An integrated social and natural sciences case study for the reuse of organic wastes as soil amendments

Societal Impact Statement

Reusing organic waste materials, such as animal manure, as soil amendments reduces water and fertiliser demand, contributing to achieving the Sustainable Development Goals. However, organic wastes may contain contaminants of emerging concern (CECs), posing potential ecosystem and human health risks. Despite the importance of this issue, there is a lack of open dialogue between researchers studying CECs and the farming community, limiting farmers' awareness of potential risks and researchers' understanding of realistic agricultural scenarios and constraints. Furthermore, farmers face financial, practical and policy challenges when deciding whether to use organic amendments; decisions are often made without a shared understanding of broader environmental concerns.

Summary

The aim was to address the lack of communication between farmers and researchers from various disciplines by integrating research on contaminant of emerging concern (CEC) presence and their effects on arbuscular mycorrhizal (AM) colonisation, with insights from social anthropology.

A UK farm using a combination of wastewater biosolids, farmyard manure and synthetic fertiliser as soil amendments on three fields served as a case study. CEC presence and impact on AM colonisation was evaluated for soil from each field. The farmer and farm manager were interviewed to understand financial, practical and policy challenges around organic amendment use. Finally, a UK-wide stakeholder workshop presenting the case study results to farmers, and other stakeholders was undertaken.

The presence of 16 chemicals, including human and veterinary pharmaceuticals, pesticides and industrial chemicals across the three fields was confirmed. There was no significant effect on AM colonisation depending on which field the soil was from. A recorded interview of the farmer and farm manager demonstrated that their agricultural practices are motivated by both environmental consciousness and economic pragmatism. During the workshop, seven research questions were identified. Topics included what information is or should be available for farmers to make decisions on waste reuse in agriculture, for example, CEC presence. In addition, concerns were raised on how specific farming practices affect CEC fate and effects and how adequate policy on waste reuse is.

This work integrates chemical, biological and social considerations surrounding soil amendment choices, emphasising the need for interdisciplinary collaboration and informed decision-making in sustainable agriculture.