The Studebakers plying up and down Havana’s boardwalk aren’t the best advertisement for dynamism and innovation. But if you want to see what tomorrow’s fossil-fuel-free, climate-change-resilient, high-tech farming looks like, there are few places on earth like the Republic of Cuba. Under the Warsaw Pact, Cuba sent rum and sugar to the red side of the Iron Curtain. In exchange, it received food, oil, machinery, and as many petrochemicals as it could shake a stick at. From the Missile Crisis to the twilight of the Soviet Union, Cuba was one of the largest importers of agricultural chemicals in Latin America....