Nitrogen in mineral concentrates mainly occurs in the form of ammonium. The organic nitrogen content is low (on average 10% of the nitrogen). The ammonium is immediately available for crop intake, but a part of the ammonium can volatilize as ammonia. Organically bound nitrogen is available to the crop after mineralization in the soil. According to the Nitrates Directive, mineral concentrates, as processed manure, must be applied within the application standard for animal fertilizers (ie 170 kg N / ha / year). The discussion about the possibility of using mineral concentrates as mineral fertilizers is still ongoing.
Various pilot projects have been running in the Netherlands since 2009. Wageningen University conducts experiments on large-scale application of mineral concentrates in the Netherlands. Both the functioning of mineral concentrates, as well as the agricultural and environmental effects, as well as the assessment of whether these effects are similar to those of artificial fertilizer, are being investigated.
Companies participating in the research can apply mineral concentrates outside the application standard for animal manure, while the application standards for phosphate and nitrogen are valid and the available amounts of nitrogen and phosphorus are 100%. .