Investigating the impact of slurry acidification on soil and crop quality

Status: Ongoing

Contact person: John Langley (john.langley@bangor.ac.uk) / Prof Dave Chadwick / Prof Davey Jones

Funding source: Defra

Background: Acidification of slurry – the process of lowering slurry pH from around 8 to 6 using sulphuric acid – is effective in reducing ammonia and greenhouse gas emissions at different stages of slurry management. However, little information exists regarding the impact of slurry acidification on soil and crop quality.

As part of a Defra-funded project, replicated experiments will be undertaken at 6 field sites (including Henfaes research centre), representative of different soil types, cropping and agro-climatic zones in England and Wales. In each year, there will be two applications of acidified and unacidified slurry, spring and summer, which will be applied using bandspreading and broadcasting techniques for comparison. Four repeated applications are also to be assessed for potential cumulative impacts on soil health. Additional synthetic N response plots will be included to quantify the impact of acidification on N fertiliser replacement value.
The study explores the effects of slurry acidification on soil chemical, physical and biological properties, as well as crop yields, crop quality and nutrient use efficiency.

Aims:

• Assess biogeochemical factors that impact soil and crop quality following acidification
• Assess the impacts of acidified slurry application by measuring impacts on soil quality, including soil pH changes, and ammonia emissions.
• Identify the potential impacts and practicality of using acidification technology in the UK

Collaborators: ADAS, Rothamsted Research