稻渔综合种养的科学范式

21世纪是渔业的世纪。中国和世界水产业历经数十年的发展为人类应对食品危机做出了巨大贡献。然而,我国传统的水产业对产量的片面追求导致养殖环境日趋恶化,养殖生态系统不断退化,养殖业的可持续发展受到限制。传统稻田其氮素的流失亦是导致农业面源污染的主要原因之一。我国当前的环境问题源于复合生态系统演化进程的缺陷,解决当前的环境问题,必须从优化复合生态系统演化进程着眼。采用优化的生态循环水产养殖模式,如综合水产养殖则可以大大提高氮、磷等养分物质的利用率。稻渔综合种养是一种科学的复合生态模式,可以概括为三种模式,一种是在我国传统稻田养鱼的基础上,逐步发展起来的一种稻渔共生模式,可采取稻鱼、稻蟹、稻虾等多种共作形式;二是稻田作为湿地用于处理水产养殖尾水的模式,属于异位处理形式;三是将稻渔共生和水产养殖相耦合的模式,尤其是与多种水产养殖形式结合或与复合水产养殖系统相结合,甚至是与农牧系统相结合。这第三种稻渔共作模式又称为陆基生态渔场,具有高产、高品质、高生态可持续性等特点,应加强对该创新养殖模式中有机碳、氮、磷等营养收支平衡和循环利用的相关机制以及复合生态系统对外源营养输入的整体响应机制开展研究。概括而言,尾水排放是传统池塘养殖中氮源的主要流失途径,颗粒物吸附沉降是池塘养殖中磷源的主要流失途径,而系统中的碳源则主要是通过鱼类等生物的呼吸作用进行消耗。基于生态循环的"稻渔共生-池塘复合生态系统"则恰好可以解决这三大类营养物质在生态系统中的高效保持和利用问题,实践业已证明该复合系统拥有较高的产量、品质和生态效益,是一种可持续的农业发展模式。稻渔复合生态系统的创新模式因其特有的生态循环机制及系统的高弹性、高缓冲性、高可持续性,将成为我国乃至世界应对农田、渔业生态系统的退化,复合高效解决渔业、农业或农牧业生态环境问题的典型范式。

Scientific paradigm of integrated farming of rice and fish

The 21st century is a century of fisheries. After decades of development, China and the world''s aquaculture industries have made great contributions to human response to the food crisis. However, the one-sided pursuit of production by China''s traditional aquaculture industry has led to a gradually deteriorating aquaculture environment and continued degradation of aquaculture ecosystem. The sustainable development of aquaculture is limited. Nitrogen loss in traditional paddy fields was also one of the main triggers for agricultural non-point source pollution. The current environmental problems in China stem from the defects of the evolutionary process of complex ecosystems. To solve the environmental problems, it is necessary to focus on optimizing the evolutionary process of complex ecosystems. Using the optimized ecological cycling aquaculture modes, such as integrated aquaculture, can greatly increase the utilization of nutrient substances such as nitrogen and phosphorus. Integrated farming of rice and fish (IFRF) is a scientific complex ecological mode. IFRF can be summarized as three models. The first model is a rice-fish symbiosis model which had been gradually developed on the basis of traditional rice-field fish culture in China, taking the forms of rice-fish, rice-crabs, rice-shrimps and other forms of farming. The second one is to use rice paddies as wetland for treatment of aquaculture drainage, belonging to a form of off-site treatment. The third one is a coupled model of rice-fish farming and aquaculture, in particular, in combination with various forms of aquaculture or with the complex aquaculture system, even with agriculture and animal husbandry system. The third model is also known as land-based ecological fishery. It has some characteristics of high yield, high quality, and high ecological sustainability. More researches should be developed on the mechanisms of nutrient balance and recycling about the organic carbon, nitrogen and phosphorus in this innovative culture model, as well as the overall response mechanism of the complex ecosystem to external sources of nutrient inputs. In general, drainage is the main pathway of nitrogen loss in traditional pond aquaculture, and particle adsorption and settlement are the main sink to mitigate phosphorus in pond culture. Carbon source in the system is mainly consumed through the respiration of fish and other organisms. The "rice-fish symbiosis-pond complex ecosystem" based on ecological cycling is just a solution to the highly effective conservation and utilization of the above three categories of nutrients in the ecosystem. Practice has proved that this composite system had high yield, quality and eco-efficiency, and it was a model for sustainable agricultural development. Due to the unique ecological circulation mechanism, high resilience, high buffering capacity, and high sustainability, the innovative complex ecological mode of integrated farming of rice and fish will become a paradigm of China and even of the world to respond to the degradation of agriculture and aquaculture ecosystems, as well as to solve the eco-environmental problems in aquaculture, agriculture, and agro-pastoral industries comprehensively and effectively.