ISO/TC 134 - Fertilizers, soil conditioners and beneficial substances

This document establishes a system of classification for fertilizers, soil conditioners and beneficial substances. The system of classification is in accordance with: — the nutrient contents of the fertilizer; — the effect of the fertilizer; — the type of product; and — the acidity and alkalinity of the product as a supplement. It is applicable to fertilizers, soil conditioners and beneficial substances. The classification scheme for fertilizers, soil conditioners and beneficial substances (in accordance with nutrient contents) is shown in Annex A.

This document specifies general requirements for the testing, sampling and preparation of test samples and the marking, labelling, packaging, transport and storage of compound fertilizers. This document is applicable to inorganic solid compound fertilizers. This document is not applicable to controlled-release compound fertilizers.

This document specifies a method for the determination of total nitrogen content in all nitrogen containing fertilizers by combustion method. NOTE 1 The presence of non-nutritive sources of nitrogen (e.g. chelating agents) causes positive bias to samples being analysed for nutritive nitrogen content. The non-nutritive nitrogen content is subtracted from the total nitrogen value to determine the nutritive nitrogen content. NOTE 2 Common internationally traded fertilizers were evaluated for total nitrogen by combustion analysis in the ring-study in this document. While the fertilizers analysed in this international ring study were mineral fertilizers, previous studies have shown that total nitrogen by combustion is suitable for use with many non-mineral, nitrogen-containing fertilizers.

This document specifies the method for the determination of the EDTA soluble phosphorus content of inorganic fertilizers. The method is applicable for fertilizers composed of or blended from multiple sources such as superphosphate, ammonium phosphate, triple superphosphate, and/or nitrophosphate. It is not suitable for fertilizers containing calcium magnesium phosphates.

This document establishes an overview of the relevant methods for the determination of calcium and magnesium as defined in ISO 8157. This document is applicable to any mineral soil amendment, neutral, basic or acid containing calcium and/or magnesium.

This document specifies a method to measure the total sulfur content in fertilizer and soil conditioner materials. This method is applicable for measuring total sulfur concentration in solid and liquid fertilizers and its raw inputs in the range of 0,1 % to 97 %.

This document is applicable to the sampling of mineral fertilizers and liming materials supplied or ready for supply to third parties, as a lot or in smaller lots, where such supply or readiness for supply is subject to legal requirements. This document specifies plans and methods of sampling of a lot of solid fertilizer or liming material, if sampling in motion is not possible, to obtain samples from bulk static heaps in order to ascertain compliance with legal requirements, in particular in relation to the accuracy of compulsory or permitted statutory declarations. The methods specified in this document are not applicable to obtain samples for physical size analysis or for chemical analysis which may be altered by particle granulometric segregation. This document is applicable to single nutrient fertilizers, to uniform complex fertilizers and to milled or granulated fertilizers and liming materials. The methods described in this document are not suitable for sampling other types of fertilizer, for example blended fertilizers. NOTE The term 'fertilizer' is used throughout the body of this document and includes liming materials unless otherwise indicated.

This document establishes a method for the determination of monosilicic acid concentrations in nonliquid fertilizer materials. Monosilicic acid is reported as silicon (Si). This extraction method is applicable to the detection of monosilicic acid in nonliquid fertilizer products, blended products, and beneficial substances at silicon (Si) concentrations of 2 to 84 g/kg, with a limit of detection (LOD) of 0,6 g/kg Si, and a limit of quantification (LOQ) of 2 g/kg correlating well with plant uptake. This method is not applicable to liquid silicon fertilizer sources due to an expected low bias of Si recovery and low correlation with plant uptake.

This document specifies the test procedure for the determination of the salt out temperature (SOT), also known as the crystallization temperature (CT) of liquid (fluid) fertilizers, using an inexpensive and simple technique. This method might not be applicable to the binary and ternary fertilizers, especially with regards to the last crystal to disappear (LCTD). Some of these exceptions are discussed in the procedure (Clause 8).

This document specifies two methods for the determination of the neutralizing value (NV) of liming materials. Method A is applicable to all liming materials except silicate liming materials. NOTE 1 Examples of hard liming materials are limestone and dolomite. Examples of soft liming materials are chalk, marl and burnt lime. Method B is applicable to all liming materials. Neither method correctly takes into account the potential neutralizing value of material containing more than 3 % P2O5. For a more accurate agronomic assessment of products containing more than 3 % P2O5, EN 14984[8] is used to determine the liming efficiency. NOTE 2 The methods described in ISO 6598 and ISO 7497 can be used for the determination of P2O5 content. Further information on P analyses is given in References [5] and [6]. NOTE 3 Carbonate consumes H+ and removes acidity in solution with subsequent dissociation to H2O and CO2. Forms of orthophosphate can consume H+ but are not dissociated to molecular forms that remove acidity. The acidity is back titrated with alkali causing an underestimation of NV.

This document specifies a method for the extraction of water soluble phosphorus. The method is applicable to all fertilizers, including compound fertilizers, where water soluble phosphorus is to be determined.

This document specifies two methods for the determination of the particle size distribution of liming materials. Method A (the dry sieving method) is applicable to all liming materials except wet and paste-like products. Method A is not applicable if blinding, caking, electrostatic charges or agglomeration occur after drying. Method B (the wet sieving method) is applicable to products which are susceptible to blinding, caking, electrostatic charges or agglomeration after drying. Method B can be used to determine the primary particle size distribution of granulated products. Method B is not applicable to burnt lime and liming materials containing water-soluble constituents.

This document specifies a method for determining the reactivity of calcium carbonate and calcium magnesium carbonate liming materials. It assesses the speed and effectiveness of their neutralising potential by automatic titration with citric acid. This method is applicable only to liming materials with a maximum particle size of 6,3 mm determined in accordance with ISO 20977. NOTE For marble dolomite (BET procedure as defined in ISO 9277 below 500 m2/kg), see EN 14984.

This document specifies the procedure for the analysis of humic acids and hydrophobic fulvic acids which is applicable to dry and liquid materials used as ingredients in commercial fertilizers, soil amendments, and geological deposits.

ISO 7409:2018 specifies the procedure for marking containers or labels for fertilizers. ISO 7409:2018 is applicable to all fertilizers in containers or bulk.

ISO 21263:2017 specifies a method for the determination of the slow release properties of nutrients from coated fertilizers. pH-dependent hydrolysis and degradation by biological or microbial mechanisms are excluded. The specified method is only applicable to products releasing any nutrients by means of a non-biological process (i.e. those where the nutrients are released by a physical mechanism). Microbial attack on the coating (e.g. sulfur coated fertilizers) and the consequences thereof are not measurable by the technique described. This method involves a lengthy process which may not be appropriate for day to day testing purposes. Accelerated methods can be used provided they are correlated with this document. An example of such an accelerated method is described in Annex B. Regression analysis can also be used for this purpose.

ISO 20702:2017 specifies the ion chromatography method for the determination of microamounts of water soluble inorganic anions, such as fluoride (F−), chloride (Cl−), bromide (Br−), iodide (I−), nitrite (NO2−) and thiocyanate (SCN−), in fertilizers.

ISO 19670:2017 specifies general requirements, analytical methods, sampling and preparation of test sample, marking and labelling, packaging, transport and storage for solid urea aldehyde slow release fertilizer. ISO 19670:2017 applies to pure solid urea aldehyde slow release fertilizer, i.e. urea formaldehyde (UF), methylene urea (MU), crotonylidene diurea (CDU), isobutylidene diurea (IBDU). This document does not apply to mixtures of nitrogenous fertilizers containing solid urea aldehyde slow release fertilizer.

ISO 19746:2017 specifies the test procedure for determining the urea content in urea-based fertilizers, including urea, urea aldehydes [methylene urea fertilizers, isobutylene diurea (IBDU), crotonylidene diurea (CDU)], urea triazone fertilizers, urea ammonium nitrate (UAN), sulfur- and polymer-coated urea (SCU and PCU), as well as compound fertilizers containing urea. The method is based on High Performance Liquid Chromatography (HPLC). The proposed method is an extension of the AOAC Official Method 2003.14 which was collaboratively studied for the "Determination of Urea in Water-Soluble Urea-Formaldehyde Fertilizer Products and in Aqueous Urea Solutions" in 2003. The method was published in the Journal of AOAC in 2004[4] and was granted the First Action in 2003 and the Final Action in 2008. This method also applies to the determination of biuret content in urea containing fertilizer with the results published in the J. AOAC in 2014[5]. This method was adopted by the International Organization for Standardization (ISO) as a Committee Draft (ISO/CD 18643) in 2014, and after review and the Ring Test Analyses[6].

ISO 15959:2016 specifies a method for the determination of phosphorus in fertilizer extracts. The method is applicable to all extracts of fertilizers for the determination of the different forms of phosphorus as phosphorus soluble in mineral acids, water soluble phosphorus, phosphorus soluble in solutions of ammonium citrate, phosphorus soluble in 2 % citric acid and phosphorus soluble in 2 % formic acid.

ISO 18642:2016 specifies the general requirements regarding testing methods, sampling and preparation of test sample, marking and labelling, package, transport, and storage of fertilizer grade urea. It is applicable to urea in solid form, e.g. granular, prilled, or pastilled, which is made by the reaction of ammonia with carbon dioxide. Urea can be classified by its intended use, industrial and/or agricultural. It is mainly used as fertilizer in the field of agriculture. It is only applicable to fertilizer grade urea in the field of agriculture.

ISO 14820-2:2016 specifies methods for the reduction and preparation of samples of fertilizers and liming materials and sets out the requirements for sample preparation reports. It also specifies methods for the preparation of test samples and test portions from laboratory samples of fertilizer for subsequent chemical or physical analysis. It does not cover the preparation of samples for certain physical tests which require test portions of more than 2 kg. It is applicable to all fertilizers. NOTE The term "fertilizer" is used throughout the body of this part of ISO 14820 and is taken to include liming materials unless otherwise indicated.

ISO 15604:2016 specifies a method for the determination of any one form of nitrogen in the presence of any other form. The method is applicable to any fertilizer provided for in the Regulation (EC) No 2003/2003, Annex I[2] containing nitrogen in various forms.

ISO 14820-1:2016 specifies sampling plans and methods of representative sampling of fertilizers and liming materials to obtain samples for physical and chemical analysis, from packages and containers up to and including 1 000 kg, from fluid products and from fertilizers in bulk provided the product is in motion. It is applicable to the sampling of lots of fertilizer or liming material supplied or ready for supply to third parties, as such, or in smaller lots, each of which would be subject to local, national or regional legislation. Where legislation so requires, samples are taken in accordance with this part of ISO 14820. NOTE The term "fertilizer" is used throughout the body of this document and is taken to include liming materials unless otherwise indicated. This part of ISO 14820 does not cover complete, statistical sampling plans.

ISO 18644:2016 specifies the requirements for testing methods, sampling and preparation of test sample, marking and labelling, as well as package, transport, and storage of controlled-release fertilizer. ISO 18644:2016 is applicable to controlled-release products having one or more primary fertilizer nutrient (nitrogen and/or phosphorous and/or potassium) in a controlled-release form. They can be made by bulk blending (BB) fertilizers or by special processes.

ISO 25475:2016 specifies a method for the determination of the ammoniacal nitrogen content in fertilizers. The method is applicable to all nitrogenous fertilizers including compound fertilizers, in which nitrogen is found exclusively either in the form of ammonium salts or ammonium salts together with nitrates. ISO 25475:2016 is not applicable to fertilizers containing urea, cyanamide or other organic nitrogenous compounds.

ISO 25705:2016 specifies methods for the determination of isobutylidene diurea (IBDU), Crotonylidene diurea (CDU) (method A) and methylene-urea oligomers (MU) (method B) in fertilizers using high-performance liquid chromatography (HPLC). The method is applicable to all fertilizers which do not contain interfering organic compounds.

ISO 18643:2016 specifies the test procedure for determination of the biuret content in liquid and solid urea-based fertilizers based on the HPLC method.

ISO 18645:2016 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. ISO 18645:2016 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).

ISO 17318:2015 specifies the test methods for determination of metals soluble in nitric acid: arsenic, cadmium, chromium, lead, and mercury contents in fertilizers. ISO 17318:2015 is applicable to the analysis of arsenic, cadmium, chromium, lead, and mercury contents in fertilizers. Special attention should be given when analysing some micro-nutrients fertilizers.

ISO 17323:2015 specifies general requirements, sampling and preparation of test sample, marking and labelling, packaging, transport, and storage for SCU.

ISO 17322:2015 specifies analytical methods for the determination of mass fraction of total nitrogen, one-day dissolution rate (1DDR), seven-day dissolution rate (7DDR), mass fraction of sulfur, mass fraction of biuret, mass fraction of water (H2O), and particle size of SCU. These methods are applicable to SCU.

ISO 17319:2015 specifies a gravimetric method for the determination of the water-soluble potassium content of test solutions of fertilizers. It is suitable for use in arbitration and for reference purposes. ISO 17319:2015 is applicable to those fertilizers containing more than 1,0 % K2O or equivalent amount of K content.

Describes a procedure for the de-aeration of suspension samples for physical testing. It is not suitable if the sample contains more than a trace of free ammonia, or if the sample is too viscous.

Specifies a procedure for preliminary examination of a single sample as received and a procedure for preparing a test sample by blending and reduction of a series of samples representative of a consignment of fluid fertilizer.

The method is applicable to solid, but not powder fertilizers, dry only. It is not suitable for fertilizers which contain a large proportion of particles exceeding 5 mm in diameter. Its principle is pouring the fertilizer from a specified funnel into a specified measuring cylinder of known volume and weighing the contents of the cylinder. If the fertilizer has absorbed moisture during transport or storage, it is necessary to dry it in an environmental chamber.

Specifies two methods for dry fertilizers only: the machine-tapping method and the hand-tapping method. Its principle is pouring the fertilizer from a specified funnel into a specified measuring cylinder of known volume, tapping the cylinder by means of a tapping machine or the walls of the cylinder by hand, and weighing the contents of the cylinder. If the fertilizer has absorbed moisture during transport or storage, it is necessary to dry it in an environmental chamber.

The method is applicable to fertilizers, dry only, which contain a large proportion of particles of diameters less than 0,5 mm. Its principle is pouring the fertilizer from a specified filling device into a specified measuring cylinder of known volume and weighing the contents of the cylinder. If the fertilizer has absorbed moisture during transport or storage, it is necessary to dry it in an environmental chamber.

Gives the mathematical derivation of the sampling plan specified in ISO 8634. The tables of values in the annexes A and B are for information only.

Specifies a method for sampling a delivery of more than 250 t of fertilizer and, after analysis of the sample(s), presents rules for assessing the quality. Annex A forms an integral part of this standard. Annex B is for information only.

Applies to all solid fertilizers. Specifies methods for the preparation of test samples and test portions from laboratory samples. Figure 1 shows a schematic diagram of the sampling process.

The method is suitable for free flowing materials for measuring angles greater than 20 , but not for those which contain a large proportion of particles exceeding 5 mm in diameter.It consists in measuring of the height and diameter of the base of the cone, obtained by allowing a sample to fall through a fixed distance from a defined funnel onto a horizontal baseplate.

The method consists in passaging of the material through a rotating sample divider and collecting of the fractions, followed by rejection or recombination of some of the fractions. By choosing suitable equipment it is applicable to any mass above a minimum defined by size and number of particles.

Specifies a method for the determination of a particle size distribution, consisting in mechanical dry sieving of a sample with one or more test sieves.The second edition cancels and replaces the first edition (1986), clause 10 of which has been amended.

The report specifies the extent of mass reduction beyond which the error in the representativity can no longer be ignored.

The result of the method is a measure for the porosity of the material. The method is applicable to substances which do not contain materials soluble in gas oil and which are prilled or granular. It consists in total immersing of a test portion in gas oil for a specified period, followed by the draining away and the removal of surplus gas oil under specified conditions, and measuring of the increase in mass of the test portion.

The method consists in precipitating, after hydrolysis if necessary, of orthophosphate ions in the form of quinoline phosphomolybdate, in an acid medium and in the presence of acetone, at approximately 75 °C, followed by filtrating, washing drying and weighing of the precipitate obtained.