Ammonia emissions: Mitigation is urgently needed
Ammonia emissions: A reduction is urgently needed
Agriculture causes about 95 percent of ammonia emissions. Ammonia and the ammonium it produces damage ecosystems through acidification and eutrophication, and they are also precursors of harmful particulate matter.
NH3 emissions can be effectively reduced with improved application methods for farm manure. Source: Landpixel
Germany must drastically reduce ammonia emissions in the coming years: by 29 percent by 2030 compared to the reference year 2005. This is what the NEC directive, which came into force at the end of 2016, calls for. The reason: ammonia (NH3) is harmful to the environment. Human health. Affected by the tightening is mainly agriculture. It alone is responsible for 95 percent of all NH3 emissions.
A great challenge for agriculture
The planned reductions pose a major challenge to the industry. As part of the international agreement on air pollution control (NEC Directive), Germany has undertaken to comply with an emission ceiling of 550 kilotons of NH3 per year as of 2010. However, this goal has not always been achieved since then. In some years, the limit value was just exceeded. For compliance with the NEC Directive, the total NH3 emissions minus the energy crop-related contribution are decisive in this context. In 2019, total ammonia emissions were 586.6 kilotons, of which 557.8 kilotons were from agriculture, which includes 57.8 kilotons of NH3 emissions from energy crop fermentation.
NH3 emissions from German agriculture from 1990 to 2019. Dotted in black is the reduction pathway under updated NEC guidance, which calls for a 29% reduction in 2030 from 2005 levels. Source: Thunen Institute for Agricultural Climate Protection
Main source of emissions: agricultural animal husbandry as well as farm manure management
By far the most important source of ammonia emissions in 2019 was agricultural livestock and manure management, accounting for a total of about 77 percent of agricultural NH3 emissions. Livestock excreta contain high levels of ammonium nitrogen, which is converted to gaseous NH3 upon contact with the atmosphere. 20 percent of agricultural NH3 emissions come from cattle farming, 16 percent from swine farming, 6 percent from poultry farming, and about 1 percent from other livestock production. Livestock grazing accounts for 2 percent of agricultural NH3 emissions. Farm manure application accounts for 31 percent of agricultural NH3 emissions. The application of urea-containing mineral fertilizers a further 12 percent. About one tenth of agricultural NH3 emissions are due to the fermentation of energy crops, including the application of digestate.
Ammonia: Harmful to the environment and health
NH3 is a gas that has negative impacts on the environment and human health. It damages near-natural ecosystems through acidification and nutrient oversupply, accompanied by a change and decrease in biodiversity. Ammonia is also considered an indirect greenhouse gas because it can be converted to nitrous oxide. Nitrous oxide is around 300 times more harmful to the climate than carbon dioxide. The emission of NH3 also causes particulate matter formation. Thus endangering human health. Scientists at the Max Planck Institute for Chemistry in Mainz identified ammonia as the most important cause of air pollution, especially in large parts of Europe, in a study published in 2017. According to the researchers, 250 per year worldwide could.000 deaths attributable to air pollution would be avoided if agricultural ammonia emissions were 50 percent lower.
How NH3 emissions can be reduced?
The greatest potential for reduction lies in the management of agricultural and mineral fertilizers; the main aim here is to keep contact with the atmosphere as short as possible. The implementation of some measures is already foreseen in the Fertilizer Ordinance, which was amended in 2017, but with different implementation deadlines. For example, some methods of spreading liquid farm manure that result in high emissions have been banned since 2016.
Figure element description:
Near-natural ecosystems like this wetland are damaged by NH3 emissions Source: Landpixel
The new fertilizer ordinance also stipulates that liquid fertilizers must be incorporated within four hours on uncultivated farmland. Since 2020, this incorporation requirement also applies to poultry manure and to mineral fertilizers containing urea, if no urease inhibitor was added. In addition, liquid fertilizers may only be used on cultivated arable land from 2020 onwards. From 2025 onwards on grassland, they may only be applied in strips or directly into the soil.
In general, the faster farm manure is incorporated, the more NH3 emissions can be avoided. If only strip application were carried out on uncultivated arable land, this would also reduce NH3 emissions. Also expensive, but very effective, are disc slitters and slurry cultivators. They can be used to introduce liquid manure directly into the soil. There is further emission reduction potential in the gas-tight covering of slurry and digestate outdoor storage facilities. Measures such as slurry cooling or slurry acidification or improved exhaust air purification of pig and chicken houses can also be considered.
However, German agriculture is still far from implementing such steps in some cases. Either because they are too expensive or not yet developed enough. Or, because their introduction would require far-reaching changes to existing law. One obstacle is certainly also that various mitigation potentials conflict with increasing animal welfare requirements: For example, in the future, husbandry methods with outdoor runs will gain in importance, which have an increased NH3 emission potential.
Brochure: BZL brochure "The new fertilizer regulation"
What the Fertilizer Ordinance means for agricultural and horticultural practices is the content of the new brochure "Fertilizer Ordinance 2020. The revised Fertilizer Ordinance came into force on 1. May 2020 in force. To the 1. January 2021 the new regulations for the "red" areas (areas polluted with nitrates and eutrophic areas) will also become effective.
Other EU countries are already further ahead
Other EU countries are partly far ahead of Germany in terms of NH3 emission reduction. According to DLG (DLG-Mitteilungen 4/2018), Denmark, for example, was able to reduce its NH3 emissions from agriculture by almost 15 percent between 2005 and 2016. The obligation introduced in Denmark as early as 2002 that liquid manure must be spread close to the ground has made a particular contribution to this. In addition, for a good ten years now, the Danish authorities have not approved any building permits for pigsties without conditions for emission-reducing measures.
In milk production, the Danes have been able to increase the efficiency of milk production by improving feeding, management and breeding, so that only 2.9 grams of NH3 emissions would be produced per kilogram of milk. Germany is at 5 grams of NH3 per kilogram of milk here. This means that Danish dairy cows are significantly more efficient in terms of their environmental impact.
Other EU countries were also able to noticeably reduce their NH3 emissions from agriculture between 2005 and 2016. Romania, for example, by about 19 percent, the Netherlands, Finland and Croatia by about 17 percent. For comparison: In Germany, NH3 emissions have increased by 6 percent in this time period.