黄河三角洲典型区土壤盐分空间分布预测方法研究

[目的]正确评估土壤盐渍化状况,掌握土壤盐分空间分布规律,是合理开发利用盐渍化土壤资源的基础和前提。[方法]文章选取黄河三角洲典型地区垦利县作为采样区,利用4种确定性方法 (全局多项式、局部多项式、反距离加权、径向基函数)和3种地统计不确定性方法 (普通克里格、简单克里格、协同克里格),分别对研究区进行土壤含盐量的空间分布特性估计,从误差和空间分布特点上对比分析不同方法的预测效果,并明确了研究区土壤盐分的空间分布特征。[结果]地统计不确定性插值方法的精度整体上优于确定性方法,简单克里格预测后的空间表达和误差精度均属最优。基于最优的空间预测方法,黄河三角洲土壤盐分目前在空间上整体呈现出东部高于西部的趋势,且部分区域存在斑块状现象。非盐渍化、轻度盐渍化、中度盐渍化、重度盐渍化和盐土面积分别占研究区总面积的2.54%、27.14%、43.70%、21.21%和5.41%。[结论]在土壤属性变异强度大的时候,采用简单克里格效果会更好。     

A spatial high-resolution model of the dynamics of agricultural land use

An area model is presented for agricultural land use, based on a generalized linear mixed model. This model is spatially explicit and dynamic and, although it uses aggregated data, allows for heterogeneity of behavior among individual farmers. The parameters of the fixed component of the model are obtained using an estimation equations approach, and the structure of spatiotemporal correlation is assessed using empirical semivariograms. The model is illustrated using as an example the dynamics of agricultural land use in the Lower Guadalquivir area in Spain. A simulation study indicates that the model gives poor results if the heterogeneity of individual behavior and spatiotemporal autocorrelation are ignored.     

Past and future impacts of land use and climate change on agricultural ecosystem services in the Czech Republic

Climatic and land use change are amongst the greatest global environmental pressures resulting from anthropogenic activities. Both significantly influence the provision of crucial ecosystem services, such as carbon sequestration, water flow regulation, and food and fibre production, at a variety of scales. The aim of this study is to provide spatially explicit information at a national level on climate and land use change impacts in order to assess changes in the provision of ecosystem services. This work provides a qualitative and quantitative analysis of the impacts on selected ecosystem services (carbon sequestration, food production and soil erosion) in the agricultural sector of the Czech Republic. This assessment shows that, historical land use trends and land use under projected climate scenarios display some shared spatial patterns. Specifically, these factors both lead to a significant decrease of arable land in the border fringes of the Czech Republic, which is to some extent replaced by grasslands, in turn affecting the provision of ecosystem services. Moreover, this assessment contributes to a useful method for integrating spatially explicit land use and climate change analysis that can be applied to other sectors or transition countries elsewhere.     

基于OLI影像的乌裕尔河—双阳河流域土壤碱化反演研究

近年来受环境变化和人类活动的影响,土壤盐碱化是土地退化的表现之一。研究土壤盐碱化有利于改善现状,并且预防其加剧具有重要意义。土壤碱化的快速反演和及时监测,对乌—双河流域生态可持续发展有着重大意义。以Landsat-8OLI遥感影像与野外采样测定的170个样点土壤p H值和EC为数据基础,实验室内采集光谱,建立光谱反射率及其变换形式与土壤p H值和EC的相关分析,选择最佳敏感波段,利用线性回归分析建立基于OLI影像的乌裕尔河—双阳河流域土壤盐碱化反演模型,该模型的建立可为区域土壤碱化信息的提取及监测提供参考。     

Chinese land policies and farmers’ adoption of organic fertilizer for saline soils

Soil salinization has become a global concern and poses a great threat to food production and sustainable land use. Land use policies are the main driver of saline soil farmland use in ecosystems. This paper proposes a theoretical framework for analyzing how saline soil farmland use is affected by land use practices of individual farm households. An empirical study, using an ordered probit model, was conducted based on questionnaire responses from farm households in 8 towns and 14 villages in eco-fragile areas in Shandong, Jilin and Xinjiang provinces. The results suggest that land tenure, state systems agricultural support, characteristics of a field parcel and characteristics of the farm households have different influences on farmer's land use in three regions. The adoption of organic fertilizer by individual households is constrained by the lack of stability and integrity in land tenure. Furthermore, the parcel of a field is generally small, sparsely distributed and often fragmented, which increases costs. Even subsidizing organic fertilizer does not necessarily help in its adoption. Given these challenges, this study makes recommendations for different regions that may promote the adoption of improved saline soil farmland cultivation methods by farmers.     

干旱区盐渍化农田景观格局特征分析

干旱区农田土壤盐渍化问题突出且日趋严重,已成为制约绿洲农业发展的主要障碍之一。以玛纳斯县为研究区,运用景观生态学方法和GIS技术,选取相关景观格局指数,对农田盐渍化景观格局及土壤盐渍化程度与景观格局关系进行定量分析。结果表明:(1)研究区以轻度盐渍化农田为主,农田土壤盐分在水平方向的变异程度随着深度的增加而降低,总体来看,农田斑块形状较规则、简单且面积变化幅度较大。(2)类型水平土壤盐渍化程度对农田斑块面积影响显著,随着土壤盐渍化程度增加而农田斑块面积减小。盐渍化程度对类型斑块间距离影响明显,轻度盐渍化程度农田斑块呈集中分布,而其它类型类型斑块间距离较大,相对分散分布。(3)斑块水平土壤深度(0~100cm)范围内,土壤含盐量与农田斑块形状、面积和邻近斑块数关系密切。盐渍化农田盐渍化程度愈重,其农田斑块形状愈复杂,农田斑块面积愈小,农田斑块邻近斑块数愈少。中层盐渍化程度对农田斑块形状和面积影响相对较大,底层盐渍化程度对农田斑块集中连片分布特征影响较大。     

Spatially explicit micro-level modelling of land use change at the rural–urban interface

This paper describes micro‐economic models of land use change applicable to the rural‐urban interface in the US. Use of a spatially explicit micro‐level modelling approach permits the analysis of regional patterns of land use as the aggregate outcomes of many, disparate individual land use decisions distributed across space. In contrast to the models featured by Nelson and Geoghegan, we focus on models that require spatially articulated data on parcel‐level land use changes through time. In characterising the spatially disaggregated models, we highlight issues uniquely related to the management and generation of spatial data and the estimation of micro‐level spatial models.     

Global food demand,productivity growth,and the scarcity of land and water resources: a spatially explicit mathematical programming approach

In the coming decades, an increasing competition for global land and water resources can be expected, due to rising demand for food and bio‐energy production, biodiversity conservation, and changing production conditions due to climate change. The potential of technological change in agriculture to adapt to these trends is subject to considerable uncertainty. In order to simulate these combined effects in a spatially explicit way, we present a model of agricultural production and its impact on the environment (MAgPIE). MAgPIE is a mathematical programming model covering the most important agricultural crop and livestock production types in 10 economic regions worldwide at a spatial resolution of three by three degrees, i.e., approximately 300 by 300 km at the equator. It takes regional economic conditions as well as spatially explicit data on potential crop yields and land and water constraints into account and derives specific land‐use patterns for each grid cell. Shadow prices for binding constraints can be used to valuate resources for which in many places no markets exist, especially irrigation water. In this article, we describe the model structure and validation. We apply the model to possible future scenarios up to 2055 and derive required rates of technological change (i.e., yield increase) in agricultural production in order to meet future food demand.     

An interdisciplinary approach to regional land use analysis using GIS, with applications to the Atlantic Zone of Costa Rica

Policy makers and other stakeholders concerned with regional rural development increasingly face the need for instruments that can improve transparency in the policy debate and that enhance understanding of opportunities for and limitations to development. To this end, a methodology called SOLUS (Sustainable Options for Land Use) was developed by an interdisciplinary team of scientists over a 10-year period in the Atlantic Zone of Costa Rica. The main tools of SOLUS include a linear programming (LP) model, two expert systems that define technical coefficients for a large number of production activities, and a geographic information system (GIS). A five-step procedure was developed for GIS to spatially reference biophysical and economic parameters, to create input for the expert systems and the LP model, to store and spatially reference model output data, and to create maps of both model input and output data. SOLUS can be used to evaluate the potential effects of alternative policies and incentive structures on the performance of the agricultural sector. A number of practical applications demonstrate SOLUS's capability to quantify trade-offs between economic objectives (income, employment) and environmental sustainability (soil nutrient balances, pesticide use, greenhouse gas emissions). GIS-created maps visualize the spatial aspects of such trade-offs and indicate hotspots where local goals may conflict with regional goals.     

安徽省农业功能区划研究初探

该文选取农业功能分区4组代表性的指标,采用K-均值聚类分析对安徽省进行农业功能分区。同时,兼顾多方面因素考虑,对分区方案中个别县区进行调整,形成了安徽省农业功能区划初步方案,并分析了各功能区的主导功能和拓展功能。     

Spatial Effects within the Agricultural Land Market in Northern Ireland

The importance of dealing properly with spatial effects, such as spatial autocorrelation, in cross‐sectional econometric estimation has become more widely recognised in recent years. Spatial autocorrelation is similar in many ways to serial correlation, but while the latter is ordered on a one‐dimensional time axis, the former is ordered in two dimensions. The multi‐directional nature of spatial dependence means that specialised techniques are needed for diagnostic testing and estimation purposes. This paper uses these specialised diagnostics to test for spatial effects within a hedonic pricing study of the agricultural land market. The tests indicate that spatial autocorrelation (in the form of spatial lag dependence) and spatially distinct sub‐markets (or spatial heterogeneity) are present. Ignoring these effects in the estimation process is likely to lead to biased parameter estimates. Consequently, we re‐specify the hedonic model to allow for these spatial effects. The presence of spatial lag dependence suggests that there is circularity of price setting within the agricultural land market. This means that agricultural land prices are not solely determined by the inherent characteristics of the land, but tend to reflect also the average local price per acre.     

A conceptual framework and its software implementation to generate spatial decision support systems for land use planning

In a context where several sectors of society compete for space, land use types must be carefully designed and spatially allocated to guarantee a sufficient level of relevant ecosystem services (ES) in a territory of interest. In this respect, contemporary land use planning involves multiple, often conflicting objectives and criteria. Consequently, major benefits can be expected from spatial decision support systems (sDSS) designed to deal with complex spatial allocation problems.This paper presents the generic conceptual framework ‘OSMOSE’ and its free and open source software implementation, for the generation of specific sDSSs for spatial land use planning. The specific sDSSs generated with OSMOSE are meant to (i) identify land units which meet multiple predefined ES-attribute values for a specific land use type (LUT) and (ii) rank land units for a given LUT according to these multiple ES-attributes. A complementary purpose is to (i) identify and (ii) rank LUTs for a given land unit. Whereas ‘identification’ is done by means of a threshold query, ‘ranking’ is based on the Iterative Ideal Point Thresholding (IIPT) method. The proposed framework is extremely flexible as it can accommodate differentially weighted, continuous and/or ordinal attributes with, for the latter, equal or unequal number of classes, alternative land unit definitions and land use types. Moreover, assessments cannot only be made using ES-levels for the land unit/LUT combinations but also in terms of changes in ES-levels after a particular change of LUT.The OSMOSE framework is illustrated by means of the specific sDSS BoLa which is generated to support land use planning in the region of Flanders (Belgium) with focus on soil protection. Four cases are presented in which the decision support varies between the available approaches (threshold – selection, threshold – ranking, IIPT – selection, IIPT – ranking).     

广西边境地区耕地非农化的空间特征与迁移路径

目的 耕地非农化影响1.2亿hm²（18亿亩）耕地保护红线现象引起了政府和学界的高度重视，有效掌握耕地非农化演变空间特征是保护耕地的重要前提。方法 文章以广西边境3个地级市的23个县域地区为研究区，通过构建重心模型、标准差椭圆模型分析刻画1980—2018年耕地非农化速度与方向，并利用空间自相关分析其空间特征。结果 （1）1980—2018年4个时期内耕地非农化面积呈“N”型波动增长的趋势，其中2010—2018年耕地非农化面积最大，为49 367 hm²；1990—2000年耕地非农化面积最小，为5 270 hm²，耕地非农化面积高值区主要集中在城镇化水平较高的区域城市中心。（2）耕地非农化速度具有空间非均衡性，标准差椭圆面积往东南方向持续扩张，耕地非农化空间上总体由西北部往东南方向迁移，区域之间的差距逐渐扩大。（3）广西边境地区耕地非农化面积存在显著的空间正相关关系，但集聚优势逐渐下降，“高—高”聚类的空间变化主导了耕地非农化面积的空间自相关关系的格局演变。结论 研究揭示了广西边境地区耕地非农化空间格局演变过程，可为边境地区制定耕地非农化管控机制和优化国土空间结构提供参考。     

高台县耕地地力评价

[目的]根据高台县耕地地力评价结果和不同地力等级统计结果,分析耕地质量存在的问题,并为高台县耕地地力保护和耕地质量提升提出建议对策。[方法]把甘肃省张掖市高台县土壤图、土地利用现状和行政区划图叠加求交,得到3.309 3万个评价单元。利用特尔斐法选取耕层盐化、质地构型、有机质、质地、有效磷、耕层厚度、海拔、CEC(土壤阳离子交换量,下同)、速效钾和坡度作为高台县耕地地力评价指标体系并建立层次分析模型和隶属函数模型,由专家打分取平均值给出各层次权重和评价指标的隶属度。再使用GIS软件根据公式计算耕地地力综合指数IFI值。[结果]IFI值0.850 5的划为一等地,IFI值在0.850 5~0.720 0的划为二等地,IFI值在0.720 0~0.662 6的划为三等地,IFI值在0.662 6~0.630 0的划为四等地,IFI值0.630 0的划为五等地。[结论]当前耕地存在的主要问题是因化肥过量使用造成的面源污染和灌溉造成的盐渍化,建议从改良耕作制度、轮作休耕、化肥减量增效、增施有机肥、节水灌溉技术和秸秆还田等措施加以改良。     

一种新的粮食安全评价方法研究

该文提出了一个综合自然、社会和经济等多因子的粮食安全评价方法,选择了人均粮食占有量和人均GDP两个指标来描述粮食安全状况。人均粮食占有量的变化可以表述粮食供给性和稳定性变化状况,人均GDP变化则可以反映粮食可获取性和购买能力的变化,两者综合决定一个国家或地区的粮食安全状况。这两个指标分别和3个空间模型(空间EPIC模型、作物选择模型和IFPSIM模型)关联。利用该方法,以网格大小为6分弧度的地理单元为评价对象,以2000年为初始年份,对未来2020年的全球粮食安全状况进行了评价。研究表明,粮食供给短缺与贫困是危及粮食安全的最主要因素。到2020年,多数南亚国家和非洲国家,由于其人均粮食占有量和人均GDP两个指标值都显著降低,粮食供应不足和贫困一起将可能导致该区域存在粮食危机和饥饿风险。对于其它区域,日益增长的粮食需求可以通过本区域的粮食生产自给予以满足,或通过外部购买或粮食进口得到满足,总体上不存在粮食安全问题。     

村级尺度耕地产能空间分异及其影响因子分析

[目的]通过探究耕地产能空间分异规律与影响因子,识别地区粮食生产关键制约因素,提升高标准基本农田建设的针对性和建设效果。[方法]采用空间自相关模型刻画了村级尺度耕地产能空间分异规律,对比分析了线性回归模型和地理加权回归模型在耕地产能影响因子识别的效果,并依此划分产能提升类型区。[结果](1)海伦市耕地产能呈现中西部高北部偏低的态势,且具有较强的空间自相关特征。(2)海伦市耕地产能与黑土层厚度、出现障碍层深度、耕作距离、田块状况和质地等变量显著相关,且均呈正相关,但在空间上表现出不同程度的异质性。(3)基于地理加权回归模型的耕地产能影响因子,提出了产能保持区、耕作条件改良区、质地改良区、障碍层改良区和保护性耕作区5类耕地产能提升类型区。[结论]文章所采用的基于村级尺度耕地产能及其空间分异因素模型相关研究,能够较好揭示村级耕地产能空间分布特点、空间自相关性特征及影响因子分布特征,基于此所划分的耕地产能提升类型区较已有研究对耕地分类管理具有更精准的支撑作用。     

Cross compliance and the protection of grassland - Illustrative analyses of land use transitions between permanent grassland and arable land in German regions

Permanent grassland combines various ecological functions in terms of nature, soil, water and climate protection. Conversion of grassland to arable land is accompanied by a diminution of these functions. Various developments have led to increased pressure on the EU grassland area. With cross compliance, the EU sets minimum standards for the protection of the ratio of permanent grassland. However, this requirement alone does not ensure the preservation of grassland on sensitive sites, such as water or nature conservation areas or land on organic soils or on steep hills.This paper deals with land use changes between grassland and arable land. For this purpose we analyse data of the EU's Integrated Administration and Control System (IACS) from four German federal states. The described methodology allows to identify gross changes of land use and to distinguish between conversion of permanent grassland and “loss” due to “deactivation” at a highly disaggregated level. Merging IACS-data with further spatially explicit data provides a picture of land use transitions in ecologically sensitive areas and enables conclusions to be drawn about the effectiveness of protection measures.     

Anthropogenic nutrients and eutrophication in multiple land use watersheds: Best management practices and policies for the protection of water resources

Blooms of cyanobacteria (Microcystis aeruginosa) are becoming increasingly recurrent in the A Baxe dam reservoir (Galícia, Northern Spain) as a result of increasing levels of different anthropogenic pressues in the Umia catchment. The aim of this study is to develop a model that allows us to detect the spatial level where the main problems that trigger eutrophication occur. We used Mike Basin coupled with Load Calculator to model and visualize spatially explicit results of stream flow and N and P export. The results indicate increase in nitrogen (N) and phosphorus (P) concentrations that trigger eutrophication.High concentrations of nutrients at the Upper Umia derive from livestock, while at the Lower Umia the origin is sewage, highlighting impacts from diffuse pollution and point source pollution in different areas of the basin. Cyanobacteria blooms result from the influence of both contaminant sources, being also triggered by local environmental conditions such as temperature, solar radiation or flow rate. This model will be useful for predicting possible changes, alterations and evolutions that occur in the watershed, that can help ensure compliance with the Water Framework Directive. In addition to the model developed, the results indicate the need for the implementation of management practices in order to reduce the blooms of cyanobacteria (green systems for wastewater in rural areas, riparian forest restoration, etc.). Some sub-basins, such as the Gallo sub-basin, require immediate action since they are major contributors of nutrients to the main river as a result of the low carrying capacity of local waste water treatment plants.     

粤港澳大湾区城市群国土开发强度及其生态效益相关性评价

快速城市化导致了大面积的城市扩张和大规模的生态破坏,随着城镇化发展到以城市群为主体的阶段,探讨城市群国土开发活动与生态环境之间的关系对于指导区域开发战略具有重要意义。本文以粤港澳大湾区城市群为研究区,从投入、产出以及土地联系三个角度构建国土开发强度模型,通过测算生态系统服务价值反映国土开发活动的生态效益,运用双变量空间自相关模型、普通最小二乘法以及空间回归模型对二者之间的相关关系进行测度。结果表明,(1)在研究期内,粤港澳大湾区城市群国土开发强度呈现显著提升,土地开发活动的生态效益有略微下滑;(2)国土开发强度与生态系统服务价值之间呈现负相关关系,并且具有空间依赖性。国土开发活动与生态系统之间是一个相互影响的复杂系统,未来要加强城市群生态系统的统筹管理。     

Land use and land cover scenarios: An interdisciplinary approach integrating local conditions and the global shared socioeconomic pathways

Land Use and Land Cover (LULC) changes have profound impacts on the functioning of (agro)ecosystems and have potential to mitigate global climate change. However, we still lack interdisciplinary methods to project future LULC scenarios at spatial scales that are relevant for local decision making and future environmental assessments. Here we apply an interdisciplinary approach to develop spatially explicit projections of LULC at a resolution of 30 × 30 m informed by historic relationships between LULC and their key drivers, within the context of the four qualitative scenarios of global shared socioeconomic pathways. We apply this methodology to a case study in the Zona da Mata, Brazil, which has a history of major LULC changes. The analysis of LULC changes from 1986 to 2015 indicates that pasture area decreased from 76 to 58 % of total area, while forest areas increased from 18 to 24 %, and coffee from 3 to 11 %. Environmental protection legislation, rural credit for smallholder farmers, and demand for agricultural and raw products were identified as main drivers of LULC changes. Projected LULC for 2045 strongly depends on the global socioeconomic pathway scenarios, and forest and coffee areas may increase substantially under strong government measures in the environmentally conscious Green Road scenario or decrease in the high consumption Rocky Road scenario. Our study shows that under the set of drivers during the past three decades reforestation can go hand in hand with increase of agricultural production, but that major and contrasting changes in LULC can be expected depending on the socioeconomic pathway that will be followed in the future. To guide this process, LULC scenarios at the local scale can inform the planning of local and regional development and forest conservation.