Thousands of years of rice and fish without artificial inputs
Raising fish in rice paddies has been practised for at least 1700 years in Viet Nam and continues to be reinvented to this day. Producing both types of food, this environmentally friendly and flexible system doubles the chances for securing a household’s food supply without the use of chemical fertilizers, herbicides or pesticides, says Elisabeth Simelton
In northwestern Viet Nam, over nearly two thousand years, farmers have mastered growing a carefully considered mix of carp and tilapia in wet rice fields: the fish eat weeds, bugs and molluscs that carry pests; their waste acts as fertilizer; and they stir up sediments that also release nutrients that help the rice grow. This integrated system provides benefits that each component by itself would not be able to achieve, creating ‘more than the sum of its parts’. It has been sustained without the need for artificial inputs such as fertilizers, herbicides and pesticides.
However, starting with the Green Revolution of the 1960s, farmers worldwide have been encouraged or, in some cases, required to use chemical fertilizers, herbicides and pesticides to increase yields, with the now-well-documented accompanying harmful effects on the environment and human health. The rice-and-fish farmers of northwestern Viet Nam have been encouraged by the national food security policy to employ these practices but farmers do continue to use traditional methods and they negotiate with their neighbours who don’t to regulate the flow of water to avoid pesticides and herbicides poisoning the fish.
A study in the country’s Mekong Delta has confirmed that this kind of restricted use of agri-chemicals can protect biodiversity and improve yields. The researchers compared rice and rice–fish farmers in the Cần Thơ and Tiền Giang provinces of the Delta in 2007, with a specific focus on pesticide use. They found that in Cần Thơ, rice–fish farmers had significantly higher income than other types of farmers but the rice–fish farmers of Tiền Giang didn’t, which the researchers indicated could be partly caused by these farmers employing a high use of insecticides and having comparatively low fish yields.
Another feature of the rice-and-fish system is that it is more resilient to changes of conditions than either of the two components alone. For example, under normal conditions the expected harvest is rice and fish. However, if there is a drought or a flood, the fish can be transferred to a pond or river and there is still the chance of a harvest of fish. If water supply is normal but the fish die for whatever reason, there is still a rice harvest. In contrast, monocultural systems face a greater risk of failure under increasingly variable, and extreme, climatic conditions.
The rice-and-fish practice has been proven over generations, spread from farmer to farmer, without the need for government agricultural extension (advisory) services or civil society organizations. The components—that is, the particular species of rice and fish—and the technology—the irrigation system—were both familiar to farmers, as were the economic and environmental risks and benefits. By contrast, so-called ‘improved’ farming systems—with unfamiliar trees, crops or technologies—quite often fail. For example, if a visiting technician sees that it makes sense to grow even familiar plants along the land’s contours, there might be good reasons why the farmer hasn’t done so already.
One of the most important lessons to be drawn from the traditional rice-and-fish farmers of northwestern Viet Nam is similar to that from complex agroforestry systems: that future agricultural systems should not just provide a single product, such as rice, but be designed to produce a range of integrated services, such as rice, fish, pest control, nutrient recycling, fodder, clean water, carbon stock and landscape beauty.
Edited by Robert Finlayson
Berg H, Berg C, Nguyen TT. 2012. Integrated rice-fish farming: safeguarding biodiversity and ecosystem services for sustainable food production in the Mekong Delta. Journal of Sustainable Agriculture 36: 859–872.
Simelton E. 2013. Socioeconomic and environmental trade-offs for multifunctional landscapes: rice-fish Bac Kan. Technical workshop on methods and experience in climate change research and assessments in fisheries and aquaculture in Viet Nam. Slideshow. Hanoi: WorldFish; Viet Nam Institute of Fisheries Economics and Planning.
Xie J, Hu L, Tang J, Wu X, Li N, Yuan Y, Yang H, Zhang J, Luo S, Chen X. 2011. Ecological mechanisms underlying the sustainability of the agricultural heritage rice-fish coculture system. Proceedings of the National Academy of Sciences of the United States of America 108:E1381–E1387.