Alan Frame, an employee with farming giant Lawrie & Symington, was working on Bonnington Farm in Lanark when the accident happened at around 6.20pm on Monday.
A member of the public witnessed what happened and raised the alarm, but the 41-year-old died at the scene. Last night, Mr Frame's father Iain, who also works as a yard foreman at the company, said his son's death was devastating for the family.
Mr Frame, of Lanark, who leaves behind his wife Lee, had worked with the farming firm since leaving school.
Police said a post-mortem examination would take place in the next few days to establish the exact cause of death, but there appeared to be no suspicious circumstances.
Hunter Murray, manager-director at Lawrie & Symington in Lanark, said Mr Frame's colleagues and the customers he worked with were all deeply saddened by his death.
He added: "It's tragic. He was working at the time and a member of the public spotted him and raised the alarm. Alan was a loyal and hard-working employee of Lawrie & Symington and had been for 26 years.
"He was a nice chap and a very popular person who was well known among the staff and customers and he will be sadly missed. Our sympathies go out to his family at this time."
Mr Frame's neighbour James Imrie also told of his shock at the farm worker's death.
He said: "I knew Alan quite well and we found out near enough right away what had happened. It was such a shock.
"We just heard that he fell off the quad and by the time they got to him they were too late. It's absolutely tragic."
Mr Frame's funeral will take place in Lanark a week today.
A Strathclyde Police spokesman said: "A 41-year-old man was riding a quad bike on marshland at Bonnington Farm, Lanark, when it overturned, trapping him beneath. He died at the scene.
"A post-mortem will take place in due course to establish the exact cause of death, however, there would appear to be no suspicious circumstances surrounding the incident."