A blaze which destroyed 200 tons of straw was started deliberately, firefighters believe.
More than 100 firefighters have been involved in dealing with the fire near Henfield since Saturday night.
They were called to Horsham Road, Ashurst, at 10.30pm.
A barn containing 200 tons of straw was badly damaged and its contents completely destroyed.
Crews from around West Sussex have been monitoring the site since the blaze was put out in case it catches light again.
Anyone with information about the fire is asked to call Sussex Police on 0845 6070999.
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