浙江青田“稻魚共生系統(tǒng)”歷史悠久,，延續(xù)了1200年,，2005年被聯(lián)合國列入 "globally important agricultural heritage systems, GIAHS",。浙江大學(xué)陳欣教授研究團隊經(jīng)過6年的試驗研究,，揭示物種間的正相互作用及資源的互補利用是稻魚共生系統(tǒng)可持續(xù)的重要生態(tài)學(xué)機制,。
“稻魚共生系統(tǒng)”中鯉魚通過沖撞稻秧,，導(dǎo)致rice planthopper（昆蟲綱同翅目飛虱科害蟲，俗名火蠓蟲）落入水中,，降低其對水稻危害,，研究人員通過錄像和控制實驗詳細重現(xiàn)了此過程。同時,，鯉魚沖撞能夠使清晨水稻葉片露水墜入水中,，減少稻瘟病原孢子產(chǎn)生和菌絲體生長，降低其對水稻危害,。同時鯉魚取食甚至連根拔起許多雜草,，顯著降低稻田雜草數(shù)量。
作為回報,，水稻再給魚類提供食物（昆蟲和水稻葉片）的同時,，還能夠抵擋烈日照射，降低表層水溫,，除此之外,，水稻能夠利用氮素,，降低水中銨鹽濃度，為魚類生長創(chuàng)造良好環(huán)境,。
相比常規(guī)水稻單作模式,，稻魚共生系統(tǒng)能夠降低68的殺蟲劑和24的化肥施用。
和傳統(tǒng)水稻田一樣,，稻魚共生系統(tǒng)面臨甲烷排放的困擾,，尤其水淹時間延長，其排放量可能有贈無減,。但是化肥施用量的減少,，能夠降低另一重要溫室氣體-氧化亞氮的排放。同時,，為降低農(nóng)業(yè)生產(chǎn)中的氮素過量施用提供了很好的解決方法,。
總之，陳欣教授的研究成果為綠色水稻生產(chǎn)提供了好的模式,，將中國幾千年來勤勞,、淳樸而又充滿大智慧的農(nóng)民推到世界科學(xué)的前沿。PNAS同期刊發(fā)了亞利桑那大學(xué)Lansing的評論,，稱其利用傳統(tǒng)混作農(nóng)業(yè)中的生態(tài)遺產(chǎn)為我們上了一堂可持續(xù)農(nóng)業(yè)課,，推動了生態(tài)農(nóng)業(yè)發(fā)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.
