Pieter Hills was killed at the scene, and his son Eddie was seriously injured after being shot in the neck.
Eddie passed away in hospital on Wednesday.
Four people have been arrested in connection with the attack, one of which died while in police custody on Saturday.
The remaining three suspects have appeared in court, and their bail application was set for 16 November.
The FAS plans to attend the bail application of the accused.
“Courts must take note of the public’s anger and frustration with murder in the rural areas. The court must take us into account when considering bail for accused people who commit crimes in rural areas, specifically farm murders,” said FAS president Francois Wilken.
The FAS also said that another farmer from Odendaalrus, Mark Regal, has been killed.
“Our country has lost another farmer, a food producer. The crime onslaught on the agricultural sector and in our country continues unabated and this is unacceptable. Farmers, but also the public as a whole, are no longer prepared to allow the lawlessness,” Wilken said.
Details of the protest would be announced soon. Participation is free but the FAS has requested that all participants act within the law and the protest arrangements at all times, said Wilken.
Compiled by Nica Richards