Multiple choice Which of the following is used as a good biofertiliser in rice fields? Azolla Moss Green legume Cow dung Reveal answer Fill a bubble to check yourself A Correct answer Explanation Azolla is used as a good biofertiliser in rice fields. Azolla is a floating pteridophyte, which contains an endosymbiont, the nitrogen-fixing cyanobacterium Anabaena azollae (Nostocaceae family).