The incident happened at Gutardi village in the district's Savli tehsil, an official said.
He informed that labourers were loading sand allegedly excavated illegally from the farm when the embankment gave way, burying the labourers under sand, a Desar police station official said.
He identified the deceased as Ravindrakumar Vankar, Kalpesh Gohil, Nagin Vanzara and Bhailu Vanzara.
"A case of accidental death has been registered and the bodies have been handed over to their families following post mortem," sub-inspector Kiritsinh Vahatsinh told news agency PTI today.
The four were taken to hospitals in Kalol and Savli where doctors declared them dead on arrival, the official said.
Village sarpanch Jayesh Bakrola claimed that he had complained about the illegal excavation being carried out the farm on June 15 to an official but no action was taken.
Sub-inspector Mr Vahatsinh said that investigations into the incident were underway.