'Calculation method unsuitable for low-emission stables'

I-VEE supports projects that aim for emission-free and climate-neutral livestock farming, both in the Netherlands and worldwide. The reason for the I-VEE research is the doubt that exists about the effectiveness of low-emission stable floors. "The doubt causes problems with the granting of permits and leads to the annulment of granted permits. In line with this, the Ammonia and Livestock Regulations (RAV) - the national list of emission factors for low-emission systems - may even be up for discussion," said I-VEE.

Professor Sven Gjedde Sommer from Aarhus University (Denmark) and Carin Rougoor and Frits van der Schans from CLM Research and Advice note that there is a great deal of variation in sampling and analysis of nitrogen and phosphate in animal manure and that there is a high degree of inaccuracy is in the CBS calculations. "It is doubtful that the average of manure analysis figures from a selection of stables guarantees the average of all stables in the relevant category," Sommer notes in a statement. "Given these inaccuracies and variations, the nitrogen - which cannot be attributed to one source in the CBS calculation - should not be regarded as solely ammonia emissions from stables. Sommer advocates a thorough statistical analysis of the CBS figures to show whether there is any residual nitrogen at all. Rougoor believes further research is necessary. "The fact that the CBS analysis structurally provides a higher estimate for ammonia emissions than is expected on the basis of national emission data, without it being possible to prove why this difference occurs, indicates that additional research is necessary."

Further research already underway
But guess what? When asked, CBS reports that further investigation is already being conducted. "The uncertainties mentioned in the CBS report are the reason for further research and this has been going on for some time and is being carried out by Wageningen Livestock Research," said a response from CBS. As CBS emphasizes, this is not a CBS calculation method. The principle of the measuring method used in the CBS report was developed by the Commission for Experts in the Fertilizer Act (CDM). CBS applied the method on behalf of the CDM to the data available at CBS. The measuring method estimates the magnitude of the total nitrogen loss between production and manure discharge. "It is therefore more than just ammonia and more than just emissions from stables," according to CBS. The CBS report only concerns conventional stables and stables with low-emission floors and/or manure cellars. Low-emission stables with air scrubbers are not taken into account.

"There are now some practical data available showing that low-emission stables are not significantly better than conventional stables: Low-emission-floors-convince-not-in-practice.pdf (stichtingagrifacts.nl) en 536752 (wur.nl). But we are waiting for the findings of Wageningen Livestock Research," the statistics agency said.