Effect of rice-fish/shrimp co-culture on sediment resuspension and associated nutrients release in intensive aquaculture ponds

Abstract

ABSTRACTRice-fish co-culture has gained increasing attention in the restoration of water quality of intensive aquaculture. However, the effect of rice-fish co-culture on sediment resuspension, a key process regulating the nutrients recycling in the aquaculture water, has rarely been investigated. In this study, a field experiment was conducted to investigate the impact of rice-fish co-culture on sediment resuspension and associated nutrients release in the yellow catfish and freshwater shrimp ponds. The results showed that the concentrations of nitrogen and phosphorus in the water were significantly lower in the co-culture ponds than monoculture ponds. Additional rice cultivation significantly reduced sediment resuspension rate (R) by 68.0% and 58.8% in the catfish and shrimp ponds, respectively. The total amount of nitrogen and phosphorus released from sediment resuspension were respectively mitigated 18.15 g m−2 and 9.21 g m−2 in the catfish pond and 7.79 g m−2 and 4.52 g m−2 in the shrimp pond, which was higher than that accumulated in rice plants. Increasing rice planting density strengthened the inhibition on sediment resuspension and associated nutrients release. These results indicated that the mitigation of rice-fish co-culture on sediment resuspension played an important role in the restoration of the eutrophication of aquaculture water.