This policy is especially useful if you have plenty of domestic Trade Routes and seek to grow your cities taller. The +4 Food from every domestic Trade Route can add up quite quickly and grow your cities to record heights. Just make sure that the Citizens have enough Housing to grow at normal rates and enough Amenities to keep them happy and prospering, or risk Barbarians spawning in your cities.
As a result of a looming famine and two million ton shortfall in grain in 1928 AD, Stalin claimed the grain was being hoarded by kulaks. At a plenary session of the Central Committee in November 1929, the Politboro embarked on a program of collectivization of agricultural production in the Soviet Union … by force. Between 1929 and 1940, over 91% of all agricultural production was “converted” into collective farms (kolkhozy); the rural, peasant-owned farmland was subjected to industrialization and mass production to feed the exploding urban population and supply cash exports (since most capitalist countries wouldn’t trade for anything else with Russia). Although more efficient and controllable, collectivization never saw Soviet agriculture reach pre-Revolution production levels.