This seems like such a natural solution to so many problems, not sure why this is not used more (I can only speculate that pesticide and chemical fertilizer companies have something to do it). I have heard about this practice being successfully used in China too, but the below link is about rice farmers in the Philippines that have found an ally as they try to protect their crops from pests and the effects of global warming. Farmers use ducks to help keep the water in their paddies fresh, and to get rid of weeds and other pests that could damage their crops. Duck manure also works as a good organic fertilizer, which helps to decrease the amount of money farmers spend on harmful pesticides.
Integrated rice-duck farming has helped farmers to spend less money on harmful pesticides.