Interactions of the anaerobic soil microbiome with crop protection products under laboratory and field conditions.

Crop Protection Products (CPP) e.g. fungicides, herbicides, pesticides are used globally to control pests and disease in agriculture. To register CPP, persistence in soils must be determined to ensure CPP will not pose a risk to human health or the environment. Persistence testing guideline 307, from the Organization for Economic Co-operation and Development (OECD), recommends soils must be tested under both aerobic and anaerobic conditions in a laboratory. However, substantial discrepancies have been observed between laboratory and field studies, with CPP often degrading faster in the field. Discrepancies may result from deviations from natural conditions during OECD testing, including the loss of key anaerobes during soil handling. As a result, laboratory OECD testing may misrepresent the persistence of CPP in the environment.

Preliminary work investigated microbial communities from anaerobic waterlogged soils and compared f indings with existing microbial datasets to gain an understanding of the microbial communities present in anaerobic agricultural soils. This dataset forms the baseline against which we will determine changes in the anaerobic soil microbial communities when subjected to different stages of soil handling during OECD 307 testing procedures.

Outcomes aim to provide recommendations for improvements to OECD 307 guidelines for the handling of anaerobic soils during regulatory testing. Furthermore, the interactions of CPP with anaerobic soil microbial communities will be elucidated to resolve differences in persistence between laboratory and f ield trials. Through the use of standard regulatory studies combined with microbial ‘omics, improvements in conceptual models of the environmental fate of CPP are anticipated.