RESUMO
The effect of feed residues on release law of nitrogen and phosphorus in water-sediment interface was studied under the simulated condition in laboratory. Two sets of conditions were applied in this study, static condition (A group) and feed add condition (B group). The results show that DO in A group is higher than that in B group (P < 0.05). The pH value is neutral in A group, but pH value of B group became weak acidic. After adding the feed, nitrate nitrogen concentration in A group is higher than that in B group (P < 0.05), but orthophosphate concentration in A group is lower than that in B group (P < 0.05). At the 2-14th day of experiment, ammonia concentration in A group is higher than that in B group (P < 0.05), but since then the ammonia concentration in B group begins to rise. At the end of the test, ammonia concentration in B group is higher than that in A group (P < 0.05). At the beginning of the experiment, ammonia and nitrate nitrogen release restrained in B group. Nitrogen increases first, and then decreases in A group, but the changing regulation is completely opposite in B group. Feed decomposition can produce a large amount of phosphorus in B group, at the same time, orthophosphate changing regulation increases first and then decreases.
