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Reducing nitrogen loss from manure with slurry acidification technique

Reducing the loss of nitrogen from agriculture is key to reducing eutrophication of the Baltic Sea. Most of the airborne eutrophication of the Baltic Sea is due to ammonia emissions from livestock manure. Slurry acidification has long been known to effectively reduce or even stop ammonia from evaporation from animal manure

Acidification is a well-known technique used to reduce ammonia loss from livestock manure. When the pH of the manure is lowered, emissions decrease and nitrogen is stabilized into a plant-available form. Farmers benefit from the increased fertilizer value of slurry and the decreased need to invest in mineral nitrogen and sulfur fertilizers. The environment benefits from reduced ammonia-nitrogen emissions and reduced eutrophication.

Slurry acidification techniques (SATs) can be used at different stages of manure handling on pig and cattle farms. The techniques can be divided into three types:
• In-house acidification of livestock slurry
• In-storage acidification of stored livestock slurry
• In-field acidification of livestock slurry during field spreading.

Baltic Slurry Acidification project analyzed and studied different aspects of the techniques and their benefits to advance the implementation of SATs.


Project summary and overall conclusions

Slurry acidification technologies (SATs) are easily implemented on farms and have been shown to significantly reduce ammonia emissions from slurry

Ammonia emissions from livestock manure cause airborne eutrophication and other negative impacts on the environment. On top of that ammonia emissions represent an economic loss for farmers and lead to increased use of mineral nitrogen fertilizers. Slurry acidification technologies (SATs) developed in Denmark are easily implemented on farms and have been shown to significantly reduce ammonia emissions from slurry. The Baltic Slurry Acidification project has studied and analyzed different aspects of slurry acidification that could hinder adoption of these techniques, including worker health and safety, potential corrosive effects on concrete and equipment, effects on soils as well as legislative barriers.

In general, no major barriers were found that would directly hinder implantation of current slurry acidification technologies in Baltic Sea Region (BSR) countries. There was considerable interest among farmers in these technologies and their benefits, however, there was also concern about investment and running costs. In conclusion, SATs are effective green tech solutions that will reduce nitrogen loss from agriculture, do not negatively affect yields and can be easily implemented, however, incentives or compensation mechanisms are necessary to initiate investments and implementation of SATs. We recommend all BSR countries to establish national expert groups to further examine the potential for SATs to be implemented as an abatement measure to reduce national ammonia emissions.

Erik Sindhöj,

Project Coordinator


Erik Sindhöj

Contact person

Erik Sindhöj

Senior Forskare

+46 10 516 69 12

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