"The farm owner has been arrested for attempted murder," said Lt Col Andre Traut on Wednesday.
He said about 8 000 farm workers gathered to protest in De Doorns on Tuesday.
"The situation is calm. They are slowly dispersing and more police have been deployed to maintain order."
Wouter Kriel, spokesperson for provincial agriculture minister Gerrit van Rensburg, said the reasons for the protest were not immediately clear.
"There is no specific leadership and no list of demands … one thing that is very important is to get dialogue going."
The N1 highway was closed between Touws River and De Doorns on Monday when farm workers gathered on the road, and over 30 hectares of vineyards were destroyed in the protest.
Western Cape police said at the time the cause of the protest was likely to be a wage dispute, but the agricultural department disputed this.
"This is not a labour strike and [is] not organised by farm workers, even though farm workers are involved. It seems to be politically motivated," Kriel said.
"There is a lot of intimidation going on. We have a lot of seasonal labour on the farms starting for [the] grape season. We are adamant that it is not traditional workers who are involved, but the seasonal workers."
The Congress of South African Trade Unions in the Western Cape said it supported demands by farm workers and residents of De Doorns for a living wage and decent living conditions, with basic services and proper housing plans.
"Many of the farmers have been exploiting the farm workers for too long in the agricultural sector, and this needs to come to an end," provincial secretary Tony Ehrenreich said. "People cannot be expected to live on their knees, whilst the farmers profit handsomely from the exploitation."
He called on workers and residents not to resort to violence.
The Democratic Alliance (DA) said the protest was politically motivated.
"It is very clear to me that much of the protest in this area is politically motivated and the local ANC is once again played a large role in inciting the violence and vandalism," said Ivan Meyer, leader of the DA in the Western Cape.
"A volatile situation such as this one should under no circumstances be exploited for cheap political gain. The DA condemns such behaviour in the strongest sense."
Meyer said the mayor of the Breede Valley municipality, Basil Kivedo, addressed the protesters on Tuesday afternoon.
"Through intense … discussions with all the stakeholders, we managed to defuse today's conflict … Our swift reaction and leadership proved that it is possible to find solutions through dialogue." – Sapa