Asparagus (芦笋) is a very odd vegetable. It can grow up to 2cm in an hour. Cut a field one afternoon, return the next morning, and with almost frightening speed it will be back. Whereas other vegetables spend time producing leaves, asparagus grows as single spears (嫩茎), making it superbly suited to robotic pickers.
In late June a small white object slowly makes its way along a field of asparagus in Gloucester-shire. When it passes over a group of spears it pauses, whirr then clunks: the asparagus has been sliced. This robot called Sprout is being developed by a London start up called Muddy Machines. It is more inflexible on wheels than Ex Ma-china android. However, John Chinn, Britain's largest asparagus producer, regards it with enthusiasm. For him, he says, it could be "fantastic".
The world is suffering from a shortage of seasonal workers. Last summer Mr. Chinn needed 1, 300 workers. He got around 800. Trying to find labour is, for a farmer, "the thing that stops you sleeping". The shortage of workers is particularly acute in Britain, where Brexit (英国脱欧) has been spoiling harvests as well as growth.
Now, it is a time to innovate. Moravec's paradox (莫拉维克悖论)states that computers find things simple that humans find hard——and vice versa. Differential calculus (微分学)? Not a problem. Telling the difference between a ripe strawberry and a stone? Really hard. Harvesting is especially ripe for robotic puzzlement. Leaves confuse them; bumps puzzle them; colour prevents them. In 2015, Joe Jones, a robotics whose inventions include the Roomba, a vacuum cleaner, was considering new areas to explore, and started to make a list of which crops a robot might be able to pick most easily. He considered different variables (变量) that "would make it easy for a robot to handle", then scored each crop out of 12. "And what crop, "he wrote on his blog, "came out on top?"
In the fields of Gloucester shire is the answer. Sprout crawls forward; pauses. Another whirr, whoosh, clunk. It is an original model, but Mr. Chinn is optimistic. His dream would be to see a herd of 100 in his fields next year. He needs them. The stress is now so bad that "If we can't find a solution, we'll all give up soon."
