Abstract: Nitrogen derived from water hyacinth and recovered in rice crops was measured to evaluate the effect of different amounts of added water hyacinth residues into rice cultivation on the performance of rice crop, N derived (Ndev) from residues and N recovery (Nrec) in rice crop. Dry matter production and N yield of rice crop decreased significantly as the amounts of added water hyacinth increased. The Ndev from water hyacinth was significantly increased as amounts of added water hyacinth increased. In contrast, the Nrec in rice crop was significantly decreased as amounts of added water hyacinth increased. In conclusion different quantities of added water hyacinth residues influenced the performance of rice, and the N dynamics of soil-rice systems.