Research Progress of Rice-Fish Integrated Farming

Rice-fish integrated farming （RFIF） can change the agricultural production pattern from mono-farming model to the co-farming model, and the stereoscopic and integrated farming system established by RFIF can change the flat production to the stereoscopic production. Therefore, RFIF is the important development direction for agriculture to change pattern and adjust structure. In order to further promote development of the research and application of RFIF, the general development situation of RFIF in China was reviewed; the effects of RFIF on increasing farmer income and enhancing agricultural efficiency were clarified. The technologies matched with RFIF, such as rice paddy engineering technology, safe plant protection technology, security fertilization technology, fish disease prevention and control technology and water quality management technology, were summarized, and the supporting role of RFIF for agriculture was pointed out. In addition, the development prospect of RFIF was proposed, as well as the key research direction of RFIF.

Development of an Integrated Tool for Small-Scale Maize Farming in Uganda

About 62% of the maize produced in developing countries is cultivated manually owing to limited access to appropriate technology. Available technologies perform a single operation, necessitating farmers to buy multiple implements, which is expensive. In this study, an ox-drawn tool integrating a plough, planter and cultivator for small-scale maize farming was developed and its performance evaluated. Planting and cultivating units were designed and fabricated for assembly onto an existing standard ox-plough beam. The integrated tool was tested in the field to assess the effectiveness and efficiency of cultivation and planting of maize. Results showed that the planting unit had an average seed rate of 35.4 kg/ha with a seed damage of 4% and an effective field capacity of 0.15 ha/h at a field efficiency of 87.3%. The cultivating unit had an effective field capacity of 0.1 ha/h and a weeding efficiency of 86%. The efficiency, effectiveness and reliability for field operations are superior to manual operations currently used by farmers and are comparable to single-unit prototypes developed in other countries. This demonstrates the technical feasibility of integrating planting and cultivation units onto an existing mould board plough instead of buying multiple tools.

Influencing Factors on Rice Sheath Blight Epidemics in Integrated Rice-Duck System

Sheath blight, a disease caused by the fungus Rhizoctonia solani Kuhn （anamorph）, has been the most economically significant disease of rice. It was frequently reported that the disease was well-controlled in integrated rice-duck system without the employment of fungicides. However, the effecting factors behind this phenomenon were rarely reported. In this research, experiment was carried out between two treatments, rice combined with ducks （RD） and conventional rice field without ducks rearing （CK） in early season rice paddy, to investigate the variations of sclerotia in floodwater and on rice plant, microclimate 10 cm above the waterline in rice paddy and activity of protective enzymes in rice plants. The results showed that the floating sclerotia in floodwater in RD was 86-91% lower than that in CK, and adhering sclerotia in rice plant in RD was 67-78% lower than that in CK. The relative humidity tested significantly lower and light intensity tested significantly higher in RD. The temperature in the early rice growth stages in RD was slightly lower than that in CK, but it was significantly higher （32.3-36.5~C） in the middle stage rice growth stages. The polyphenoloxidase （PPO） activity in RD were lower than that in CK, but the enhanced activity of phenylalanine ammonia-lyase （PAL）, peroxidase （POD） and Chitinase was observed in different stages of rice growth in RD, especially the Chitinase which showed higher activity in all investigating days.

Dynamic Emission of CH₄from a Rice-Duck Farming Ecosystem

Global climatic change induced by emissions of greenhouse gases from human activities is an issue of increasing in-ternational environmental concerns, and agricultural practices and managements are the important contributors for such emissions. This study investigated dynamic emission of methane (CH4) from a paddy field in a rice-duck farming ecosystem. Three different cultivation treatments, namely the organic fertilizer + duck (OF+D), chemical fertilizer + duck (CF + D), and chemical fertilizer (Control) treatments, were employed in this study. Experimental data showed that hourly variations of CH4 emission from the paddy field during the day were somewhat positively correlated (R2 = 0.7 for the OF + D treatment and R2 = 0.6 for the CF+D treatment) to the hourly changes in air temperatures in addi-tion to the influences of the duck activities. The rate of CH4 emission for the CF+D treatment was higher than that of the Control treatment at the tillering stage, whereas the opposite was true at the heading stage. In contrary, the rate of CH4 emission for the OF + D treatment was always higher than that of the Control treatment regardless the tillering or heading stage. Our study revealed that the rate of CH4 emission depended not only on air temperature but also on the rice growth stage. A 6.7% increase in CH4 emission and in global warming potential (GWP) was observed for the CF + D treatment as compared to the Control treatment. This study suggested that although the impacts of duckling on the emission of CH4 depended on the rice growth stage and air temperature regime, the introduction of ducks into the rice farming system in general mitigated the overall CH4 emission and thereby the GWP.

Transient Stability Study of Power System with Large-Scale Wind Farm Integration

Large-scale wind power integration has become the current development trend of the power system. Large-scale wind power integration can change the original structure and characteristics of the system. Thus, it’s necessary to analyse the transient stability of power system which contains wind power, and to study the controlling strategy for improving the transient stability of power system. Based on EEAC, this paper studies the transient stability of the power system which contains wind power system theoretically, proposes the calculation method for accelerating area, decelerating area and margin, and illustrates the impact of wind power integration on the transient stability with power angle curve. Furthermore, this paper studies the modeling and simulation, and the experimental results prove the correctness of the theories.

Empirical Study on the Benefit Increase of New Contract Farming 1+3+X Model

For a long time,the development model of traditional rice planting industry has been single,linear,and focusing on production first and then market.However,with the low price of rice,such problems as slow technological upgrading,meager profits,and unstable rice quality in the primary industry planting units and farmers have become increasingly prominent.The integration and development of the rural primary,secondary,and tertiary industries and industrial integration have the same root.They are integrated industrial development based on technological or model innovation,vertical and horizontal integration.Three agricultural leading companies(Nanjing Tianwei Agricultural Technology Co.,Ltd.,Nanjing CHYKINGYOUNG Biological Technology Co.,Ltd.,and Jiangsu Jingshan Eco-organic Agriculture Co.,Ltd.)established an industrialization complex,and used their respective technical,operational,and market advantages to integrate and form a rice contract farming 1+3+X model.This model effectively integrates scattered rice planting,rice processing,and rice sales in Nanjing City of Jiangsu Province,and Chuzhou City of Anhui Province,and unifies planting regulations and supply of production materials,safeguards the supply of green and high-quality rice and realizes high quality and high price.In addition,it integrates farmers into the entire industrial chain of contract farming,summons up the production enthusiasm of farmers and greatly increases their income from planting production.

乡村振兴背景下栽培与耕作学教学改革与探索

栽培与耕作学是涉农专业的核心课程之一,在乡村振兴背景下,其对农业人才的培养具有重要作用。该文以贵州师范学院为例,对栽培与耕作学课程的历史沿革进行介绍,对课程教学现状以及存在的问题进行探讨分析,从课程思政、课程内容、教学评价和教学方法等方面提出一些建议,以期为高质量课程的建设提供参考。

风电场参与电网调频的多机协同控制策略

【目的】考虑风电场中不同风况下风电机组参与一次调频能力的差异,在下垂控制和惯量控制策略的基础上,对机组的调频能力评估方法进行优化。【方法】提出了一种改进的多机组调频参考功率协同控制策略。【结果】引入多机组协同控制方法能够有效改善机组之间调频参考功率的分配,从而有效调节各机组参与系统一次调频的程度。在惯量控制和下垂控制的基础上引入改进的协同控制策略,依据机组在实际风况下运行的状态,评估机组能够有效参与一次调频的参考功率。引入调频能力系数能够实现调频功率参考值在各机组之间按能分配。【结论】协同控制策略能够有效保护风电机组转速,同时能够有效改善电网频率响应。

家庭农场创业资源整合驱动因素与作用机理研究——基于扎根理论和SEM模型的融合方法

我国现有家庭农场尚处于起步阶段,因受自身弱质性、创业资源匮乏、创业环境复杂性等因素制约而面临着巨大挑战。文章基于相关文献将家庭农场创业资源整合过程界定为识别、获取、配置和运用,使用扎根理论方法分析30个家庭农场资源整合案例,形成创业资源、内在需求、整合意愿、农场主个性特征、创业环境和家庭农场创业资源整合6个维度理论构想,建立驱动因素模型。依据分析结果,借鉴相关测量量表开发创业资源整合驱动因素量表,验证量表信效度并利用结构方程模型对建构的理论模型进行实证检验。结果表明,创业资源和整合意愿直接驱动家庭农场进行创业资源整合,内在需求经由整合意愿驱动家庭农场进行创业资源整合,农场主个性特征和创业环境在内在需求与整合意愿关系中起调节作用。通过拓宽创业资源整合的研究外延,丰富家庭农场创业问题的理论与方法体系,为家庭农场破解资源约束困境提供了新思路。

面向乡村振兴的农业技术应用与推广型人才培养体系构建与实践--以山东农业大学为例

全面推进乡村振兴,实现农业农村现代化,关键在科技、在人才。山东农业大学构建的农业技术应用与推广型人才培养体系,在人才培养实践中坚持“学生中心、需求导向、协同育人”培养理念,采用厚植情怀、耕读合一和协同育人等人才培养路径,创建“四课融通、‘四层次’实践、三位导师、三联合”育人模式。经过五年实践,培养一批“下得去、用得上、留得住、干得好”的农业技术应用与推广型人才,在破解乡村振兴人才瓶颈问题方面呈现出良好的发展局面。

长江流域2种水产养殖模式的生命周期环境影响评价

本研究以长江流域内的池塘养殖和稻渔综合种养2种水产养殖模式为对象,应用生命周期评价方法,分析2种养殖模式对能源消耗(EU)、全球变暖潜势(GWP)、酸化潜势(AP)、富营养化潜势(EP)以及水资源消耗(WU)5种环境指标的影响,并探究2种主要输入因子(饲料和电力供应)和养殖过程对各环境指标的影响,从而评价2种养殖模式对环境影响的差异。生命周期评价结果标准化处理和加权评估显示,稻渔综合种养模式的WU、EP、GWP、AP和EU值分别为11.650、0.770、0.141、0.096和0.003,总环境影响指数(TEII)为12.660;池塘养殖模式的WU、EP、GWP、AP和EU值分别为31.453、1.187、0.210、0.174和0.007,TEII为33.031。与稻渔综合种养模式相比,池塘养殖模式的各项环境指标均较高。对环境影响的贡献率分析表明,饲料供应对EU、GWP和AP的贡献率最高,EP主要受饲料供应和养殖过程的共同影响,而WU主要集中在养殖过程中,电力供应主要影响EU、GWP和AP。生命周期评价的结果表明,与池塘养殖模式相比,稻渔综合种养模式显示出更友好的环境效益,在我国长江流域具有较大的发展空间。2种养殖模式的贡献率分析表明,改进饲料生产工艺、建立精准投喂技术、应用先进的尾水处理技术和适当提高养殖密度是我国长江流域水产养殖环境友好生产的关键。

生态种养技术采纳能否提升农户社会资本?——以稻虾生态种养技术为例

生态种养技术的经济和生态功能一直备受关注,但社会功能却一定程度上被忽视。为探究生态种养技术的社会功能,本文基于湖北省江汉平原地区1039份稻虾生态种养农户的调研数据,采用处理效应模型,分析并检验了生态种养技术采纳行为对农户社会资本水平的提升作用。结果表明:1)稻虾生态种养技术的社会功能十分突出,稻虾生态种养技术采纳行为对农户社会资本存在显著的提升效应。农户采纳稻虾生态种养技术后社会资本总量水平会提升0.047个单位,其中社会网络规模将扩大114.266个单位,而社会网络地位则降低了3.595个单位。2)从影响机制来看,合作社参与和互联网使用是稻虾生态种养技术采纳行为提升农户社会资本的重要途径。3)从异质性分析来看,稻虾生态种养技术采纳行为对农户社会资本的提升效应存在收入和年龄异质性,稻虾生态种养技术采纳行为对高收入和60岁以下农户的社会资本提升效应更为明显。因此,要全面地认识和客观地评价稻虾生态种养技术的社会功能,进而促进农户社会资本积累。

大豆—玉米带状复合种植耕种机械化研究进展

为充分发挥大豆—玉米带状复合立体化种植技术优势,保证我国粮油安全,解决作物争地矛盾,配套的复合耕种机械化研究成为首要环节。从国内典型多种植模式出发,总结地区间套作技术下大豆—玉米配套耕种机械特点,围绕耕种机具整地、洁茬、施肥、排种、播深及投种等作业阶段,阐述对比耕种机械技术工作原理,发现实际生产中仍存在秸秆拥堵、种肥排量和位置不协同、播深变异系数大和投种着床不均匀等问题,从农机农艺融合方面提出轻扰低耗洁茬、处方分层施肥、种肥电驱变量控制、多传感智能仿形播种、种粒平稳着床等一系列改良大豆—玉米复合耕种机械的路径,以期促进绿色高效发展。

基于模型数据混合驱动的大规模双馈风电场并网数字孪生建模

当前双馈风机详细模型具有多时间尺度动态和复杂控制环节,导致建模困难、大规模双馈风电场并网详细仿真建模所需算力庞大的问题。实际风机并网外特性无法实时反馈到仿真系统中,同时风电场功率输出受到多方面如风速、风向、老化等影响,使仿真系统无法精确拟合真实电力系统。针对这一问题,该文构建大规模数字孪生双馈风电场并网的电力系统模数混合驱动模型,实现了风机与电网互动反馈的实时更新,降低了算力需求,同时与风机物理实体实时匹配的虚拟模型具备较高的输出精度,满足精细化仿真需求。文中每台双馈风机采用长短期记忆网络构建数据驱动模型,风电场架构及所并电网选取常用的物理仿真模型,以数字孪生技术实现风机物理模型维护、虚拟数据模型更新的双向反馈。算例通过真实量测数据测试,结果表明在不同工况下该双馈风电场并网数字孪生模型较传统模型具备更优秀的拟合能力与精准度,同时实现了虚拟模型的实时更新能力。该模型有助于在大规模风电场并网中探寻具体某台风机故障、控制方式变化、风速波动等情况,研究风机之间相互影响、电网出现扰动时对风电场的影响。

农旅融合、要素流动与县域经济增长

农旅融合是践行“绿水青山就是金山银山”理念的良好载体和生动实践。在理论分析和模型推演的基础上,利用休闲农业与乡村旅游示范县政策设计准自然实验,并基于2008-2019年中国1778个县域的面板数据,采用多时点双重差分模型,考察农旅融合发展对县域经济增长的影响。结果表明,农旅融合发展对县域经济增长具有显著的推动作用。该结论在经过平行趋势检验、反事实检验等多重稳健性检验后依旧成立。机制分析表明,农旅融合发展主要是通过吸引资本流入、加快非农转移和推动技术进步来提高县域经济发展水平,进一步凸显出要素流动在县域经济增长过程中的传导作用。此外,从资源禀赋看,农旅融合经济增长效应的发挥,不仅依赖于县域内部旅游生态资源,对外部交通条件等基础设施也有较高要求。同时,东部地区县域的农旅融合发展能发挥出更明显的经济增长效应。可见,基于本地资源优势推进农旅融合发展,并进一步补齐县域交通等基础设施建设短板,是推动县域经济增长的重要选项。

风电场配套储能的自适应虚拟惯性——阻尼控制

提出了一种面向风储系统并网点频率稳定性提升的储能自适应虚拟惯性-阻尼控制策略。首先,通过分析推导,在储能控制策略中引入惯量控制参数与阻尼控制参数的调整系数,实现控制参数的自适应调整;其次,通过小信号分析整定,给出惯量控制参数与阻尼控制参数的取值范围;最后,基于所搭建的风储联合系统,对本文所提控制方法面对不同类型故障时的有效性进行了验证。结果证明,相比于传统虚拟同步控制方法,本文所提方法能够显著提升并网点频率稳定性,并且实现惯性和阻尼的自适应平滑调节。

Social and Economic Considerations for Creating Sustainable Climate Change Haven Communities

As Climate Change Haven Communities are constructed across the Northern Hemisphere, it will be necessary to attract two types of migrants to populate them. The first group consists of professionals and companies in eco-sustainable businesses, such as law firms, insurance companies, investment firms, banking, technological innovation, mass media, medical research and pharmaceutical research. The second group will consist of persons engaged in organic/eco-sustainable agriculture whose crops and animal husbandry practices can be transferred successfully to Climate Change Haven regions. The present research focuses on the social and economic variables that must be taken into account to insure that each new Climate Change Haven Community becomes successfully integrated with the local population and forms a cohesive, harmonious social structure. Examples are given from the United States, France, Spain, Portugal and Italy.

考虑尾流效应的风电场分群综合惯性控制研究

为解决尾流效应导致风电场风速分布不均匀、风电场单机等值模型不能进行精准综合惯性控制的问题,提出一种风电场分群综合惯性控制策略。该策略以具备相近调频能力为机组分群原则,定义调频能力因子作为分群指标,通过聚类算法对机组进行动态分群;综合惯性控制环建立以系统频率偏差量、系统频率变化率为输入,惯性控制比例系数、惯性控制微分系数为输出的模糊自适应综合惯性控制器,进而实现风电场分群综合惯性控制。仿真结果表明,所提出的分群指标是有效的,建立的风电场多机等值模型较准确地体现了各机组群的调频能力,且建立的风电场分群综合惯性控制策略可以提供更为可靠的惯性支撑。

Integrated Equivalent Model of Permanent Magnet Synchronous Generator Based Wind Turbine for Large-scale Offshore Wind Farm Simulation

The high-speed simulation of large-scale offshore wind farms(OWFs) preserving the internal machine information has become a huge challenge due to the large wind turbine(WT) count and microsecond-range time step. Hence, it is undoable to investigate the internal node information of the OWF in the electro-magnetic transient(EMT) programs. To fill this gap,this paper presents an equivalent modeling method for largescale OWF, whose accuracy and efficiency are guaranteed by integrating the individual devices of permanent magnet synchronous generator(PMSG) based WT. The node-elimination algorithm is used while the internal machine information is recursively updated. Unlike the existing aggregation methods, the developed EMT model can reflect the characteristics of each WT under different wind speeds and WT parameters without modifying the codes. The access to each WT controller is preserved so that the time-varying dynamics of all the WTs could be simulated. Comparisons of the proposed model with the detailed model in PSCAD/EMTDC have shown very high precision and high efficiency. The proposed modeling procedures can be used as reference for other types of WTs once the structures and parameters are given.

乡村振兴视域下农耕文化复兴路径研究——以湖州荻港桑基鱼塘为例

农耕文化作为中华文化之母,拥有悠长的历史,是人类文明不断向前发展演变的重要因素和基础。该文将基于乡村振兴战略背景,对如何让传统农耕文化焕新发展并赋能乡村振兴进行研究。在城市化、工业化不断发展的当下,透过传统农耕文化所面临的传承、认同、没落等方面的生存困境,剖析其与乡村振兴的内在关联,并以湖州荻港桑基鱼塘作为具体研究对象,窥探并总结传统农耕文化的传承与发展,为研究乡村文化振兴提供历史经验。该文分别从文化内在塑造文化场域、特色文化产业链形成融合布局开发及多方聚合协同治理3方面切入,探寻乡村振兴视野下农耕文化的复兴路径,为农耕生存空间扩容。