Over the thousands of years humans have spent farming the Fertile Crescent, it has never ceased to be a hotbed of innovation. Today, Iraqis are experimenting with a type of agriculture that may reshape the region: growing plants without soil. As global warming and environmental degradation cause irreversible changes to the composition of Iraq’s farmland, the soil-free, water-saving science known as hydroponics offers the country of 40 million — home to two of the world’s most famous rivers — a chance to adapt to this new reality. Meanwhile, the international community will be waiting to see wh…