New report helps stakeholders assess environmental impacts
Slurry acidification drastically reduces ammonia emissions, and it’s also a promising technique for the abatement of methane and nitrous oxide emissions. However, to maximize the benefits and avoid certain pitfalls knowledge and common sense must be used.
As Baltic Slurry Acidification is approaching its conclusion several reports will be published. The work of the project is organized into six different work packages, all investigating different aspects of slurry acidification techniques (SATs).
The newly finished report “Main environmental considerations of slurry acidification”, written by the Estonian Crop Research Institute, is the main output from work package 5. The aim of the report is to provide a literature-based understanding of the environmental effects of slurry acidification. Work package 5 has been responsible for increasing the knowledge concerning the environmental and economic impacts of SATs to build end-user confidence in SATs. The report provides groups such as farmers, advisors and authorities at various levels with the knowledge necessary for assessing the environmental impact of livestock operations.
The environmental effects of implementing slurry acidification should be assessed and accounted for from a variety of perspectives – in addition to emissions, consideration needs to be given to the impacts on soil chemistry and quality. The life cycles of different acidification technologies and their long-term implications on farm management need to be assessed.
Covering a variety of environmental parameters, the report concludes that slurry acidification decreases environmental burdens, largely because it reduces ammonia emissions. In‐house acidification systems reduce ammonia emissions throughout the whole manure management chain and reduce several greenhouse gas emissions, more than the other two types of SATs.
According to the report, attention must be paid to the nutrient and pathogen leaching and higher survival of some pathogens, when dealing with SATs. Since the highest risk of pathogen leaching is immediately after slurry application, slurry application should be avoided when rainfall is expected. To reduce the risk of plant root and groundwater contamination by E. coli bacteria, surface application of slurry is recommended. As acidified slurry can be applied on the surface without the risk of ammonia losses, acidification can be also a good method to reduce the risk of contamination by E. coli. Good practical knowledge and common sense must be used in farm management practices to maximize the positive effects of SATs.
On the other hand, regulators need to assume a holistic, multi-dimensional approach across various environmental and policy objectives. Though SATs have the potential to radically reduce ammonia emissions, the abatement of this single pollutant does not provide a sufficient argument for their implementation. Slurry acidification is, however, a promising technique for the abatement of methane and nitrous oxide, too, when optimized over the different stages of the manure management process.