【作者】 杨勇；

【导师】 张洪程； 戴其根；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2004， 博士

【摘要】 稻渔共作是水稻种植与蟹、虾、鱼等水生经济动物养殖二者互利共作的复合生态农业模式。自20世纪90年代以来，稻渔共作面积在我国急剧上升，已成为农业产业结构调整中倍受关注的重点之一。但同我国大多数生态农业的发展一样，稻渔共作虽有生产实践方面先进的优势，但绝大部分仍停留在生产经验的水平上，缺少规律性的认识，生产技术的科学化、规范化程度不高，生产的水稻与水产品品质不优，产量不稳，不利于技术与生产成果的巩固和进一步发展。因此，加强稻渔共作生态农业体系的科学试验与系统研究，建立安全优质高效的生产理论与技术体系成为当前稻、渔工作者迫切需要解决的重要课题。为此，本研究在长江下游稻渔共作分布最集中、面积最大的江苏里下河稻区(兴化市)稻渔共作生产现状调查的基础上，分别就稻渔共作生态系统中的生态环境、水稻、蟹(虾、鱼等)三方面要素的特征与相关技术进行系统研究，提出稻渔共作优化同步模式并进行技术效益评价，初步制订稻渔共作安全优质高效生产技术规范。主要的研究结果如下： (1)稻渔共作生态系统与常规稻田生态系统及养殖池塘生态系统相比，在系统结构与功能、水、土理化性状、物流能流特征方面被揭示并阐明的生态特征如下：系统空间水平结构与垂直结构上生态位呈现多样性，形成了由稻畦面向畦面沟、围沟、暂养沟不断加深的水体环境，为蟹、虾等提供了生长与栖息的多种生境，稻田内生物种类更趋丰富；系统内物流、能流途径增加，食物链得到加环而趋于复杂，可实现多层多级地充分利用各种资源，提高稻田资源的利用率；与常规稻田相比，稻畦面土壤容重降低，土壤饱和含水量、田间最大持水量和孔隙度增加，土壤的物理性状得到改善，但也存在着土壤氧化还原电位下降，随稻渔共作年限增加，土壤物理性状的改善作用逐步削弱等问题；与常规稻田相比，稻畦面土壤有机质及氨磷钾养分提高，土壤的肥力性状改善，且随稻渔共作年限的增加有进一步改善的趋势，共作期间土壤氮磷钾速效养分供应好于常规稻田；系统内水温杨勇，稻渔共作生态特征与安全优质高效生产技术研究存在季节、昼夜、水平及垂直方向的变化，畦面沟与稻畦面表层水温低于围沟，底层略高于围沟或相近，暂养沟与围沟中水温具有明显的垂直变化，白天变幅大，夜间变幅小，畦面沟与稻畦面水温垂直变化不明显，共作期间稻畦面水温较常规稻田变化缓和且昼夜温差小;系统水体溶解氧含量受太阳辐射与水生植物光合放氧影响较大，稻畦面表水层由于受光不足，浮游生物光合放氧弱，溶解氧含量显著低于围沟等裸水面，但底水层则较围沟等为高，系统各生境中水体溶解氧垂直变化明显，水层越深含量越低，以1小16时为最高，垂直变幅明显，凌晨日出前较低，垂直变化小;系统内水体pH值全天中有明显波动，凌晨最低，16时左右最高，稻畦面低于围沟;与常规稻麦两熟模式相比，系统有机能的投入比例大，投能结构合理，能量产投比高，系统稳定性和自我维持能力强;与常规稻麦两熟模式相比，系统养分投入产出较为平衡，养分保蓄的生物学机制得到加强，养分在系统内部得到多级利用，再循环比例增加，并有利于稻田和周边生态环境保护。 (2)以同期播种的常规栽培水稻为对照，对稻渔共作生态系统中栽培的半深水稻进行了比较研究。结果表明，自分孽盛期直至水稻收获前7一10天处在20科ocm深度水层的水稻，被揭示并阐明的生态特征如下:稻渔共作具有延长水稻生育期，增加群体各生育期生物量，提高叶面积指数和冠层叶片的面积马延缓后期功能叶片衰老，增大茎秆粗度，增加氮素吸收，促进根系发育及伸长节上须根发生等特点。但同时也表现出稻株基部节间长度增大，节间数增多，植株重心上移，后期根系活力降低等特征。在产量及其结构方面表现为茎孽成穗率、穗粒数、结实率下降，粒重增加，若品种选择与栽培控制得当，可提高单位面积有效穗数并达到增产的目的。稻米品质性状上一致表现为加工品质、外观品质与营养品质均有所改善。 (3)研究对稻渔共作水稻栽培中稻作方式、水稻品种、播栽期、种植密度、施肥技术、稻田病虫草发生与防治技术六个方面的关键生产技术进行了攻关。①稻作方式:与移栽稻相比，同期播种条件下，直播稻各主要生育期前移，全生育期缩短;高峰苗多但茎孽成穗率低，最终穗数减少，早直播出苗率及茎萦成穗率高于水直播;根数多且粗，干物重高，但地上部氮素积累量减少;产量构成中穗数下降，穗粒数减少，结实率与千粒重增加，最终产量下降;稻米加工品质、外观品质下降。②水稻品种:综合稻渔共作生产对水稻品种在生育期、个、群体特征、抗病性、产量及品质等多方面的要求，从28个不同类型品种中筛选出86优8号、常优1号、华粳3号、武香粳14号4个综合评介较优的偏迟熟粳稻品种。③播栽期:稻渔共作水稻播栽期适当提前可显著增加水稻全生育期与稻蟹共生期，利用前期稻田生产条件发足分桑，增加干物质积累量，形成足够的穗数，增加冠层功扬州大学博士学位论文能叶面积和株高以适应深水层生态，达到增产与改善稻米品质的目的;早播会加重水稻条纹叶枯病发生，?更多还原

【Abstract】 Rice-fish culture is a complex ecological agriculture mode which combines the culture of rice with culture of economic aquatic such as crabs, shrimps, fish, etc. Since 1990s, the rice-fish culture area has risen rapidly, and it has become an important part in the adjustment of agriculture industrial structure. As the development of other ecological agriculture hi China, although there were some advantages in production practice of rice-fish culture, most were still based on production experimence, it was still lack of normalized knowledge. The degree of scientific production and standardization was still lower. The quality of rice and aquatic products was not good and the production was not stable, which was not favorable to the further strengthening and development of technique and production. Therefore, to strengthen the scientific experiment and systematic study of eco-agricultural system in rice-fish culture and to set up theoretical and technique system for safe, good-quality, high-benefit rice-fish culture were becoming an urgent and important subject for the rice and fish researchers. Based on the survey of rice-fish culture status in Jiangsu Lixiahe area (Xinhua) where the rice-fish culture was the most concentrated and the biggest culture area, this research studied the characteristics and related technique system of the ecological environment, rice, crabs (shrimps, fish, etc.) in rice-fish culture. It put forward the optimized synchronizing mode for rice-fish culture. The technique benefit was also assessed and a preliminary criterion for safe, good-quality, high-benefit rice-fish culture has been set up. The main results were showed as follows:1. Compared with the conventional ecosystem in paddyfield and fishpond, the rice-fish ecosystem has the following ecological characteristics in systematic structure and function, physical and chemical property of water and soil, substance flow energy, etc.: the system showed the ecological diversity in horizontal and vertical structure, formed the water environment from rice farmland, deep down to farmland channel, surrounding channels and temporary channels. So that it provided crabs and shrimpswith the diverse ecological environment of growth and habitat, and the biological species were more abundant. The flow pathway of substance and energy increased and the food chain was strengthened toward more complexity. The resources could be fully used on different levels so that the efficiency of resources utilization was increased. Compared with the conventional paddyfield, the bulk density of rice farmland soil decreased, the soil saturation water content, field maximum holding water content and porosity increased, and the soil physical property improved. However, the soil redox potential could reduce, the alleviation of soil physical properties would be weaker with the year extension of rice-fish culture.The organic content and Nitrogen, Phosphorus, Potassium content rised, the soil fertility improved, and the alleviation effects could increase further with the extension of rice-fish culture. The supply of available N, P, K was better than that in the conventional paddyfield. The water temperature in the system varied with the season, diurnal and the vertical direction. The surface water temperature in farmland channels and rice farmland was lower than that in surrounding channels, it was a bit higher or close to that in the bottom level, and there was obvious vertical change in temporary and surrounding channels. The change was large during the day but small during the night, and it was not obvious in farmland channels and rice farmland channels. During the period of rice-fish culture, the temperature change hi rice-fish paddyfield was smaller than that in conventional paddyfield. The dissolved oxygen content in ecosystem was greatly influenced by solar radiation and oxygen generated by hydrophyte. Because of the weak sunlight and not much oxygen from plankton in the subsurface, it was significantly lower than that in surrounding channels, while hi deep water lay更多还原