The incident took place last night when Suraj Jatav, aged around 30 years, along with his brother, raised objection to the digging of land close to their farm by the four persons, they said.
Jatav's farm is located near Rooparel river in Ramgarh.
After an argument, the accused identified as Hakku, Jamsher, Ajroo and Mosim allegedly crushed Jatav under the JCB, Additional Superintendent of Police Alwar, Paras Jain said.
The victim was admitted to a local hospital with critical injuries where he died during treatment today, he said.