Eight fire engines are in attendance after a blaze engulfed 40 acres of trees and standing crops in Chelmondiston.
The fire is in Ling's Lane.
Emergency crews from Colchester, Wivenhoe, Ipswich East, Woodbridge, Orford, Aldeburgh, Southwold, Halesworth, Needham Market and Hadleigh fire stations are battling the blaze.
This is the fourth field fire reported in Suffolk today, with similar incidents reported in Claydon, East Bergholt and Little Glemham.
Four hoses are being used, and crews have deployed a drone to assist with the operation.