For rice farmers, ducks have been a viable way to keep their crops healthy -- they destroy weeds, eat bugs and fertilize crops without using harmful chemicals. And now, a Nissan technician might have an alternative when fowl isn't an option. He's testing a robot 'duck' that roams rice paddies, muddying the water to prevent weeds from getting enough sunlight to grow -- it's really a Roomba (and a cute one at that) for watery fields. Although it's a personal project, it's fully realized with GPS, a WiFi connection and solar power to minimize its environmental impact.