Research shows dairy farms in Pembrokeshire are over-importing phosphorus, contributing to river pollution while missing opportunities to save on fertilizer costs.
Key facts
- •The Cleddau rivers are designated special areas of conservation but suffer from elevated nutrient levels that deplete oxygen for aquatic life.
- •The annual phosphorus surplus in the region is estimated at 360 tonnes, equivalent to the weight of 26 double-decker buses.
- •First Milk is analyzing the nutrient footprints of 700 farmers across the UK, including 200 in west Wales.
- •The research suggests that better management of on-farm manure could replace the need for much of the artificial fertilizer currently purchased.
- •The Cleddau nutrient management plan is supported by the Welsh government to address phosphorus and nitrogen pressures.
A new Lancaster University study funded by the Welsh government identifies agriculture as the primary driver of phosphorus pollution in Pembrokeshire's Cleddau rivers. Researchers found that local farms import significantly more phosphorus through fertilizer and feed than is exported in products, leading to a surplus that degrades water quality. By optimizing the use of existing manure and slurry, farmers could potentially reduce costs and help restore the rivers.
By the numbers
Excess Phosphorus and Economic Impact
The Cleddau rivers, which flow through an area producing 25% of Wales' milk, have been labeled the country's poorest performing protected waterways by Natural Resources Wales. The study found an annual surplus of approximately 360 tonnes of phosphorus remaining in the land. Researchers suggest that farms could save an estimated £1.08 million annually by relying on existing manure nutrients rather than purchasing expensive artificial fertilizers.
Industry-Led Mitigation Efforts
The dairy co-operative First Milk is working with 200 farmers in west Wales to calculate individual nutrient footprints. Using satellite imagery and field-level mapping, the initiative aims to guide where farmers spread slurry and fertilizer to minimize runoff. This effort aligns with the UK Food and Drink Pact, which includes a commitment from major supermarkets to source 50% of fresh food from areas with sustainable water management by 2030.
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This article was independently rewritten by ManyPress editorial AI from reporting originally published by BBC Science & Environment.
