ISO 18645:2016

INTERNATIONAL ISO
STANDARD 18645
First edition
2016-03-15
Fertilizers and soil conditioners —
Water soluble fertilizer — General
requirements
Matières fertilisantes — Engrais soluble dans l’eau — Exigences
générales
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Requirement . 2
4 Test method . 3
4.1 Visual inspection for foreign matter . 3
4.2 Determination of nitrogen, phosphorus and potassium contents . 3
4.3 Determination of calcium, magnesium and sulphur contents . 3
4.4 Determination of molybdenum, boron and manganese, zinc, copper and iron contents. 4
4.5 Determination of the chelated fraction of micro-nutrients . 4
4.6 Determination of the mass fraction of water insoluble matter . 4
4.6.1 Principle . 4
4.6.2 Reagents and materials . 4
4.6.3 Apparatus . 4
4.6.4 Ambient temperature controlled at (20 ± 10) °C . . 4
4.6.5 Test procedure . 4
4.6.6 Calculation of the test result . 5
4.6.7 Tolerance . 5
4.7 Determination of the pH value . 5
4.8 Determination of arsenic, cadmium, lead, chromium and mercury contents . 5
4.9 Determination of biuret content . 5
4.10 Determination of mass fraction of chloride . 5
5 Sampling and preparation of test sample . 5
5.1 Sampling method . 5
5.1.1 Products in bags . 5
5.1.2 Products in bulk . . . 5
5.2 Reduction of samples . 6
5.3 Test sample preparation . 6
6 Marking and labelling . 6
7 Package, transport and storage . 7
Bibliography . 8
Foreword
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The committee responsible for this document is ISO/TC 134, Fertilizers and soil conditioners.
iv © ISO 2016 – All rights reserved

INTERNATIONAL STANDARD ISO 18645:2016(E)
Fertilizers and soil conditioners — Water soluble fertilizer
— General requirements
1 Scope
This International Standard specifies the requirements for testing methods, sampling and preparation
of test sample, marking and labelling, as well as package, transport, and storage of water soluble
fertilizers.
This International Standard is applicable to water soluble fertilizers which are completely soluble in
water and are suitable for fertigation and sprinkling irrigation, as well as for foliar application (foliar
feeding).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5315, Fertilizers — Determination of total nitrogen content — Titrimetric method after distillation
ISO 6353-1:1982, Reagents for chemical analysis — Part 1: General test methods
ISO 6598, Fertilizers — Determination of phosphorus content — Quinoline phosphomolybdate
gravimetric method
ISO 7409, Fertilizers — Marking — Presentation and declarations
ISO 7410, Fertilizers and soil conditioners — Final samples — Practical arrangements
ISO 7742:1988, Solid fertilizers — Reduction of samples
ISO 8633, Solid fertilizers — Simple sampling method for small lots
ISO 17318, Fertilizers and soil conditioners — Determination of arsenic, cadmium, chromium, lead and
mercury contents
ISO 17319, Fertilizers and soil conditioners — Determination of water-soluble potassium content —
Potassium tetraphenylborate gravimetric method
ISO 18643, Fertilizers and soil conditioners — Determination of biuret content of urea-based fertilizers —
HPLC method
EN 16195, Fertilizers — Determination of chlorides in the absence of organic material
CEN/TS 16196, Fertilizers — Manganimetric determination of extracted calcium following precipitation in
the form of oxalate
EN 16198, Fertilizers — Determination of magnesium by complexometry
EN 13366, Fertilizers — Treatment with a cation exchange resin for the determination of the chelated
micro-nutrient content and of the chelated fraction of micro-nutrients
EN 13368-1, Fertilizers — Determination of chelating agents in fertilizers by chromatography —Part 1:
Determination of EDTA, HEEDTA and DTPA by ion chromatography
EN 13368-2, Fertilizers — Determination of chelating agents in fertilizers by chromatography — Part 2:
Determination of Fe chelated by o,o-EDDHA and o,o-EDDHMA by ion pair chromatography
EN 15451, Fertilizers — Determination of chelating agents —. Determination of iron chelated by EDDHSA
by ion pair chromatography
EN 15452, Fertilizers — Determination of chelating agents — Determination of iron chelated by o,p-
EDDHA by reversed phase HPLC
EN 15749, Fertilizers — Determination of sulfates content using three different methods
EN 15950, Fertilizers — Determination of N-(1,2-dicarboxyethyl)-D,L-aspartic acid (Iminodisuccinic acid,
IDHA) using high-performance liquid chromatography (HPLC)
EN 15961, Fertilizers — Extraction of water-soluble calcium, magnesium, sodium and sulfur in the form of
sulfates
EN 15962, Fertilizers — Determination of the complexed micro-nutrient content and of the complexed
fraction of micro-nutrients
EN 16109, Fertilizers — Determination Of complexed micro-nutrient ions in fertilizers — Identification of
lignosulfonates
EN 16847, Fertilizers — Determination of complexing agents in fertilizers — Identification of heptagluconic
acid by chromatography
EC Regulation No. 2003/2003
3 Requirement
3.1 Appearance: the product (including single fertilizers, complexed micronutrients, and/or products
obtained chemically) is a mixture of powders, prills, and/or granules free of foreign matter.
3.2 Water soluble fertilizer products shall be tested to demonstrate the conformance with the
requirements specified in Ta
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