THEY make an intriguing posse: about 160 “scouts” in jeans and muddy boots, jumping out of cars with ropes in hand, plunging deep into corn (maize) and soyabean fields across the American Midwest. They are not just farmers. They include commodity traders and hedge-fund managers. Their quest: to predict this year’s harvest by using ropes as a measure and counting, to the last ear of corn and soyabean pod, the yield in a given area. “We have a really beautiful crop. I think this is going to be a record,” says Ted Seifried, a market strategist at Zaner Group, a commodities brokerage in Chicago, during a stop in Nebraska on August 21st. The mud on his boots is a reassuring sign of ample moisture in the soil.
But when he gets back into the car with others on the Pro Farmer Midwest Crop Tour, the talk turns to darker subjects, such as trade tensions, collapsing currencies and what he calls the start of an “economic cold war” between America and China. “While we’re driving the 15-25 miles from field…
