Six fire engines were sent to Prizeley Road in Cleobury Mortimer shortly after 2pm on Thursday, and are still there now.
A Shropshire Fire and Rescue Service statement said: "At 2.02pm, SFRS Fire Control received a call. Six fire appliances including the incident support unit and the water carrier were mobilised from Cleobury Mortimer and Ludlow. An operations officer was in attendance.
"Also at the scene of the incident were the police.
"Approximately 13 acres of standing crops alight. Four high pressure hose reel jets and beaters in use."