Police are working with the fire service in Cambridgeshire to try to tackle the problem of straw stacks being set on fire.
Officers said the fires cost businesses thousands of pounds and have a "dramatic effect" on the rural community.
"With a shortage of hay this year it is vital that we crack down on these offenders," said Pc Robin Smith.
"Those responsible are risking their lives and the lives of others."
Martin Boome, arson investigation unit officer for Cambridgeshire Fire and Rescue Service said: "The fire service takes a strong view about any kind of fire which is started deliberately - including stack fires.
"This type of fire has the potential to kill not only those in the nearby vicinity, but also the arsonists themselves.
"We are working closely with the police to reduce this type of fire and to bring offenders to justice."