The accident happened at about 9.45 am on Rue des St Germains in St Lawrence, and the driver was taken to hospital with a suspected broken arm.
The chemical tank was also damaged as the tractor fell on to its side and 1,700 litres (373 gallons) of pesticides poured out on to the road and along a farm track.
The Fire and Rescue Service attended the scene, and Jersey Water diverted the pool of pesticides away from the surrounding streams. Officers from the Environment Agency and the Health and Safety department also attended, and the Fire Service said that no chemicals directly entered the water supply.
