South African police on Wednesday arrested dozens of striking farmworkers as protest over low pay turned violent in parts of the Western Cape Province.The arrests were made after farmworkers stoned cars, burnt tyres and blocked roads with rocks, prompting riot police to intervene. Police have detained at least 50 people since the protests began early Wednesday, according to police spokesman Lieutenant Colonel Andre Traut.The most affected area is the town of De Doorns, a flash point of protests in November last year, Traut said.Roads leading to the town were closed, forcing motorists to use alternative routes. Some motorists coming from the town said the situation there was volatile.The protest involved thousands of farmworkers who resumed their strike after their demand for higher pay and better living conditions was rejected by farm owners.In the town of Grabouw, the strike went on relatively peacefully as striking farmers were dancing and singing in their march to the commercial center under the watch of a large contingent of heavily-armed police.Organizers said the massive strike action would involve major farming towns in the province, capable to bring agriculture to a standstill.The South African government has urged farmworkers to refrain from violence in the strike and to exercise their right to protest peacefully, legally and within the ambit of the law.The Congress of South African Trade Unions (COSATU), which organized the strike, also called for a peaceful strike, but said non-violence could not be guaranteed.