Evaluation of rice-reed-fish model in salinized wetland of west Songnen Plain, China

With a total land area of 3.73 million hm², 1 million hm² of west Songnen Plain is a salinized wetland. This is a major factor inhibiting agricultural development in the region. Rice-reed-fish model was established in accordance with the characteristics of salinized wetlands in the plain. The model is developed to increase biological diversity and water and fertilizer use efficiencies through mutually beneficial linkages between rice,reed and fish farming. In the rice-reed-fish system,drainage from the rice field serves as irrigation source for planktons,and the planktons in turn serve as feed source for the fish. Then loamy earth on the lake bed is used as organic fertilizer for paddy rice cultivation. Ten years after establishment, soil salinity has reduced from 4.54g/kg to 2.98g/kg and soil organic matter content has increased from 16.43g/kg to 24.45g/kg in the rice paddy.An additional advantage is that the model parameters are flexible and can be adjusted to reflect the objectives of the system.