The Bishop Dike project aimed to assess the effectiveness of alternative approaches to sediment and nutrient management upstream in reducing or removing flood risk and ongoing channel maintenance costs downstream associated with sediment build up and excessive weed growth. Effectively, does resolving one of the causes (excess sediment and nutrient entering the watercourse upstream from agricultural sources) reduce the costs needed to resolve the symptom (excess weed and sediment deposition downstream)?
From 2020 through to March 2023 Yorkshire Dales Rivers Trust (YDRT) worked with the EA, Catchment Sensitive Farming (CSF) and Yorkshire Integrated Catchment Solutions Programme (iCASP) to investigate this question.
Sediment modelling across upper Bishop Dike showed that improving soil management, particularly through increased organic matter, had the potential to reduce sediment runoff by as much as 46% according to iCASP’s modelling of the catchment.
YDRT engaged with farms across the area, offering a package of free comprehensive soil testing followed by a soil health event:
In December 2022 farmers from across the area joined YDRT, CSF and Yara Lancrop for an evening soil health event held in Sherburn in Elmet. CSF presented collated anonymised soil test results from each of the farms who’d received soil sampling. This stimulated conversations around differing results, from organic matter to levels of different key nutrients and pH, each element contributing towards the success or failure of crop growth and many elements effecting the likelihood of soil erosion and nutrient runoff. Lancrop went into greater detail, discussing soil health through chemical, physical and biological status and how by considering all three it can be possible to reduce unnecessary spending on excessive crop applications, optimise crop yields all whilst better supporting the environment and the health of farm soils.
Of particular interest was how beneficial soil organic matter is for typically improving soil structure, moisture retention and water infiltration and how levels can be increased through reduced tillage, the use of cover crops and increasing external organic inputs such as through manures and green waste composts. Organic matter results ranged from around 2.4% through to nearly 7% and demonstrations of water infiltration tests using two different soil samples during the talk got the group discussing the merits of improved organic matter for their farms. The importance of soil pH was also highlighted and how much pH can limit nutrient availability and biological activity. The conversations were positive, revolving around thinking more deeply about farm applications and all of the wider details that influenced crop health.
All attendees agreed they would continue to look further into increasing their organic matter and whilst some were already following elements of best practice including cover cropping after potato crops and chopping straw or other organic matter into the fields post harvest, all agreed there were areas they would look to improve on in the future.