The Analysis of Fertilizers

There are several publications detailing standard or officially recognized methods of fertilizer analysis. These include Official Methods of Analysis of AOAC International (Horwitz, 2000); Official and Standardised Methods of Analysis, published by the Royal Society of Chemistry (Watson, 1994); and Fertilisers - Methods of Analysis used in OEEC Countries (OEEC, 1952). There are also the EEC methods, which have been implemented in the UK by the Fertilisers (Sampling and Analysis) Regulations 1996 (Statutory Instrument (SI) 1996 No. 1342). The title page of the SI may be downloaded from the following website: with the Schedule 2, Methods of Analysis at: si1996/Uksi_19961342_en_4.htm#sdiv2 Note: By changing the year and number of the SI using the above URL format, it is possible to access and download any available SI. The methods detailed in the above SI are used by Public Analysts to determine whether a fertilizer conforms to the Fertiliser Regulations 1991 (and subsequent amendments), which is available at the website: The British Standards Institute has published their BS fertilizer analysis methods, and these are listed in pages 728-729 of Watson (1994), e.g. nitrate nitrogen is method BS 5551.

The European Commission Directive 77/535/EEC of 22 June 1977 on the approximation of the laws of the Member States relating to methods of sampling and analysis for fertilizers is obtainable at:

106 © 2002 CAB International. Methods in Agricultural Chemical Analysis: a Practical

Handbook (N.T. Faithfull) where there are links to subsequent amendments from 1979 to 1995.

The Government of India Fertilizer (Control) Order 1985, Schedule-I, Specifications of Fertilizers, is downloadable from: and Schedule II, Part A, dealing with sampling, and Part B, Method of Analysis of Fertilizers, is available at: The methods of analysis are mainly based on those of the AOAC (1965 edition) and the National Plant Food Institute, Washington, DC, 1961.

Methods of fertilizer analysis are also occasionally reviewed in the Proceedings of the International Fertiliser Society, and the contents of all the Proceedings are viewable at: The following is only a selection of analytical methods because there would be too many to include in a handbook dealing with many substances besides fertilizers. However, the references to articles, and the websites of official methods will provide an extra resource. Warning! - It should be emphasized that there are occasional misprints in official methodology (e.g. in the EU method for citric acid extractable phosphate in fertilizers, many full-stops appear as '7', so the citric acid monohydrate appears as having 7H2O); only purchased printed versions are actually 'official'. The methods below should give acceptable results in an educational/research context, but may not be as rigorous as the official procedures; the latter should be followed in all cases where ensuing litigation may be a possibility.

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