Mark Pearson was prosecuted for not increasing his slurry storage to prevent the risk of pollution to comply with environmental regulations.
Pearson, of Hanford Farm, Hanford, near Blandford, pleaded guilty to the offence after a prosecution brought by the Environment Agency (EA).
He was fined £1,200 and also ordered to pay a victim surcharge of £480 and full costs of £4,075.
The EA has confirmed that additional slurry storage has now been installed.
Yeovil Magistrates Court heard that there had been multiple pollution incidents involving the farm since 2012 and Pearson had failed to construct adequate slurry storage capacity.
The farm is located in a Nitrate Vulnerable Zone, an area designated as being at risk from, or impacted by, agricultural nitrate pollution. Excess nitrates can harm the environment and humans by leaching into groundwater and polluting waterways.
Farmers in Nitrate Vulnerable Zones must follow rules governing slurry storage capacity as well as controls over when and how much spreading can take place.
Pearson had initially been given EA advice and guidance to increase storage.
In January 2019, an EA officer was out walking his dog when he noticed what appeared to be slurry in a stream. He traced the runoff to a field at Hanford Farm and took photographs as evidence.
The EA said that during a formal interview under caution, Pearson admitted that slurry spreading at the farm had caused the pollution.
A spokesperson for the government agency added that Pearson agreed to an enforcement undertaking – an alternative penalty to formal court proceedings – and he paid a contribution to the National Trust of £2,000 as a result as well as making a commitment to increase slurry storage.
However, the EA said that Pearson still did not complete the slurry lagoon.
The Agency charged with him with the original polluting offence for which he had offered an Enforcement Undertaking and in November 2024 he was ordered to pay a £2,500 fine.
Pearson was finally given an Anti-Pollution Works Notice setting out what improvement works were deemed necessary to reduce the risk of pollution, but the EA said he failed to comply with the deadline of October 1, 2024. The notice included a right of appeal, which was not exercised.
The EA said that a visit to the farm on October 16 confirmed no new slurry store had been completed.
Chris Westcott of the Environment Agency said: “Pearson has consistently failed to deliver on his promises to the Environment Agency that slurry storage would be increased. We first highlighted this issue in 2015.
“We have been more than patient with the farmer, but the promised improvements never materialised, and the offending continued which left us with no alternative but to pursue enforcement actions.”