ISO 19670:2017

Overview

ISO 19670:2017 - Fertilizers and soil conditioners - Solid urea aldehyde slow release fertilizer - General requirements - defines the international baseline for pure solid urea‑aldehyde slow‑release fertilizers (for example urea formaldehyde (UF), methylene urea (MU), crotonylidene diurea (CDU) and isobutylidene diurea (IBDU)). The standard sets out general requirements, required analytical methods, sampling and test‑sample preparation, marking and labelling, and packaging, transport and storage provisions for these products. Mixtures of nitrogenous fertilizers that include urea‑aldehyde products are excluded.

Key topics and technical requirements

• Product scope and appearance: Applies to non‑coated, chemically synthesized solid forms (powder, granules, prills, pellets, pastilles, chips). Visual inspection for contaminants is required.
• Compositional requirements (selected minimums/limits shown in the standard):
  • For UF / MU: Total nitrogen (TN) ≥ 36 %, ureic nitrogen ≤ 5 %, activity index (AI) ≥ 40 %, and specified minimum hot‑water soluble nitrogen (HWSN) relative to declared total nitrogen (see standard tables).
  • For IBDU / CDU: Total nitrogen ≥ 28 %, ureic nitrogen ≤ 3 %, nitrogen from IBDU or CDU ≥ 25 %.
• Key analytical parameters and definitions:
  • CWIN (cold water insoluble nitrogen), CWSN, HWIN (hot water insoluble nitrogen), HWSN and AI (Activity Index) - defined and used to quantify slow‑release behaviour.
  • Test procedures include extraction/filtration methods (CWIN at 25 °C, HWIN at 100 °C) and established laboratory determinations for nitrogen fractions.
• Analytical methods referenced: Total nitrogen by ISO 5315, ureic nitrogen by ISO 19746, HPLC methods for urea condensates in ISO 25705, plus detailed CWIN/HWIN procedures in the document.
• Sampling and handling: Methods for bags and bulk products, sample reduction and preparation for testing are specified to ensure representative laboratory samples.
• Marking, labelling, packaging, transport and storage: Requirements to support safe handling and correct declaration for international trade.

Applications and users

ISO 19670:2017 is intended for:

• Fertilizer manufacturers and R&D teams for product specification, production control and QC.
• Analytical laboratories performing conformity testing and activity/solubility profiling (CWIN, HWIN, AI).
• Regulatory bodies, certification and conformity assessment organizations verifying labeling and declared contents.
• Traders, importers and agronomists specifying slow‑release nitrogen fertilizers for agronomic planning and supply chain compliance.

Related standards

• ISO 5315 - Total nitrogen (titrimetric after distillation)
• ISO 19746 - Urea content / ureic nitrogen (HPLC)
• ISO 25705 - Determination of urea condensates (HPLC)
• ISO 7409 / ISO 7410 / ISO 7742 / ISO 8633 - marking, final sampling, sample reduction and simple sampling methods

Keywords: ISO 19670:2017, urea aldehyde slow release fertilizer, urea formaldehyde, methylene urea, CDU, IBDU, CWIN, HWIN, activity index, fertilizer standards, analytical methods, fertilizer labelling.