Fire crews were out fighting a blaze near the village of Burghwallis for five hours last night.
The fire involving two large haystacks followed another in the same area off Crabgate Lane the previous day, when over 100 bales of hay had been destroyed.
Two fire appliances from Adwick attended from 7pm until midnight.
A spokesman for South Yorkshire Fire and Rescue service said: “Crews will be back on site this morning to check the scene over.
“We believe the fire was started by kids. A small group was spotted leaving the scene and moving in the direction of Skellow.”
Police carried out a helicopter search and police dogs were used on the ground in a bid to find the culprits.
The owner of the torched hay stacks is believed to live near Pontefract and rents the farming land.