浙江青田“稻鱼共生系统”历史悠久，延续了1200年，2005年被联合国列入 "globally important agricultural heritage systems, GIAHS"。浙江大学陈欣教授研究团队经过6年的试验研究，揭示物种间的正相互作用及资源的互补利用是稻鱼共生系统可持续的重要生态学机制。
“稻鱼共生系统”中鲤鱼通过冲撞稻秧，导致rice planthopper（昆虫纲同翅目飞虱科害虫，俗名火蠓虫）落入水中，降低其对水稻危害，研究人员通过录像和控制实验详细重现了此过程。同时，鲤鱼冲撞能够使清晨水稻叶片露水坠入水中，减少稻瘟病原孢子产生和菌丝体生长，降低其对水稻危害。同时鲤鱼取食甚至连根拔起许多杂草，显著降低稻田杂草数量。
作为回报，水稻再给鱼类提供食物（昆虫和水稻叶片）的同时，还能够抵挡烈日照射，降低表层水温，除此之外，水稻能够利用氮素，降低水中铵盐浓度，为鱼类生长创造良好环境。
相比常规水稻单作模式，稻鱼共生系统能够降低68的杀虫剂和24的化肥施用。
和传统水稻田一样，稻鱼共生系统面临甲烷排放的困扰，尤其水淹时间延长，其排放量可能有赠无减。但是化肥施用量的减少，能够降低另一重要温室气体-氧化亚氮的排放。同时，为降低农业生产中的氮素过量施用提供了很好的解决方法。
总之，陈欣教授的研究成果为绿色水稻生产提供了好的模式，将中国几千年来勤劳、淳朴而又充满大智慧的农民推到世界科学的前沿。PNAS同期刊发了亚利桑那大学Lansing的评论，称其利用传统混作农业中的生态遗产为我们上了一堂可持续农业课，推动了生态农业发展。(生物谷 Bioon.com)
doi:10.1073/pnas.1111043108
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Ecological mechanisms underlying the sustainability of the agricultural heritage rice–fish coculture system
Jian Xie, Liangliang Hu, Jianjun Tang, Xue Wu, Nana Li, Yongge Yuan, Haishui Yang, Jiaen Zhang, Shiming Luo and Xin Chen*
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 us develop novel sustainable agriculture. We examine how rice–fish coculture (RF), which has been designated a “globally important agricultural heritage system,” has been maintained for over 1,200 y 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. We 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. Our 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.
