Associated Press: A hardy but pedestrian plant is doing triple duty in California’s agricultural heartland, absorbing a salt that once deformed waterfowl by the millions, creating clean-burning biofuel and nourishing cattle with the leftovers. Crop-crippling selenium in soil and groundwater makes the arid west side of the San Joaquin Valley a challenge for farmers, whose diesel tractors have been blamed for helping cause the worst air quality in the nation. But farmers, water managers and …