The laboratory study, carried out in partnership with Lancaster University, tested several Herefordshire soil types to see whether gypsum could help prevent phosphorus from being washed out of farmland and into watercourses such as the River Wye. 

The findings were presented to the Wye Catchment Nutrient Management Board, which brings together organisations working to improve water quality along the river.

The results showed that adding gypsum reduced the amount of phosphorus that can be easily washed out of soil into water, mirroring results of other studies and suggesting its applicability in Herefordshire. 

The size of the reduction varied depending on the type of soil and how much gypsum was used.

Importantly, there was no clear change in the amount of phosphorus available for plants to use, suggesting that gypsum application would not negatively affect a plants access to this essential nutrient.

The Council says the findings provide encouraging early evidence that gypsum could form part of a wider package of measures to help reduce the impact of agriculture on local streams and rivers.

Herefordshire Council’s Deputy Leader and Cabinet Member for Culture and Environment, Cllr Elissa Swinglehurst, said: 

“Protecting the health of the River Wye and our wider river catchments is a priority, and we are always looking for practical solutions that support both farmers and the environment.

“These early results are encouraging and suggest gypsum could help reduce the amount of phosphorus reaching our rivers, while still allowing farmers to maintain productive soils.

“The next step is to test this approach in real farming conditions to see how effective it can be at a larger scale.”

The idea for the research project came from local farmer Ben Taylor-Davies of Townsend Farm, Ross-on-Wye, who follows regenerative agriculture practices on his farm.  Regenerative farming focuses on improving soil health, minimising disturbance of the soil and maximising the diversity of plants.

Speaking about the trials, Ben said:

“It’s rare that a waste product can be recycled to provide a huge benefit to soils and their structure, capture excess phosphates with no detrimental effect on crop availability and therefore reduce the pollution risk to our watercourses with no negative effects. In high magnesium soils, Gypsum provides a practical and useable solution.”

The Council will now work with partners to develop field-scale trials. These trials will test gypsum applications on working farms to better understand how the approach performs in real-world conditions, including its effectiveness over time and any wider impacts on soil health and crop production.

•   Read the full report: Gypsum for phosphate retention in soil (Item 8) in the Wye Catchment Nutrient Management Board agenda.