Affinity Water & Cambridge Water Cover-Crop Reverse Auction — Farmers Bid to Cut Nitrate Reaching Chalk Aquifers (England)

Affinity Water and Cambridge Water, with FWAG East, run an online reverse auction on the EnTrade platform in which farmers in South Cambridgeshire and North Hertfordshire bid the price per hectare they need to grow nitrate-capturing cover crops over winter, protecting chalk aquifers used for drinking water.
Bidders see the estimated nitrate saving of their bid and their competitive position live, and can edit bids until the auction closes; species that capture more nitrate (e.g. oil radish) and earlier sowing make bids more competitive.
The 2019/20 pilot involved 11 farms, 488 ha and an estimated 24 tonnes of nitrate captured. In 2020/21, 18 farms and over 800 ha were enrolled at an average of GBP 109/ha (GBP 105/ha in 2019), with a target of 37.4 tonnes of nitrate; Affinity Water reported all participating farmers successfully established their crops, and a later report cited nearly 40 tonnes captured. The scheme was extended to a third year.
Cautionary note: nitrate figures are modelled estimates of leaching avoided, not measured groundwater outcomes, and total programme cost and aquifer-level effect are not published in the sources found.

Read the full analysis: https://www.cambridge-water.co.uk/news/cover-crop-funding-scheme-to-reduce-nitrate-levels-in-groundwater-extended