Remote Monitoring of Expansion of Aquaculture Ponds Along Coastal Region of the Yellow River Delta from 1983 to 2015

Aquaculture ponds are one of the fastest-growing land use types in valuable and fertile coastal areas and have caused serious environmental problems. Quantitative assessment of the extent, spatial distribution, and dynamics of aquaculture ponds is of utmost importance for sustainable economic development and scientific management of land and water resources in the coastal area. An object-oriented classification approach was applied to Landsat images acquired over three decades to investigate the long-term change of aquaculture ponds in the coastal region of the Yellow River Delta. The results indicated that the aquaculture ponds in the study area undergone a sharp expansion from 40.38 km^2 in 1983 to 1406.89 km^2 in 2015, and the fast expansion occurred during the period of 2010–2015 and 1990–2000. Natural wetlands, especially mudflat, and cropland were main land use types contributing to the increase of aquaculture ponds. The patches of aquaculture ponds were consequently prevalence in the north of the Yellow River Estuary and landscape metrics indicated an increase of the aquaculture ponds of the study area in the quantity and complexity. The expansion of aquaculture ponds inevitably had negative effects on the coastal environment, including loss of natural wetlands, water pollution and land subsidence, etc. The results from this study provide baseline data and valuable information for efficiently planning and managing aquaculture practices and for effectively implementing adequate regulations and protection measures.

Efficiency Pattern and Spatial Strategy of Ports in Yangtze River Delta Region

This paper measures the efficiency of ports in the Yangtze River Delta Region(YRDR) in 2008 and 2013 using port berth quantity, quay length, and human resources as input indicators, using cargo and container throughput as output indicators, and considering traditional(foreign trade dependence and industrialization level) and modern environmental factors(traffic line density, financial development level, and informatization level). To achieve such aim, this study constructs a multi-stage data envelopment analysis model(DEA) that identifies effective port decision-making units(DMUs) and generates a highly accurate conclusion by eliminating the interference from the exogenous environment and random errors. First, the external environment significantly affects port efficiency, with the traditional environmental factors showing huge fluctuations and the modern environmental factors producing great benefits. Second, the efficiency of ports in YRDR has increased from 2008 to 2013 primarily because of their pure technical efficiency. Third, the weighted standard deviation ellipse(SDE) analysis results reveal that the efficiency pattern of ports significantly deviates from their throughput pattern, while the center of SDE of port efficiency moves from the eastern coastal regions to the northwest regions. Based on these findings, this paper proposes spatial development strategies for YRDR, such as creating an unblocked environment where spatial elements can freely circulate, intensifying port-city joint development, implementing differentiated policies, and focusing on the spatial collaboration of port efficiency.

Critical effects on the photosynthetic efficiency and stem sap flow of poplar in the Yellow River Delta in response to soil water

To explore the critical relationships of photosynthetic efficiency and stem sap flow to soil moisture,two-year-old poplar saplings were selected and a packaged stem sap flow gauge,based on the stem-heat balance method,and a CIRAS-2 portable photosynthesis system were used.The results show that photosynthetic rates(P_(n)),transpiration rates(T_(r)),instantaneous water use efficiency(WUE)and the stem sap flow increased initially and then decreased with decreasing soil water,but their critical values were different.The turning point of relative soil water content(W_(r))from stomatal limitation to nonstomatal limitation of P_(n)was 42%,and the water compensation point of P_(n)was 13%.Water saturation points of P_(n)and T_(r)were 64%and 56%,respectively,and the WUE was 71%.With increasing soil water,the apparent quantum yield(AQY),light saturation point(LSP)and maximum net photosynthetic rate(P_(n)max)increased first and then decreased,while the light compensation point(LCP)decreased first and then increased.When W_(r)was 64%,LCP reached a lower value of 30.7µmol m^(-2)s^(-1),and AQY a higher value of 0.044,indicating that poplar had a strong ability to utilize weak light.When W_(r)was 74%,LSP reached its highest point at 1138.3µmol·m^(-2)s^(-1),indicating that poplar had the widest light ecological amplitude and the highest light utilization efficiency.Stem sap flow and daily sap flow reached the highest value(1679.7 g d^(-1))at W_(r)values of 56%and 64%,respectively,and then declined with increasing or decreasing W_(r),indicating that soil moisture significantly affected the transpiration water-consumption of poplar.Soil water was divided into six threshold grades by critical values to maintain photosynthetic efficiency at different levels,and a W_(r)of 64-71%was classified to be at the level of high productivity and high efficiency.In this range,poplar had high photosynthetic capacity and efficient physiological characteristics for water consumption.The saplings had characteristics of water tolerance and were not drought resistant.Full attention should be given to the soil water environment in the Yellow River Delta when planting Populus.

Study on High-efficiency Ecological Agricultural Development Based on Science and Technology in the Yellow River Delta

Based on the analysis of the status, characteristics and technological functions of high-efficiency ecological agricultural development in the Yellow river delta, the paper pointed out technological bottlenecks of the high-efficiency ecological agricultural development in the Yellow river delta. Some suggestions were proposed including changing the development concept, implementing nine projects, increasing capital investment, focusing on demonstration, and strengthening human resources.

Study on Land Use Changes in the Yellow River Delta from 1980 to 2010

Taking the Yellow River Delta for example, this paper applied remote sensing and GIS to explore land use changes in the local area from 1980 to 2010. The results showed that arable land, and urban and rural construction land were major land use types in the Yellow River Delta, unused land also took a large ratio; land use changes occurred mainly in coastal regions, in terms of change matrix, 25.46% of the grassland was reclaimed as arable land, unused land also witnessed great changes, specifi cally, 11.14% turned to arable land, 23.25% to construction land. This study provided references for the land use planning and development of the local area.

考虑生态耗水的干旱区绿洲灌溉用水效率评价指标与方法

针对现行干旱区绿洲尺度灌溉用水效率评价对生态服务效益考虑不足的问题,提出了在绿洲尺度上考虑生态耗水的灌溉用水效率评价指标和方法,并应用于宁夏引黄灌溉绿洲。结果表明:宁夏引黄灌溉绿洲农田蒸散消耗水量中的灌溉水量平均占比达74.7%,生态系统蒸散消耗水量中的灌溉水量平均占比达39.8%,灌溉水对生态系统的支撑作用显著;考虑生态耗水前后的灌溉用水效率差为0.052~0.074,占未考虑生态耗水灌溉用水效率的13.9%~16.1%,灌溉水的生态服务效益明显;提出的评价指标与方法合理可行,能客观反映干旱区灌溉用水的综合效益。

铁路网络联系对城市土地绿色利用效率的影响研究——以长三角地区为例

研究目的:探究铁路网络联系对城市土地绿色利用效率的影响及空间溢出效应,为依托铁路交通发展促进土地绿色利用效率提升提供科学依据。研究方法:超效率SBM模型,社会网络分析方法,空间面板模型。研究结果:(1)长三角城市铁路联系强度和土地绿色利用效率均呈现显著的增长趋势,土地绿色利用效率存在着较为明显的区域差异。(2)铁路联系强度的提高促进了本城市土地绿色利用效率的提升,与综合铁路联系相比,高铁联系对本城市土地绿色利用效率的提升作用更加明显。(3)铁路联系的加强促进了本城市产业结构合理化水平的提升和创新产出的增长,进而对土地绿色利用效率产生影响。高铁联系在促进本城市产业结构合理化水平提升和创新产出增长方面的作用更加明显。(4)城市对外铁路联系强度的提高产生了负向的空间溢出效应,抑制了邻近城市土地绿色利用效率的提升。研究结论:应充分发挥铁路建设在优化产业结构、促进创新方面的作用,依托铁路网络加强区域内经济技术合作、发挥各城市比较优势,以推动区域土地绿色利用效率的整体性提升。

基于Meta分析的黄河三角洲玉米产量及肥效特征

为解析黄河三角洲玉米产量分布及施肥效应,指导玉米合理高效施肥,分析2010—2020年黄河三角洲的143组玉米田间肥料试验,对不同扇面区域的玉米产量分布以及肥料利用率、产量差贡献率、相对产量、农学效率和偏生产力等进行统计和计算。结果表明,玉米平均产量6.81 t/hm^(2),不同扇面区域产量变幅较大,为2.63~9.52 t/hm^(2),第二扇面玉米产量显著低于第一、三扇面。施用氮、磷、钾肥的增产率均值分别为40.88%、8.49%、2.18%。基于Boundary line模型模拟的产量差为3.01 t/hm^(2),高产记录产量差为2.49 t/hm^(2),氮肥对产量差的贡献率最大,磷、钾肥次之。玉米氮、磷、钾肥的相对产量分别为0.76、0.99、1.05,氮肥农学效率、偏生产力分别为8.64、33.78 kg/kg,磷肥为2.85、86.12 kg/kg,钾肥为17.97、148.01 kg/kg。综上,氮为玉米产量的第一限制因子,施肥增产效果为氮肥>磷肥>钾肥。黄河三角洲玉米施肥管理中,应合理减施氮肥,配合土壤改良,以有效消减玉米产量差,达到增产节肥效果。

黄河九省(区)水资源绿色效率时空格局与影响因素研究

为探索黄河九省(区)水资源绿色效率,采用SBM-DEA模型和Tobit模型对黄河九省(区)99个地级市水资源绿色效率的时空分布及影响因素进行分析。研究结果表明:1)黄河九省(区)水资源绿色效率整体呈上升趋势,下游的中原城市群和山东半岛城市群水资源绿色效率较高,上游的兰西城市群和宁夏沿黄城市群相对较低;2)黄河九省(区)水资源绿色效率空间集聚分布显著,“高-高”型城市主要集聚在下游经济较发达的省份,水资源绿色效率呈显著的正向空间自相关,并存在集聚现象和溢出效应;3)第一产业和第三产业规模、水资源禀赋和节水水平对水资源绿色效率提升具有显著积极影响,外商直接投资对水资源绿色效率的影响较为消极。

黄河生态经济带玉米用水效率地区差异及空间收敛性分析——基于环境规制视角

基于环境规制视角,将碳排放、面源污染、灰水足迹等纳入超效率SBM模型对2011—2020年黄河生态经济带地级市玉米用水效率进行测度,并运用Dagum基尼系数和空间杜宾模型对其地区差异及空间收敛性进行分析。结果表明,样本期内总体玉米用水效率提升明显,技术进步是主要驱动力;区域总体及内部差距逐渐扩大,区域间差异变动具有一致性;具有显著的空间溢出效应和β收敛趋势,但相关变量收敛显著性影响存在异质性。基于此,为了从整体上进一步提高环境规制下黄河生态经济带玉米用水效率及优化其空间布局,提出了加强动态检测,落实节水细则,推动区域协同,开展综合整治,加大技术投入,引导多方协同的建议。

长三角地区工业细分行业碳效率评价及其影响因素分析

由浙江、江苏、安徽和上海组成的长三角地区是国内经济发展高地,同时也是高碳排放区域。研究长三角地区细分行业碳效率特征及其影响因素,不仅对这一地区实现低碳发展目标具有重要意义,也对全国其他地区未来低碳发展具有较为重要的指导意义。利用固定效应随机前沿模型对2014至2019年三省一市37个行业进行了碳效率测算,并对各地区工业碳效率动态变化进行了分析;然后,基于随机前沿模型方法对碳效率影响因素进行了探究;最后,应用不同生产函数形式和去极端值的方式验证了本模型的稳健性。研究结果表明,长三角地区三省一市的高碳效率行业存在明显差异,且主要受行业专业化程度以及环境规制强度的影响,国有资产占比对碳效率的影响在安徽省显著。此外,提高专业化程度是持续推动碳效率水平提高的关键性因素,环境规制能快速推动部分行业提高碳效率,但是无法推动地区工业碳效率的长期进步。

区域市场一体化是否提升了城市绿色发展效率?——基于长三角统一大市场的实证分析

区域市场一体化有利于统筹发挥有效市场和有为政府的积极互动作用,为协同推动区域绿色高质量发展提供有力支撑。文章基于全局生产前沿和非径向方向性距离函数构建DEA模型,测算了长三角全域41个地级以上城市全要素绿色发展效率,结果显示,长三角城市全要素绿色发展效率整体上呈上升趋势,其中,长三角中心区城市全要素绿色发展效率保持较快的持续上升趋势,外围区城市全要素绿色发展效率经历了一个先下降、再平缓上升、后较快上升的变化趋势。运用面板Tobit模型实证研究长三角商品市场一体化、资本市场一体化和劳动力市场一体化对城市全要素绿色发展效率的影响,研究结果表明,长三角市场一体化整体上有利于促进城市全要素绿色发展效率提升,尤其是资本市场一体化显著促进了城市全要素绿色发展效率提升,但商品市场一体化和劳动力市场一体化对城市全要素绿色发展效率的整体促进作用尚不显著,市场一体化对全要素绿色发展效率的影响效应在长三角中心区城市表现更为显著。今后要进一步发挥市场机制的主导作用,实现有效市场与有为政府有机结合,提升长三角市场一体化对城市绿色发展效率的促进作用,尤其是要加强商品市场一体化和劳动力市场一体化对城市全要素绿色发展效率的积极作用,提升市场一体化对长三角外围区城市全要素绿色发展效率的协同促进作用。

黄河流域数字经济产出效率测度及影响因素分析

基于2011—2021年黄河流域9省投入产出数据,测算了数字经济产出效率并进行了区域差异分析与动态评价,并建立面板回归模型探究全要素生产率的影响因素。研究结果表明:从产出效率来看,黄河流域数字经济产出综合技术效率均值为0.734,数字经济整体水平还有待提高,9个省中,青海、宁夏、内蒙古产出效率相对优于其他省份,分区域来看的话,黄河上游最高,黄河中游次之,黄河下游最低;从全要素生产率来看,黄河流域数字经济全要素生产率总体呈现震荡式波动,除了内蒙古,其余各省的全要素生产率没有得到提高,上游区域对黄河流域的数字经济产出效率发挥了积极的推动作用,黄河中、下游作用不明显;从影响因素来看,经济发展水平、政府科技投入强度、自主创新水平对黄河流域数字经济的全要素生产率具有正向影响,人力资本水平、城镇化水平、产业结构、对外依存度对全要素生产率产生了负向影响。

黄河下游地区基本公共服务投入效率时空分异及影响因素

基本公共服务投入效率对基本公共服务均等化及协调发展具有重要作用。本研究以黄河流域下游地区为案例区域,运用非期望产出超效率SBM模型、标准差椭圆模型、梯度提升树回归模型以及灰色GM(1,1)模型对基本公共服务投入效率的时空分异及其影响因素进行实证研究。结果表明:基本公共服务投入效率呈现出“东北—西南”格局,重心向东北偏移,其中山东段的评价值增长,而河南段下降;人口规模、产业经济和资源消耗是影响基本公共服务投入效率的主导要素,预测模型结果表明在未来时段多数地市的变化趋势比较平稳。

长三角地区绿色物流效率评价——基于超效率SBM模型与Malmquist-Luenberger指数分析

采用包含非期望产出的SBM模型、Malmquist-Luenberger指数和相关指标,对长三角2011—2021年的绿色物流效率进行静态和动态分析.结果显示:从总体看,长三角绿色物流效率水平虽然相对较高,但仍有进步空间;三省一市绿色物流效率的表现各不相同;Malmquist-Luenberger指数和分解表明,长三角绿色物流效率的改进主要源于物流的技术进步.基于上述结果给出相应的建议.

沿黄9省(区)工业绿色发展效率及其影响因素分析

工业绿色发展是黄河流域生态保护和高质量发展的重要体现.基于2011—2019年面板数据,采用Super-SBM模型和GML指数研究沿黄9省(区)工业绿色发展效率的时空演变规律,同时构建Tobit模型分析该区域工业绿色发展效率的影响因素.结果表明:研究期内,沿黄9省(区)工业绿色发展效率从2011年的0.7387提升至2019年的0.8053,虽出现波动,但整体呈上升态势,且工业绿色全要素生产率变动主要受技术进步与规模经济影响,尤其对青海、甘肃、宁夏、山西4省(区)效果最为显著;工业绿色发展效率空间分异明显,呈上游向下游递增格局,内蒙古和陕西2省(区)为稳定性高效率区域,而山西和宁夏2省(区)始终是典型低效率区域,总体来看,黄河上游地区是沿黄9省(区)工业绿色发展的薄弱地带;经济发展水平、人力资本、环境规制与科技创新对沿黄9省(区)工业绿色发展效率产生正向驱动作用,而城镇化、产业结构和对外开放则出现显著负向作用,其中环境规制对中、上游地区的影响效果不显著,城镇化水平和人力资本对中游地区的抑制作用有限,产业结构重化阻碍黄河上游地区绿色发展效率的提升,科技创新对黄河中游地区工业绿色发展效率产生明显负向影响.

Evolution of coordination degree of eco-economic system and early-warning in the Yangtze River Delta

On the basis of Landsat TM data of the Yangtze River Delta （YRD） Economic Zone in 1991, 2001 and 2008, this article, taking 90 counties in this region as study units, built spatial data transformation models, ecosystem service value （ESV） and coordination degree of eco-economic system （CDES） models. With the aid of ArcGIS9.3, mass grid and vector data has been processed for spatial analyses. ESV and CDES indexes have demonstrated the relationship between economic development and eco-environment system and its evolu- tion characteristics in the researched areas. Furthermore, the indexes have also been used for functional zoning and pattern recognition. Some results can be shown as follows. Firstly, since 1991, land use in the YRD has greatly changed： urban land area has increased primar- ily from original paddy land, dry land, grassland, garden plot and other land. Secondly, the ESV model has proved the deterioration trend of the YRD ecological system from 1991 to 2001 and slower degradation trend during 2001-2008. Also, it is illustrated that land-use conversion from water area and paddy field to urban area and dry land could cause great damage to ecosystem stabilization. Thirdly, GDP in the central and southern parts of the YRD is higher than that in the northern part since 1991. GDP growth rate in the central part is higher than that in the northern part during 1991-2001. This growth rate in the central part is also higher than that in the southern and northern parts of the YRD from 2001 to 2008. Fourthly, the YRD could be categorized into 12 types of subregions in terms of CDES index. According to its spatial characteristic of CDES index value in the study area, eco-economic conflict area with low CDES value which is located in the central part is surrounded by eco-coordinated areas with high CDES values. This illustrates a core-periphery spatial structure exists in the YRD. During 1991-2001, the CDES value implied the convergent de- terioration trend of eco-economic system in the study area; while it gradually stepped into coexistence of divergent deterioration and coordination during 2001-2008. Finally, this paper analyzed five subregions in the YRD, including initially degrading zone, initially coordinative zone, continuously degrading zone, coordination-declined.zone and coordination-promoted zone, based on eco-economic coordination and evolution patterns. And these subregions can be recognized and categorized by spatial transformation model.

黄河三角洲盐碱地作物生态高效生产策略与技术

针对黄河三角洲盐碱地作物生产存在的熟制单一、生态脆弱、农田周期性返盐和面源污染严重等突出问题,本文提出了盐碱地“分类施策、用养结合”的管理策略和作物生态高效生产技术。轻度盐碱地以发展粮油作物为主,坚持“种轮防返”策略,利用粮油作物与耐盐作物周期性轮作、粮油作物宽幅间作轮作,防止返盐,保持地力;中度盐碱地坚持“用养结合”策略,合理布局棉花、高粱、油葵、饲草、绿肥等耐盐作物,科学配置一熟、两熟及单作、间作、轮作等种植模式,采用轻简化机械化生态高效生产技术,实现用养结合;重度盐碱地立足“生态保护”,发展碱蓬、柽柳等盐生植物复合种植模式,覆盖地表、抑制返盐、保护生态。通过分类施策、用养结合,实现生态效益和经济效益协同提高,引领黄河三角洲盐碱地高效生态农业高质量发展。

长三角地区工业园区水资源高效利用的发展趋势与策略

针对长三角地区工业园区面临的水资源、水环境、水生态与碳排放的多重限制问题,认为工业园区的水资源高效利用是高质量发展的重要支撑,污水资源化利用是水资源高效利用的关键途径。基于工业园区水资源高效利用相关研究、实践和政策,结合综合统筹与系统优化原则,提出了以五级处理-五级回用体系为核心的工业园区水资源高效利用策略。基于“双碳”战略,提出了耦合污水回用、资源回收、节能增效与多能互补的工业园区水资源高效低碳利用思路,可推动园区节水减污降碳协同优化。提出未来长三角地区工业园区水资源利用应向“低碳化、区域化、集成化、智能化”的方向发展。

基于Super-SBM-DEA模型的区域物流效率评价与影响因素

【目的/意义】长江三角洲经济增长的区域性特征逐渐凸显,对区域经济发展与物流效率的相关性进行分析,促进二者良性循环发展,为长江三角洲区域经济发展提供理论参考和实践指引。【设计/方法】选取2011~2021年长江三角洲区域41个城市的相关数据,运用Super-SBM-DEA模型、Malmquist指数从静态和动态方面对长江三角洲区域41个城市物流效率进行研究,借助Tobit模型分析城市物流效率影响因素。【结论/发现】2011~2021年长江三角洲区域41个城市整体物流效率较高,效率平均值在1左右徘徊;该区域全要素生产率增长的主要贡献来源于规模效率,其次是纯技术效率,技术进步未能成为长江三角洲区域全要素生产率发展的核心竞争力;物流产业集聚、物流资源利用、物流信息化水平对物流效率具有显著的正向作用,产业结构对物流效率的正向作用还未显现出来,能源消耗未通过显著性检验。