Ministry of Agriculture , Livestock and fisheries  
Amiran (K) Ltd  
Toyota Tshusho Fertilizers  
Elgon chemicals  
Osho chemicals  
OCP Kenya Ltd.  
Kel Chemicals  
Kenya Bureau of Standards — Secretariat  
 
 
 
 
 
 
REVISION OF KENYA STANDARD S 
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
 
© Kenya Bureau of standa rds, 201 8 
 
Copyright:  Users are reminded that by virtue of 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 may be reproduced, st ored in a retrieval 
system in any form or transmitted by any means without prior permission in writing from the Managing Director.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
© KEBS 201 2 — All rights reserved   iii  
 
 
 
 
 
KENYA STANDARD            KS 158: 2018 
          ICS 65.080  
 
 
 
 
 
 
 
 
 
 
 
 
Solid compound fertilizer  — Speci fication  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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  KS 158: 201 8 
iv  © KEBS 201 8 — All rights reserved  Fax: (+254 041) 229448    Fax: (+254 057) 21814  
 
 
 
 
Foreword  
 
This F ifth  edition  of KS 158 was prepared by the Technical Committe e on 
Fertilizers and soil conditioners under the Standards  projects Committee and it is 
in accordance with the procedures of the  Kenya Bureau of Standards . 
 
During the revision of this standard, special attention was paid to the 
environmental aspect associated with fertilizer raw -materials.  Thus setting limits 
for heavy metal contamination of Arsenic (As), Cadmium (Cd), Mercury (Hg), 
Selenium (Se), Lead (P b) and Chromium (Cr). The tolerances for declared  primary 
nutrients have been revised to safeguard the interests of the user.  
 
Recent Association of Official Analytical Chemists (AOAC) methods of analysis were 
adopted  
and limits for primary nutrients guar antee have been set.  
 
During the revision  of this standard, reference was made to the following 
document:  
 
   FAO Minera l fertilizer Specifications 201 2 
   EU Limits on cadmium  
 Indian fertilizers specifications: tolerances for declared primary nutrients  
  
 
Acknowledgement is hereby made for assistance derived from this source.  
 
 
  
© KEBS 201 8 — All rights reserved                                                                                                                  1 KENYA STANDARD            KS 158: 20 18 
 
 
Solid compound fertilizer — Specification  
 
1 Scope  
 
This Kenya Standard specifies the requirements, and prescribes the methods of 
sampl ing and tests for solid compound fertilizers.  
 
2. Normative references  
 
KS ISO 8157 : 2015: Fertilizers Vocabulary  
 
3. Definitions  
For the purpose of this standard the definitions in KS ISO   8157 :2015  shall 
apply  
 
4 Requirements  
 
4.1 Description   
 
The fe rtilizer shall be homogenous and free -flowing, in the form of granules, 
pellets, prills or crystals.  
 
4.2. General  requirements  
Physical  
a) The fertilizer shall be free from foreign matter . It shall be free from dust and   
lumps  
b) Not less than 90% of th e 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  
 
 
 
4.3 Chemical  
  
A compound fertilizer shall contain two or more of the following primary plant 
nutrient elements intended for fertili zing of crops: nitrogen (N), phosphorus (P) 
and potassium (K).  The lower limit of the declared value of any of the primary 
nutrients shall   comply with the tolerances stated in the table  1 below   
 
SL 
NO nutrient content  tolerances  in units  
i  less than 15 0.5 
ii 15 to 21 0 .6 
iii  more than 21  0.7 
 
  
 
2  © KEBS 20 18 — All rights reserved  Besides the primary nutrient elements, the fertilizer may also contain one or more 
of the following elements: Boron, Calcium, Cobalt, Copper, Iron, Magnesium, 
Manganese, Molybdenum, Sulphur and Zinc, whic h, when present for the 
purpose of fertilizing of crops and mentioned in any form or manner, shall be 
guaranteed on the elemental basis.  Sources of the elements guaranteed and 
proof of availability shall be provided upon request.  The elements shall be 
mentioned and guaranteed if their percentage values by mass are equal to or 
more than the values shown in Table 2  
                            Table 2— Minimum percentage for guarantee  
 
SL 
NO Element  % 
i) Boron  (B)  0.02 
ii) Calcium   
(Ca) 1.00 
iii) Cobalt   (Co) 0.0005  
iv) Copper   (Cu) 0.05 
v) Iron (Fe)  0.10 
vi) Magnesium (Mg)  0.60 
vii) Manganese (Mn)  0.050 
viii) Molybdenum 
(Mo) 0.0005  
ix) Sulphur  (S) 1.00 
x) Zinc (Zn)  0.05 
 
4.4 The moisture content shall be not more than 1.5 % m/m.  
 
45  pH Value   
 
The pH value of a 10 % (m/v) aqueous solution, of the fertilizer, shall be not less 
than 4.5, when tested in accordance with  appropriate method (AOAC method for 
pH) 
 
4.6 Heavy metal contaminants   
 
The heavy metal contaminants, if present, shall not exceed the limits stipulated in 
Table 2.  
 
 
 
Table 3 — 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  
iii) Mercury, Hg, max.  0.1 AOAC  
iv) Selenium, Se, max.  1.0 AOAC  KS 158: 20 18 
 
© KE BS 201 8 All rights reserved   3 v) Lead, Pb, max.  30.0 AOAC  
VII Chromium  500     
         AOAC  
 
 
3 Packaging and marking  /labelling  
 
3.1 Packaging   
 
The fertilizer shall be packaged in materials that protect the product from physical, 
chemical and moisture contamination  
 
3.2. Marking  /Labelling  
 
The following information shall be clearly and indelibly marked/labelled on each 
package.          
 
a) Name, address and physical location of manufacturer/packer/importer;  
b) name of the fertilizer, i.e.“Compound Fertilizer”;  
c) guaranteed percentage by m ass of each of the primary plant nutrients 
(NPK);    
d) name and percentage by mass of any other guaranteed element present;  
e) date of manufacture, expiry date and batch/lot number;  
f) the form in which nutrient is present;  
g) the percentage of water -soluble  or availa ble  phosphates;  
h) storage and handling instructions;  
i) the net weight of the fertilizer in the package;  
j) country of origin;  
k) A warning or cautionary statement on the label for any product that 
contains 0.3 % or more of boron in  
a water -soluble form.  This stat ement shall carry the word 'WARNING‟ or 
'CAUTION' conspicuously displayed, shall state the crop(s) for which the 
fertilizer is to be used on and state that the use of the fertilizer on any, other 
than those recommended may result in serious injury to the c rop(s).  
Fertilizers containing 0.001 % or more of molybdenum also require a 
warning statement on the label.  This shall include the word 'WARNING' or 
„CAUTION‟ and the statement that the application of fertilizers containing 
molybdenum may result in folia ge crops containing levels of molybdenum 
which are toxic to ruminant animals.  
 
4 Certificate of analysis  
Each consignment shall be accompanied by a certificate of analysis.  
  
 
4  © KEBS 20 18 — All rights reserved  5 Sampling  
This s hall be done as per ISO standard s ISO 8633 and ISO 8634 -on sampli ng of 
fertilizers .