【作者】 盛锋；

【导师】 曹凑贵； 李成芳； 汪金平；

【作者基本信息】 华中农业大学 ， 作物栽培学与耕作学， 2019， 博士

【摘要】 稻鸭共育技术运用生态学原理,实现动物和植物间的互利共生,是发展生态农业的重要举措。当前,已有大量研究报道了稻鸭共育对土壤肥力、温室气体排放、水生生物、水稻生长等的影响,然而,结合温室气体排放综合评估稻鸭复合系统生态经济效益的研究尚显薄弱。因此,本研究通过2009²010两年的大田试验,研究了稻鸭共育对稻田土壤和水体营养元素、水生生物、温室气体等的影响,并综合分析了稻鸭共育系统的生态经济效益。本研究结果为实现绿色农业和农业可持续发展提供了理论依据。主要研究结果如下:（1）稻鸭共育显著改善稻田土壤氧化还原状况,增强土壤酶活性,增加土壤速效氮含量。稻鸭共育处理较常规稻作处理提高土壤氧化还原电位（Eh）,增幅达28.8⁴4.0 mV（P<0.05）。与常规稻作处理相比,稻鸭共育处理使土壤脲酶、脱氢酶、过氧化氢酶与蛋白酶活性分别显著提高了28.3%⁴8.3%（P<0.05）、27.2%³0.3%（P<0.05）、13.3%¹56.2%（P<0.05）和19.9%²7.6%（P<0.05）。稻鸭共育模式下,NH₄⁺-N、NO₃^--N和微生物量氮含量分别较常规稻作提高了32.5%⁴2.7%（P<0.05）、24.6%²6.2%（P<0.05）和12.6%¹6.7%（P<0.05）。（2）稻鸭共育显著提高田面水溶解氧（Dissolved oxygen,DO）浓度,增加田面水无机氮和总磷含量,增加了水体富营养化的风险。相对于常规稻作处理,稻鸭共育处理田面水DO平均含量增加了20.0%²2.0%（P<0.05）。在稻鸭共育期间,与常规稻作处理相比,稻鸭共育处理总氮含量提高81.1%¹01.1%（P<0.05）,总磷含量提高32.7%⁴1.2%（P<0.05）,NH₄⁺-N含量增加45.4%⁸0.0%（P<0.05）,NO₃^--N含量增加11.8%¹8.3%（P<0.05）。（3）稻鸭共育显著降低田面水藻类和水生动物种类与生物量,导致稻田水体水生生物多样性降低。与常规稻作处理相比,稻鸭共育处理绿藻门与蓝藻门种类显著降低了21.3%²6.7%（P<0.05）与29.9%³2.9%（P<0.05）,硅藻门、绿藻门与蓝藻门生物量分别下降46.7%⁵2.9%（P<0.05）、27.1%²9.0%（P<0.05）与13.6%⁴7.1%（P<0.05）,藻类辛普森指数和香农指数分别降低11.6%²4.5%（P<0.05）与9.9%²1.3%（P<0.05）。与常规稻作处理相比,稻鸭共育处理轮虫生物量、枝角类与桡足类水生生物量和总原生动物生物量分别降低36.1%⁴8.2%（P<0.05）和34.6%⁴1.0%（P<0.05）。相关性分析表明,硅藻门、蓝藻门、绿藻门的种类数、生物量均与各种氮、磷营养盐呈显著负相关,裸藻门种类数、生物量则与所有氮、磷营养盐呈显著正相关。（4）稻鸭共育可影响稻田N₂O和CH₄排放,进而影响全球增温潜势（Global warming potential,GWP）。与常规稻作处理相比,稻鸭共育处理N₂O排放量提高6.1¹5.5倍（P<0.05）,CH₄排放量下降32.0%³2.7%（P<0.05）,GWP显著降低约28%（P<0.05）。稻鸭共育处理较常规稻作处理增产2.7%³.6%（P<0.05）,温室气体排放强度（Greenhouse gas intensity,GHGI）显著下降41.3%⁴4.8%（P<0.05）。结构方程模型分析表明,稻鸭共育主要通过三个过程影响温室气体排放。即通过鸭子活动（例如觅食等）抑制水生生物和促进土壤与大气交换,提高田面水DO浓度和土壤Eh;或通过鸭子排泄和活动等行为提高土壤无机氮;或通过觅食行为抑制水稻无效分蘖,促进水稻生长,进而影响N₂O和CH₄排放。（5）基于N₂O和CH₄排放的生态经济效益分析表明,与常规稻作处理相比,稻鸭共育处理经济效益（Economic benefit,EB）显著提高37.8%³9.2%（P<0.05）,生态经济效益（Net ecosystem economic benefits,NEEB）提高39.7%⁴0.8%（P<0.05）,表明稻鸭共育是一项低碳丰产的稻田种养模式,是符合当前国家的“水稻+”绿色高质高效生产模式之一。综上所述,稻鸭共育系统可有效提高土壤与水稻速效养分,改善土壤氧化性,显著降低CH₄排放,降低综合温室潜势。同时,由于稻鸭共育抑制杂草、藻类与原生动物生长,使得系统资源得到充分利用,提高了水稻产量、系统经济与生态效益,因此,稻鸭共育模式是当前是水稻绿色生产的重要模式之一,对于确保国家口粮安全、推进绿色兴农、实现质量兴农具有重要意义。更多还原

【Abstract】 Integrated rice-duck farming is one of important measures of ecological agriculture.The farming system utilizes the mutualism of duck and rice based on ecological priceples.Recently,much research reported effects of the farming on soil fertility,greenhouse gas（GHG）emissions,aquatic organism and rice growth,but few studies focused on economic and ecological benefits based on GHG emissions under the rice-duck farming system.Therefore,a field experiment was conducted in central China to assess effects of the rice-duck farming on N and P content of soil and floodwater,aquatic organism and GHG emissions,and also to evaluate the economic and ecological benifites.The results of this study provided scientific basis for realizing green and sustainable agriculture.The results were shown as below.（1）Integreted rice-duck farming significantly improved soil oxidizability,enhanced soil enzyme activity and increased soil inorganic N contents.Compared with conventional rice culture（R）,rice-duck culture（RD）significantly increased Eh by28.8⁴4.0 mV,urease activity by 28.3%⁴8.3%,dehydrogenase activity by27.2%³0.3%,catalase activity by 13.3%¹56.2%,and protease activity by19.9%²7.6%,and thus enhanced NH4⁺-N,NO₃^--N and microbial N contents by32.5%⁴2.7%,24.6%²6.2%and 12.6%¹6.7%,respectively.（2）Integreted rice-duck farming significantly improved dissolved O2（DO）content,and increased floodwater N and P concents.Compared with R,RD increased floodwater DO content by 20.0%²2.0%,total N content by 81.1%¹01.1%,NH4⁺-N content by45.4%⁸0.0%,NO3^–-N content by 11.8%¹8.3%,and total P content by 32.7%⁴1.2%during the period of rice-duck co-culture.（3）Integreted rice-duck farming significantly reduced algal and protozoa biomass,and decreased algal diversity.Compared with R,RD significantly decresed the species of Chlorophyta and Cyanophyta by 21.3%²6.7%and 29.9%³2.9%,the biomass of Bacillariophyta,Chlorophyta and Cyanophyta by 46.7%⁵2.9%,27.1%²9.0%and13.6%⁴7.1%,respectively,and thus reduced Simpson index by 11.6%²4.5%and Shannon index by 9.9%²1.3%.Moreover,the biomass of Protozoa,Rotifer,Cladocerans and Copepods under RD was markedly decreased 36.1%⁴8.2%and34.6%⁴1.0%relative to R,respectively.Correlation analysis indicated that the species and biomasses of Bacillariophyta,Chlorophyta,and Cyanophyta were significantly negatively related to several forms of N and P contents,and the species and biomasses of Euglenophyta were significantly positively correlated with several forms of N and P contents.（4）Integraed rice-duck farming significantly affected N2O and CH4 emissions,and GWP subsequently.RD significantly increased N2O emissions by 6.1¹5.5 fold,reduced CH4 emissions by 32.0%³2.7%,and thus GWP by 28.0%relative to R.Compared with R,RD increased rice gain yield by 2.7%³.6%,and thus decreased GHGI by41.3%⁴4.8%.Structural equation model anlysis indicated rice-duck system affected GHG emisisons by three paths.Firstly,the activities of ducks improve floodwater DO content and soil Eh due to controlled aquatic organism growth and improvement of exchange between the soil and the atmosphere.Secondly,the excretions of ducks enhance soil inorganic N content,which provides the substrates of nitrification.Thirdly,the activities of ducks eat the old and ill leaves of rice and control unproductive tillers,and promote rice growth.These three processes therefore affect N2O and CH4 emissions from the rice-duck system.（5）Economic and ecological benefits（EB）of different treatments showed that RD could increased economic benefits by 37.8%³9.2%,and net ecosystem economic benefits（NEEB）by 39.7%⁴0.8%.In summary,the integrated rice-duck farming can effectively increase available nutrient contents of soil and floodwater,improve soil oxidizability,and significantly mitigate CH4 emissions and GWPs.Moreover,the system can control weeds and aquatic organism growth,enhance rice grain yield,and thus increase economic and ecological benefits.Therefore,our results suggest that the farming is a key approach for realizing agricultural supply-side reform in China,and is also an important model of developing green agriculture and revitalizing rural areas.更多还原