Radiative dryness index and potential productivity of vegetation in China

The Chikugo Model is used to estimate radiative dryness indexes (RDI) and net primary productivity (NPP) of vegetation zones in China by calculating cli-matic parameters. That provides the water-heat equilibrium condition, potential primary production for natural vegetation in various vegetation zones, and their geographical distribution pattern. That could be used as the basis for study the effect of global climate change on ecosystems.

Dynamic Prediction Method of Production Logistics Bottleneck Based on Bottleneck Index

In modern manufacturing pattern, there are many uncertain factors in the modern manufacturing process, such as changes of product attribute, changes of manufacturing resources＇ state, and so on, which cause production logistics bottleneck frequently shift, and make decisions of production planning and control based on formed bottleneck deviated from practical production process. Considering these factors, present researches mainly apply afterwards control to optimize production process to passively adapt to bottleneck changes If the direction of bottleneck shifting can be accurately forecasted, the transition from afterwards control of chasing bottleneck to beforehand control can be realized. Therefore, aiming at the phenomenon of production logistics bottleneck shifting under uncertain manufacturing circumstances, this paper starts off with dynamic property of capability and requirement and then builds the concepts of bottleneck degree and bottleneck index to describe dynamic bottleneck characteristic of production unit; taken production capability, production load and quality assurance capability into consideration, mathematical model of bottleneck index is established to measure bottleneck degree accurately, consequently, quantitative research on mechanism of production logistics shifting is achieved. Based on bottleneck index, the prediction model of production logistics bottleneck is founded to predict dynamic change of bottleneck accurately. Finally, an example of forecasting and monitoring the production logistics bottleneck in one manufacturing shop is given to testify the validation and practicability of the prediction method.

Estimation of net primary productivity and its driving factors in the Ili River Valley,China

Net primary productivity（NPP）, as an important variable and ecological indicator in grassland ecosystems, can reflect environmental change and the carbon budget level. The Ili River Valley is a wetland nestled in the hinterland of the Eurasian continent, which responds sensitively to the global climate change. Understanding carbon budget and their responses to climate change in the ecosystem of Ili River Valley has a significant effect on the adaptability of future climate change and sustainable development. In this study, we calculated the NPP and analyzed its spatio-temporal pattern of the Ili River Valley during the period 2000–2014 using the normalized difference vegetation index（NDVI） and an improved Carnegie-Ames-Stanford（CASA） model. Results indicate that validation showed a good performance of CASA over the study region, with an overall coefficient of determination（R2） of 0.65 and root mean square error（RMSE） of 20.86 g C/（m^2·a）. Temporally, annual NPP of the Ili River Valley was 599.19 g C/（m^2·a） and showed a decreasing trend from 2000 to 2014, with an annual decrease rate of –3.51 g C/（m^2·a）. However, the spatial variation was not consistent, in which 55.69% of the areas showed a decreasing tendency, 12.60% of the areas remained relatively stable and 31.71% appeared an increasing tendency. In addition, the decreasing trends in NPP were not continuous throughout the 15-year period, which was likely being caused by a shift in climate conditions. Precipitation was found to be the dominant climatic factor that controlled the inter-annual variability in NPP. Furthermore, the correlations between NPP and climate factors differed along the vertical zonal. In the medium-high altitudes of the Ili River Valley, the NPP was positively correlated to precipitation and negatively correlated to temperature and net radiation. In the low-altitude valley and high-altitude mountain areas, the NPP showed a negative correlation with precipitation and a weakly positive correlation with temperature and net radiation. The results suggested that the vegetation of the Ili River Valley degraded in recent years, and there was a more complex mechanism of local hydrothermal redistribution that controlled the growth of vegetation in this valley ecosystem.

Examining Forest Net Primary Productivity Dynamics and Driving Forces in Northeastern China During 1982–2010

Forest net primary productivity(NPP) is a key parameter for forest monitoring and management. In this study, monthly and annual forest NPP in the northeastern China from 1982 to 2010 were simulated by using Carnegie-Ames-Stanford Approach(CASA) model with normalized difference vegetation index(NDVI) sequences derived from Advanced Very High Resolution Radiometer(AVHRR) Global Inventory Modeling and Mapping Studies(GIMMS) and Terra Moderate Resolution Imaging Spectroradiometer(MODIS) products. To address the problem of data inconsistency between AVHRR and MODIS data, a per-pixel unary linear regression model based on least squares method was developed to derive the monthly NDVI sequences. Results suggest that estimated forest NPP has mean relative error of 18.97% compared to observed NPP from forest inventory. Forest NPP in the northeastern China increased significantly during the twenty-nine years. The results of seasonal dynamic show that more clear increasing trend of forest NPP occurred in spring and autumn. This study also examined the relationship between forest NPP and its driving forces including the climatic and anthropogenic factors. In spring and winter, temperature played the most pivotal role in forest NPP. In autumn, precipitation acted as the most important factor affecting forest NPP, while solar radiation played the most important role in the summer. Evaportranspiration had a close correlation with NPP for coniferous forest, mixed coniferous broadleaved forest, and broadleaved deciduous forest. Spatially, forest NPP in the Da Hinggan Mountains was more sensitive to climatic changes than in the other ecological functional regions. In addition to climatic change, the degradation and improvement of forests had important effects on forest NPP. Results in this study are helpful for understanding the regional carbon sequestration and can enrich the cases for the monitoring of vegetation during long time series.

Balancing timber production and habitat conservation of Okinawa Rails(Gallirallus okinawae): Application of a harvest scheduling optimization model in subtropical forest in Okinawa, Japan

Finding the right balance between timber production and the management of forest-dependent wildlife species,present a difficult challenge for forest resource managers and policy makers in Okinawa,Japan.A possible explanation of this can be found in the unique nature of the forest management area which is populated with various kinds of rare and endangered species.This issue has been brought to light as a result of the nomination of northern Okinawa Island in 2018 as a candidate for World Natural Heritage site.The nomination has raised public awareness to the possibility of conflicting management objectives between timber extraction and the conservation of habitat for forest-dependent wildlife species.Managing exclusively for one objective over the other may fail to meet the demand for both forest products and wildlife habitat,ultimately jeopardizing the stability of human and wildlife communities.It is therefore important to achieve a better balance between the objective of timber production and conservation of wildlife habitat.Despite the significance of this subject area,current ongoing discussions on how to effectively manage for forest resources,often lack scientific basis to make sound judgement or evaluate tradeoffs between conflicting objectives.Quantifying the effect of these forest management activities on wildlife habitat provides useful and important information needed to make forest management and policy decisions.In this study we develop a spatial timber harvest scheduling model that incorporates habitat suitability index(HSI)models for the Okinawa Rail(Gallirallus okinawae),an endangered avian species found on Okinawa,Japan.To illustrate how the proposed coupling model assembles spatial information,which ultimately aids the study of forest management effects on wildlife habitat,we apply these models to a forest area in Okinawa and conduct a simple simulation analysis.

The growth and production modeling of individual trees of Eucalyptus urophylla plantations

Individual tree models(ITMs)are classified as growth and production models for projecting current and future forest stands.ITMs are more complex than other growth and production models,show a higher level of detail and,consequently,produce a better modeling resolution.However,the accuracy and efficiency of ITMs have not been properly assessed to date.In this study,we estimated the growth in height,diameter,and individual tree volume of a Eucalyptus urophylla plantation by applying an ITM.We used a continuing forest inventory dataset in which 1554 individual trees within 29 permanent plots were measured in the field over a 6-year period(24 to 72 months).Each individual tree volume was estimated for future tree age.To achieve this,we adjusted the model to predict the height and diameter growth,and the probability of mortality as a function of the competition index.The ITM accuracy was assessed based on the analysis of variance results and,subsequently,the multiple mean comparison test at the 5%significance level.The tree volumes predicted by the ITM for the forest stand aged 72 months,beginning at ages 24,36,48,and 60 months,were compared to the field measured tree volume acquired from the 72-month forest inventory that was used as the reference age.Estimated and observed tree volumes were similar when the estimation was based on the 48-month forest plots.These results might help to reduce financial costs of forest inventory because the ITM produces accurate future predictions of forest stand stocks.Our estimated ITM for Eucalyptus plantations using measurement intervals up to 2 years is recommended because it significantly reduced the projected volume discrepancy compared to the field measurements.

黑龙江省数字经济产出效率差异研究

基于2012—2020年黑龙江省13个城市的面板数据,利用BCC-DEA模型和Malmqui ST指数模型分别测算黑龙江省数字经济产出水平和全要素生产率。研究发现:黑龙江省各城市的数字经济产出效率存在明显差异。从静态效率分析,黑龙江省东部技术效率最高,北部次之,南部最低,这主要是因为东部和北部规模效率要高于南部。从动态效率分析,黑龙江省各市的全要素生产率波动上升,与技术进步指数发展趋势基本一致。

中国碳排放全要素生产率的区域演进及其影响机制——基于胡焕庸线的实证分析

提升碳排放全要素生产率是全面建设中国式现代化的内在要求。运用NCSE-EBM与Malmquist Luenberger指数相结合的模型测度和分析2011—2020年我国30个省份碳排放全要素生产率及其区域动态演进特征,并采用灰色关联方法探讨区域碳排放全要素生产率演变的影响机制。结果显示:碳排放全要素生产率在空间上表现为胡焕庸线西北和东南区域高、沿线区域低的“V”型分布态势;三大区域碳排放全要素生产率均不存在严格收敛;效率改善指数是碳排放全要素生产率提升的内在主导性因素;产业结构是我国三大区域碳排放全要素生产率的最主要影响因素,技术创新与胡焕庸线西北区域和东南区域碳排放全要素生产率的关联度最低,而数字化与胡焕庸线沿线区域碳排放全要素生产率关联度最小。

农业PPP对农业绿色全要素生产率的影响研究——基于长江经济带的实证分析

提升农业绿色全要素生产率是农业高质量发展的关键体现,而政府与社会资本合作模式(PPP模式)是一种有效的农业投融资模式。运用非径向SBM模型方向性距离函数的ML指数法分别测算了2016-2020年长江经济带农业绿色全要素生产率水平及分解项(技术效率和技术进步),结合面板固定回归模型实证研究了农业农村领域的PPP模式对长江经济带农业绿色全要素生产率的影响及内在机制。结果表明:农业PPP在5%的水平上显著提高长江经济带农业绿色全要素生产率,且上下游地区的影响存在区域异质性,下游地区效应更大,通过稳健性检验后该结论仍然成立。此外,产业结构、城镇化、技术水平、土地规模化与农业绿色全要素生产率呈现显著正相关。最后提出了相应建议,以期提高长江经济带农业绿色全要素生产率,进而实现农业高质量发展的战略目标。

基于DPSIR模型的牧草产品质量安全评价指标体系构建及应用

构建一个具有通用性的牧草产品质量安全指标体系,用以评估各区域的牧草产品质量安全水平,是完善国家生态草牧业体系建设的重要基础性工作。本研究在驱动力-压力-状态-影响-反应(DPSIR)模型概念框架下,基于已发布的饲草标准和文献统计资料,系统梳理影响牧草产品质量安全的相关指标,筛选出14个指标,即牛羊肉人均消费量、畜牧机械数量、保鲜存储设备数量、年日照时长、年降水总量、粗蛋白含量、中性洗涤纤维含量、酸性洗涤纤维含量、干物质消化率、牛肉年产量增长率、羊肉年产量增长率、牛羊出栏总量、地区条例标准出台个数、质量监管力度。采用层次分析法(AHP)量化各指标权重,发现粗蛋白含量的权重最高,中性和酸性洗涤纤维含量次之,保鲜存储设备数量权重最小。基于本研究构建的牧草产品质量安全评价指标体系,对青海省同德县和甘肃省山丹县的天然牧草产品进行质量安全评价,结果表明同德县的天然牧草产品质量安全高于山丹县,对应安全等级分别为二级、三级。牧草产品质量安全评价指标体系的构建,为提高牧草产品品质、保障奶畜养殖的安全及为草牧业发展提供科学指导。

基于BEPS模型的塞罕坝植被净初级生产力时空变化分析研究

叶面积指数(leaf area index,LAI)是北部生态系统生产力模拟模型(boreal ecosystem productivity simulator,BEPS)的关键驱动数据,获取高精度LAI对区域森林生态系统碳循环十分重要,然而当前大多研究采用的MODIS LAI产品缺乏可信度。为此,基于LAI动态模型、PROSAIL辐射传输模型和层状贝叶斯网络(Hierarchical Bayesian Network,HBN)构建数据同化系统,获得空间分辨率为20 m的LAI数据,驱动BEPS模型,模拟塞罕坝机械林场2011—2021年的植被净初级生产力(Net Primary Productivity,NPP),并对NPP时空变化特征及影响因子进行分析。结果表明,基于贝叶斯同化方法获得的高分辨率LAI数据极大提高了MODIS LAI产品的精度;基于同化后的LAI数据驱动BEPS模型获取模拟森林NPP,与样地实测数据计算NPP间相关性较高(R^(2)=0.77);2011—2021年塞罕坝机械林场植被NPP平均值为307.4 g/(m^(2)·a),森林NPP呈现平稳增长趋势;不同植被类型模拟NPP存在较大差异,针叶林、落叶林及混交林模拟NPP分别为484.9、402.4、287.9 g/(m^(2)·a);植被NPP与温度因子相关性较高,偏相关系数为0.2~0.8,而植被NPP与降水量的相关性总体而言相对较低,其偏相关系数为-0.3~0.4,在该地区降水量对植被NPP的影响较低,温度为该地区NPP变化的主导因子。研究结果可获取高空间分辨率的LAI数据,为森林生态系统碳循环的精准时空模拟提供依据。

新疆生产建设兵团农产品物流效率及差异动态研究

新疆生产建设兵团农产品丰富,利用物流可以带动农产品的销售,增加农户收入,从而更好地促进新疆生产建设兵团农业的发展。首先从兵团农产品生产与消费现状、兵团农产品物流发展现状这两个方面对兵团农产品物流的现状进行分析,其次运用超效率DEA模型以及DEA-Malmquist指数法,选取2015—2020年兵团的面板数据,对兵团农产品物流效率进行静态和动态分析,从而厘清兵团农产品物流的时空演变规律。结果表明,兵团农产品物流效率整体水平较低,各师农产品物流发展水平差异较为显著,发展水平参差不齐。最后,从重视农产品物流人才引进、完善兵团农产品物流基础设施以及注重新型农产品物流技术引用等方面提出了提升兵团农产品物流效率发展水平,进而更好地促进兵团农产品物流发展的建议。

中国蔬菜绿色全要素生产率时空特征与空间错位

为评估中国蔬菜绿色生产率,提升蔬菜生产绿色发展水平,推进农业高质量发展。该研究采用超效率SBMML模型、空间错位指数、主成分分析法等方法,探究2011—2020年中国30个省市蔬菜绿色全要素生产率的时空格局演变与空间错位特征,识别影响中国蔬菜绿色全要素生产率的主要因素。研究结果发现:1)2011—2020年中国蔬菜绿色全要素生产率整体呈下降趋势,由1.023 1降低到0.741 4,蔬菜生产与生态环境可持续发展的协调程度降低,其中技术效率下降和技术退步共同拖累了蔬菜绿色全要素生产率的提高。2)2011—2020年中国蔬菜绿色全要素生产率增长呈“东高西低,南高北低”的空间分布特征。北回归线以南产区蔬菜绿色全要素生产率最高,西北产区蔬菜绿色全要素生产率最低,其差异主要取决于水土资源供给状况与市场需求规模等因素。3)2011—2020年中国蔬菜绿色全要素生产率与技术效率的空间错位由北向南大致呈现“正向错位—负向错位”的变化趋势,整体以低错位为主。东北产区、中部产区地势平坦,农业生产条件良好,有利于蔬菜规模化种植。2011—2020年中国蔬菜绿色全要素生产率与技术进步的空间错位呈显著的“东正西负”的空间分布特征,且空间错位程度较大,负向错位省份数量由13个增至17个。由于蔬菜生产过于追求经济效益,忽视了绿色生产技术的投入。4)经济发展水平、资源环境禀赋和交通通达性是影响中国省域蔬菜绿色全要素生产率变化的主要因素,其中城镇化率和人均可支配收入等经济要素对蔬菜绿色全要素生产率的影响最为明显。研究结果可准确把握现阶段蔬菜绿色生产现状,为农业绿色转型发展提供借鉴。

基于综合视角的县域国土空间冲突测度与功能优化——以江西省宜黄县为例

[目的]测度国土空间冲突强度,分区探讨国土空间冲突管理和优化国土空间利用途径,为县域国土空间可持续开发利用提供新的思路。[方法]以江西省宜黄县为例,通过景观生态指数模型、可开发强度分析、用地现状与适宜性评价叠加3种方法,以“把握景观格局—明确开发强度—摸底适宜性—实现功能优化”综合视角为导向,构建综合视角下国土空间冲突测度模型,识别乡镇尺度下空间显著冲突与区域本位基底相耦合的综合冲突类型区,进而提出功能优化措施。[结果]①2010—2020年宜黄县城镇化趋势扩大,生态空间的容纳度变低,国土空间主要表现为农业生产空间和生态空间向工矿生产空间和城镇生活空间转移。②2010—2020年宜黄县区域空间冲突强度加剧,不同时段和区域下空间冲突强度和分布情况差异显著,可控空间主要分布在南部,轻度和中度冲突在域内分布较为均匀,重度冲突主要分布在北部、中部和东部。③根据开发强度和冲突产生诱因,可将宜黄县乡镇划分为地形发展劣势区、城镇开发密集区和自然保护地集中区3类,作为空间功能优化的重点。④宜黄县乡镇尺度上空间冲突类型区分布存在差异性,表现为:农业空间与生态空间冲突>城镇空间与生态空间冲突>城镇空间冲突>农业空间冲突。⑤由综合冲突测度模型,得到宜黄县域内包含8种综合冲突组合,归并后可分为城镇扩张无序、城镇规模扩张、城镇规划不当、总体发展滞后和城镇发展滞后5种冲突类型。[结论]2010—2020年宜黄县空间冲突强度加剧,区域生态安全和粮食安全受到不断挑战。应当加强空间冲突分区管控,针对性优化区域国土空间资源开发利用。

基于Super-SBM方法的省级交通运输行业碳排放效率评估研究

随着全球气候变化日益加剧,交通运输行业的碳排放效率评估与提升备受关注。本文利用Super-SBM模型,结合非期望产出,对2012-2019年我国30个省级行政区的交通运输行业碳排放效率进行了全面评估。在此基础上,运用Malmquist生产率指数(MPI)及其分解方法,揭示了不同区域间交通运输业碳排放效率的变化趋势。研究结果为加强省级交通运输业的环保措施、促进碳减排提供了科学依据,为政策制定者提供了重要参考。

新型城镇化·新型工业化与农业绿色全要素生产率——基于长江经济带面板数据的分析

基于2002—2021年长江经济带11省市的面板数据,分别利用SBM-GML指数法和熵值法测算了长江经济带的农业绿色全要素生产率水平和新型城镇化、新型工业化水平,然后运用面板Tobit模型分析了新型城镇化、新型工业化对农业绿色全要素生产率的影响。结果表明:2002—2006年间长江经济带各省市的农业绿色全要素生产率水平还不尽人意,但2007—2021年该经济带各省市的农业绿色全要素生产率水平均显著提升,同时长江经济带的新型城镇化、新型工业化水平也呈稳步上升趋势;新型城镇化、新型工业化对长江经济带农业绿色全要素生产率水平的提升具有显著的正向影响,且新型工业化的影响更大。基于此,为了进一步挖掘长江经济带新型城镇化、新型工业化对农业绿色全要素生产率提升的潜力,建议长江经济带各省市在稳步推动新型城镇化发展的同时不断为新型工业化注入新的“活力”,为提升当地的农业绿色全要素生产率水平助力,同时还要通过优化农业产业结构、改造农村电网等方式进一步减少非合意产出。

和田地区耕地时空演变的生产-生态效应研究

耕地在干旱区土地利用中是贡献显著的重要地类,分析其生产-生态效应时空变化有助于解释耕地变化在区域粮食生产与生态环境保护中的作用,为实现生产-生态协同保护提供参考。本研究基于1990、2000、2010、2020年的土地利用分类数据,运用土地利用转移矩阵、耕地生产水平假设模型、遥感生态指数(RSEI)模型,揭示和田地区耕地时空演变下的生产-生态效应。结果表明:1990—2020年,研究区耕地面积增加了1702.63 km^(2)。8个县(市)耕地面积变化趋势相同,但差异显著,未利用地开垦和林、草地复垦是新增耕地的主要来源;退耕还林还草、建设用地扩张和耕地荒废是耕地减少的主要原因;耕地生产水平向好发展,无生产耕地占比下降12个百分点,中、中高生产耕地总占比增加14个百分点。从耕地生产效应来看,研究区固定耕地生产正效应(面积占比55%)大于负效应(面积占比2%),耕地转移效应(面积占比43%)有效弥补了流失的生产效应面积,然而从各阶段效应来看,固定负效应面积逐渐增加,固定正效应面积逐渐减少,转移效应面积呈现波动下降趋势。研究区耕地等级主要为一般生态等级,耕地生态环境质量呈恶化趋势,固定耕地生态环境质量恶化面积为改善面积的2倍以上;转移耕地恶化面积为改善面积的近1.4倍。阶段性变化中,耕地生态环境质量在前20年得到改善,而后10年出现恶化,其原因在于固定耕地和转出耕地生态环境质量下降。研究表明,研究区耕地变化促进了区域生产的提高,但同时导致耕地生态环境质量逐渐恶化。因此,在未来的国土空间规划与管理中应坚持生产-生态融合发展,优化土地资源配置。

纵向产业结构、价格指数背离与南北经济差距扩大

区域协调发展是加快构建新发展格局,推动高质量发展的重要保障。近年来,南北经济差距呈现分化态势,无疑会对我国经济社会带来不利影响。文章梳理了纵向产业结构、价格指数背离、南北经济差距扩大之间的传导链条及作用机制。实证发现,价格指数背离在纵向产业结构对地区经济发展的影响中起到中介作用:纵向产业结构中,上游产业占比越大,价格指数背离幅度越大,而价格指数背离又会抑制地区经济增长。模型机制分析表明,在纵向产业结构下,由于上下游产品生产中本地要素所占比例的差异,进口要素价格冲击对下游本地要素具有更强的“挤入效应”,推高下游总成本进而遏制CPI下降,致使CPI降幅小于PPI,形成价格指数背离,进而抑制偏重上游产业的北方地区产出增长。“反事实”模拟表明,纵向产业结构增强进口要素价格对下游本地要素的“挤入效应”,加剧价格指数背离。由此可见,纵向产业结构增大地区价格指数背离幅度,加深对偏重上游产业的北方地区经济抑制,最终加剧南北经济分化。

乡村振兴背景下欠发达地区农业生产效率评价研究——以重庆市为例

欠发达地区农业生产效率的提高为实现乡村振兴有重要意义。本文利用DEA-BCC模型和DEA-Malmquist指数对重庆市及其37个区县的农业生产效率进行评价研究并进一步分析其影响因素。研究表明,在全市层面,2016—2020年重庆市农业生产效率呈上升趋势,但大多数年份处于DEA无效状态,主要原因是规模效率低;全要素生产率稳步提升,平均每年增长10.7%;在区县层面,2016—2020年重庆市农业生产效率较高,但存在明显的区域差异,DEA有效区县主要集中于大都市区,全要素生产率大小依次为渝东南城镇群>渝东北城镇群>大都市区。影响因素中,单位耕地机械投入、单位耕地化肥投入、有效灌溉耕地占比、政府投入是促进因素,产业结构、粮食播种面积占比为限制因素。据此,提出实施农业生产要素现代化战略和农业区域分工差异化策略。

长三角两业融合对服务业全要素生产率的影响

随着数字技术的发展,先进制造业与现代服务业之间的边界逐渐模糊,两业融合发展成为提升服务业生产率进而促进经济增长的重要方式。利用耦合协调模型和DEA(数据包络分析)-Malmquist指数法分别对长三角地区两业融合水平和服务业全要素生产率进行测度,实证两业融合对服务业全要素生产率的正向作用,且主要通过两业融合对技术进步的促进作用来实现。