KNOWLEDGE
CENTRE

Chemically granulated fertilizer [photo] 

Chemically granulated

Omnia’s fertilizer is safe to use

By Vossie Wilsnach (Manager: Chemtech)

When exporting produce from South Africa to the European Union (EU), all products are sampled and analysed for traces of certain pesticides used during the growth stage. The reason for these tests is that the EU has recently published regulation (EU) 20126/75, stipulating that the maximum allowable levels of Fosetyl-Al (pesticide) residue for importing certain produce must be as low as 2 mg.kg-1.

In traditional agriculture, Fosetyl-Al is used from time to time on certain crops, e.g. avocado and nuts, to treat systemic diseases. (See the coloured box below for technical information on Fosetyl-Al.)

Recently, it was announced that South African producers need to ensure that their produce is within the EU limits when exporting. As a loyal subscriber to the Responsible Care® initiative, Omnia Fertilizer decided to have all its products independently tested to ensure it does not contribute to the levels of Fosetyl-Al residue on produce grown using its fertilizers.

Several grades of fertilizer, representing a wide spectrum of Omnia products, were analysed for Fosetyl-Al by SGS Germany. From the results, it is evident that Omnia’s fertilizers comply with the above-mentioned regulation. No Fosetyl-Al was detected in either the raw materials used in production processes, or in the final product sold to growers.

Producers can therefore rest assured that Omnia’s products are completely safe and do not contribute to the presence of Fosetyl-Al in any produce.

Some key facts about Fosetyl aluminium and phosphorous in fertilizer

Contributed by Koos Bornman (General Manager, Strategic Agricultural Services, Omnia Nutriology®)

Fosetyl-Al, which was registered by the US Environmental Protection Agency (EPA) in 1983 (EPA 1991), is an aluminium salt of the diethyl ester of phosphorous acid which is not the same as phosphoric acid.

Fosetyl and Fosetyl aluminium belong to the class of organophosphorus fungicides. Similar products or terms are phosphite, phosphonite and phosphonate. It is produced by using a particular form of raw material called phosphorous acid (H3PO3). This reduced form of phosphorous is not plant available as nutrient. It needs to be oxidized first to become plant available, which is a rather slow organic process in nature.

All fertilizer sources of Omnia Fertilizer (and commonly all over the world) containing phosphorous as plant nutrient are manufactured by using the fully chemically oxidized form of phosphorous namely phosphoric acid (H3PO4). In fact, in the EU it is specified that phosphorous acid and its derivatives may not be used in the production of fertilizers – it may be used for pesticide production only.

References

  • Brunings A.M. et al. 2015. Are phosphorous and phosphoric acid equal phosphorous sources for plant growth? University of Florida, IFAS Extension. Document HS1010.
  • EFSA. 2012. Reasoned opinion on the modification of the existing MRL’s for Fosetyl in potato, kiwi and certain spices. European Food Safety Authority (EFSA) Journal 2012; 10(12):3019.