Review of rice-fish-farming systems in China - One of the Globally Important Ingenious Agricultural Heritage Systems (GIAHS)

Rice-fish-farming systems constitute a unique agro-landscape across the world, especially in tropical and sub-tropical Asia. Rice is a globally important staple food crop, with a wide distribution and constituting diversified varieties. The introduction of fish rearing to rice farming creates an integrated agro-ecological system. China boasts a history of 1700 years in rice-fish-farming practice. It is no longer a sole agro-production practice, but an agro-cultural pattern. Therefore, it has been listed by the Food and Agriculture Organization of the United Nations (FAO) and the United Nations Educational, Scientific and Cultural Organization (UNESCO) as one of the Globally Important Ingenious Agricultural Heritage Systems (GIAHS). Qingtian County of the Zhejiang province has been selected as a pilot conservation site. The rice-fish-farming systems in China diversify China's agro-landscape and favor the conservation of species variety of both rice and fish. The survival of deep-water rice, an indigenous rice variety, and Oujiang red carp, an indigenous fish variety, are cases in point. Being low external input systems, the rice-fish-farming systems necessitate only small amounts of pesticide and fertilizer. The application of pesticides can be lowered to 50% of that of modem, high-input rice production; sometimes, no pesticide application is required. The natural enemies of rice pests show a prominent rise, making the bio-control of rice diseases and pests highly feasible. The rice-fish-farming system is also of great significance in global food security and global change. It provides food and animal protein for subsistence farmers living in ecologically-fragile mountainous regions. It also reduces economic risks that these farmers potentially face. The nitrogen-fixation role of the system increased the content of organic matter, total nitrogen and total phosphorus in the soil by 15.6-38.5%. It also reduces the emission of CH4 by nearly 30% compared with traditional rice farming. However, the economical development and industrialization in China pose a threat to rice-fish farming and, consequently, the numbers of farmers involved in rice-fish farming are decreasing. This calls for the Chinese government to engage itself in the conservation and development of this system and to innovate the existing technologies. It would also be useful, in the meantime, to exploit and conserve rice-fish farming as eco-tourism resources, so that the income of the mountainous farmers can be increased and this important, indigenous agro-culture be conserved and developed. (c) 2006 Elsevier B.V. All rights reserved.