"The minister of agriculture signed a regulation to determine intervention purchase prices for third-class corn," a ministry spokesman said.
The source said prices would be set at 3,300 rubles for the Urals and Siberia and 3,100 rubles for European Russia.
Agriculture Minister Alexei Gordeyev said earlier that interventions, for which Rosselkhozbank received 6.5 billion rubles ($227.68 million) from the budget, would begin August 29.
The government intervenes when corn prices plunge on the market. After excessive volumes of corn are curbed, the decline stops. The measure is used to support national corn producers and stabilize the situation on the corn market.