Hundreds of tonnes of baled straw went up in flames in Great Paxton on Friday.
Firefighters from St Ives, Huntingdon, Ramsey, Chatteris, St Neots, Papworth, and Gamlingay attended the incident and arrived to find approximately 500 tonnes of baled straw alight in a field off Dovecote Lane at about 9pm.
A spokesman for Cambridgeshire Fire and Rescue Service said: "Using hose reels and drags firefighters dampened down the burning straw bales before returning to their stations by 9.50pm."
Crews continued to monitor the blaze until Sunday.
The cause of the fire is currently under investigation, the spokesman added.