Ammonia emissions mean a loss of nitrogen fertilisers for agriculture. They also pollute the environment. Part of the losses occur during slurry storage. In order to reduce these losses, artificial covers are required for new slurry containers. Tent roofs and floating foils in particular have caught on as artificial covers. The less permeable the cover, the more effectively it reduces emissions. Apart from this, no explosive gas-air mixture must be allowed to evolve under the cover, as happens when the methane concentration lies between 4.4 and 16.5 volume per cent (vol. %). A minimum air exchange must therefore prevent this concentration from being reached. Just how high the minimum ventilation rate must be depends on the maximum methane emission rate. The latter is influenced by several factors such as the qualities and temperature of the slurry, the temperature under the tent roof, and the thickness of any natural floating layers. How these factors affect the release of gas under practical conditions is to date unknown. For this reason, emission measurements were performed at a slurry silo with a tent roof at the ART for different external conditions and ventilation rates. Both the methane concentration as well as the ammonia and carbon dioxide concentration in the outgoing air flow were measured. The measurement results allowed us to deduce the minimum ventilation rate. From this, the necessary cross-section of the ventilation openings for any slurry containers with a tent roof can be calculated with a view to safe operation.
The reduction of environmental risks from plant protection products is to be monitored by the Confederation using a risk indicator. The indicator also takes into account the degree of implementation of risk reduction measures in practice. This degree of implementation was estimated by a study.
Arbuscular mycorrhizal fungi are important for healthy soils and crops. A pan-European study shows that plant-protection products adversely affect these fungi, reducing their ability to supply plants with phosphorus via their roots.
A comparison of different methods of winter-wheat fertilisation with nitrogen showed that nitrogen surpluses can be significantly reduced by means of site-specific variable-rate nitrogen fertilisation.