ABSTRACT
This chapter describes field trials to determine the benefits of integrating rice and fish using azolla as a nitrogen fertilizer for rice and a feed ingredient for fish. Studies on rice-fish-azolla mixed culture were initiated in the Philippines in the mid 1980s. They were initially focused on assessing the effectiveness of fresh azolla as a feed supplement for giant tilapia. The chapter provides additional information needed to understand the short and long-term advantages of using azolla to help sustain food production levels in irrigated rice fields. The good yield in the former can probably be attributed to two factors: wider space with greater water depth, and a fairly balanced homemade ration found to be as effective as commercial feeds in promoting fish productivity. Seasonal changes in yield response might be related partly to a significant improvement of soil fertility, which was probably associated with continued utilization of azolla as an alternate source of nitrogen.
