Fish and rice flourish together in paddies
SciDev.Net, 16 November 2011

LONDON, UK: A traditional farming technique that cultivates rich and fish side-by-side could help small farmers earn more money from their crops and reduce the impact on the environment, according to a study published in the Proceedings of the National Academy of Science on 14 November. Researchers examined how rice-fish co-culture (RF), which has been designated a “globally important agricultural heritage system,” has been maintained for over 1,200 years in south China. A field survey demonstrated that although rice yield and rice-yield stability are similar in RF and rice monoculture (RM), RF requires 68% less pesticide and 24% less chemical fertilizer than RM. A field experiment confirmed this result. It was documented that a mutually beneficial relationship between rice and fish develops in RF: Fish reduce rice pests and rice favors fish by moderating the water environment. This positive relationship between rice and fish reduces the need for pesticides in RF. Results also indicate a complementary use of nitrogen (N) between rice and fish in RF, resulting in low N fertilizer application and low N release into the environment. These findings provide unique insights into how positive interactions and complementary use of resource between species generate emergent ecosystem properties, and how modern agricultural systems might be improved by exploiting synergies between species. For centuries, traditional agricultural systems have contributed to food and livelihood security throughout the world. Recognizing the ecological legacy in the traditional agricultural systems may help develop novel sustainable agriculture. Read the article … Download Ecological mechanisms underlying the sustainability of the agricultural heritage rice-fish coculture system, by Jian Xie et al, PNAS 14 November 2011, doi: 10.1073/pnas.1111043108 [pdf] …