Alan Blinder, esteemed Princeton economics professor and former vice-chairman of the US Federal Reserve, recently found himself owning up to a surprising new interest: the soyabean.

“I never knew much about soya before,” Blinder confessed on the sidelines of an economic conference in Aspen this week, as he presented his latest forecasts. “But I want to find out. Who would have ever imagined that!”

Not many people. Western policy makers and eminent economists have mostly ignored the bean, figuring it to be a rather dull agricultural crop. I never paid much attention to soya myself, associating it with hippie dishes and tofu. But last month the US government released figures showing that the country’s exports had surged in the second quarter of this year, pushing up the annualised rate of GDP growth to a heady 4.1 per cent. Part of the reason was the humble soyabean.

Most notably, when the Chinese government declared earlier this year that it would impose 25 per cent tariffs on soya imports, amid the escalating trade war, US farmers dashed to offload vast quantities of beans into China, as well as other markets, ahead of the sanctions.

This delivered record levels of soya exports in May, and boosted those GDP numbers. Some economists, such as Jeffrey Dorfman, a professor at the University of Georgia, think the overall impact was not significant; others, such as Ian Shepherdson at Pantheon Macroeconomics, suggest those soya sales could have boosted GDP growth by as much as 0.6 percentage points. Either way, one thing is now crystal clear: soya is no longer being ignored.

The soya saga is thought-provoking for several reasons. First, it is a timely reminder that not everything that matters in the modern world is linked to digital technology or cyberspace; sometimes it is the old-fashioned things that we need to watch, before they trip us up.

Second, it’s high time we paid far more attention to the role soya has been playing on the geopolitical stage recently — even before these latest sanctions hit. Over the past decade, while most pundits have been busy obsessing about cyberspace, something rather remarkable has been happening — largely unnoticed — in agriculture.

The agricultural world has long been aware that soya is so protein-rich it can not only be fed to humans but can also be crushed up to make a perfect animal feed. As Asian consumers have become wealthier in recent years, they are now eating far more chicken and pork. And, where Chinese household farms used to feed their animals with kitchen scraps, they now turn to soya meal to fatten those chickens and pigs. Brazilian and US farmers have rushed to cater to an exploding new source of soya demand. As a result, it has become the fastest-growing crop in the world — and this spring the amount of land planted with soya eclipsed that for corn to become the biggest single US crop. Which is, of course, precisely why the Chinese have targeted the bean: they know the tariffs will hit US farmers where it hurts.