A decade ago, a shockwave raced through the world’s agricultural markets. China opened its borders to foreign-grown soy. Ranchers in Argentina plowed under their pastureland and Brazilian farmers opened new acreage for planting. Almost overnight, the economies of those countries changed. Why did this happen? And why does it make sense to grow food and ship it around the world rather than raise crops close to home? A Princeton-led research team has found that one of the primary answers is water.