It's true. The Japanese government's Ministry of Agriculture has begun an ambitious project called the "Dream Project" which involves unmanned robotic tractors farming on land that was devastated by the earthquake and tsunami of 2011. Read the full story here.
What strikes me about this story is it is another reminder of the difference between how we (Americans) see robots and how the Japanese see them. For the most part, Japanese society sees robots as a beneficial helpers. Even in their popular culture they've had characters like Astro Boy, Doraemon, Robocon and Arale. Not to mention the slew giant robot heroes like Gaiking, Raideen and Mazinger.
While we do have friendly characters like Wall-E, Number Five (Short Circuit) and C3PO + R2D2 we also have that Skynet Terminator thing in the back of our minds giving way to a certain amount of distrust (or like HAL from 2001: A Space Odyssey and Joshua from War Games). But looking at the real world applications of robots in the US there seems to be a lot less experimentation in using them for more humanitarian purposes. We've got some pretty bad ass robotic military machines though! Meanwhile the Japanese are developing therapeutic robotic pets for senior citizens. What gives?