Riley turned down Land's petition late Wednesday afternoon, a little more than 24 hours before Land is to die of lethal injection at 6 p.m. Thursday in Alabama's death chamber at Holman Prison in Atmore.
The 41-year-old Land was sentenced to die for the May 1992 slaying of 30-year-old Candace Brown of Birmingham.
He was convicted of breaking into her home, kidnapping Brown and fatally shooting her in the head.
Brown's body was found by hikers in a limestone quarry on Birmingham's Ruffner Mountain.
Brown has not filed a last minute court appeal and the clemency petition appeared to be his final chance to stop the execution.