Dystopian Euro Films

In return for his favor and wisdom, Zardoz demands a tribute from his chosen ones. Huge baskets of grain are loaded into the stone head. One of the grain containers has a prize inside: Zed. He digs himself out and takes a look around inside of God's head as the massive idol lazily motors its way through the foggy English sky. Eventually, a little man in a blue robe comes out and walks around. Zed shoots him, and then watches as the surprised fellow (it's Arthur Frayn, by the way) falls out of the idol's gaping maw. Arthur disappears into the fog with barely a sound.

"The death of grass" in US "No blade of grass" is one my favorite novel from the british author Samuel Youd, under the name of John Christopher. Well-know for the "The Tripods" saga, Youd wrote several good novels as "The year of the comet" The world in winter" "The little people".
The 1970's adaptation, directed by magiar native Cornel Wilde (Kornél Lajos Weisz), yes the Academy Award actor, focused on a chinese virus strain has infected rice,wheat and barley crops causing massive famine and leaving world descending into anarchy. In a medieval England, engineer John Cunstance, played by british actor Nigel Davenport (the founding member of the English Stage Company), drove his family and friends in a journey of perils and pains, trying to reach John's brother's potatos farm.

This is the movie behind Twelve Monkeys, both movie and series.