基于GIS运用对旅顺口区农用地分等定级研究

以旅顺口区土地利用现状图、土壤图、地形图等图件资料和土地自然质量、土地利用、土地经济相关统计资料为基础,运用GIS软件的空间叠加分析功能、属性查询功能和制图技术对旅顺口区农用地分等定级进行研究。在进行分等定级研究工作中,运用叠置法划分分等单元;采用特尔斐法确定分等因素及其权重大小;利用指定作物来计算土地利用系数和土地经济系数;在划分农用地等别时使用等间距法,最后生成农用地自然质量等别图、利用等别图和经济等别图。最终获得的旅顺口区农用地分等结果显示,旅顺口区自然质量等为8等至12等,共5个等别,其中11等占参与农用地分等总面积的40.79%,10等占38.79%,8等、12等、9等次之;利用等为11等至13等,12等所占比例最大,达到80.38%,13等最少;经济等别分为12等地和13等地,12等占绝大部分;由此得出旅顺口区农用地等级水平处于中低水平。     

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。     

福州市饮用水源保护区水土流失风险评价

选择植被覆盖度、地形坡度和土地利用类型来进行水土流失的风险度评价;试验区域为福州市第二饮用水源地山仔库区和塘坂库区;利用Landsat-7ETM 的影像,在计算归一化差分植被指数NDVI的基础上估算水源地保护区的植被覆盖度;利用栅格数字高程模型DEM,计算地表坡度;利用土地利用类型图获取保护区各地土地利用类型的分布;根据水利部部颁标准,对植被覆盖度、坡度和土地利用类型进行分级,建立水土流失风险评价模型,并在ArcGIS 9.0软件支持下,对上述各因子进行叠加分析,得到保护区水土流失评价风险评价;结果表明研究区内生态环境总体保护较好,但存在一定的水土流失现象,生态环境保护还需进一步加强.     

河北省张宣葡萄产区土壤地球化学特征

[目的]为科学合理规划特色农产品种植区,因地制宜地扩大张宣葡萄种植规模。[方法]文章通过对张宣葡萄产区开展1:5万农业生态地质现状调查,利用土壤地球化学测试数据,与河北省平原区背景值、张家口盆地背景值进行对比分析,归纳总结研究区土壤地球化学特征;并依据土地质量和土壤环境质量相关规范,对张宣葡萄产地进行系统地土壤肥力和土壤环境质量评价。[结果]葡萄种植区土壤中铜、锶、二氧化硅、氧化钾含量较高,尤以铜最为显著,含量均值是张家口盆地背景值的2倍,是河北省平原区背景值的1. 94倍;铬、镍、铁、锰、氮、有机碳、硒、镁含量相对较少,均低于张家口盆地背景值和河北省平原区背景值。整体而言,土壤综合肥力相对缺乏,主要表现为氮、磷缺乏;土壤环境综合质量较为清洁,无Ⅲ类区,全部重金属元素均未超风险管制值,99. 26%的面积低于全部重金属元素风险筛选值,表现为4个样点铜含量和1个样点镉含量高于风险筛选值,分别位于宣化区和涿鹿县境内。[结论]应通过增施化学肥料提高土壤中氮、磷含量,注意防治保护性杀菌剂的使用带来的铜局部累积现象。     

Regional erosion risk mapping for decision support: A case study from West Africa

Effective soil and water management strategies require regional-scale assessment of erosion risk in order to locate prioritized area of intervention. Our study focuses on the Atacora mountain and surrounding areas (covering more than 18% of the total land area of Republic of Benin) which face a serious erosion threat despite their ecological and economic importance. To appraise the level of soil erosion risk of large area, we rely on the Instituto Nacional para la Conservación de la Naturaleza (ICONA) erosion model and use data from geographic information system (GIS). The erosion risk model requires four main inputs, namely, information on slope, lithofacies, land use and vegetation cover. The slope layer computed from ASTER digital elevation model (DEM) and the lithofacies layer inferred from digital pedogeological map are combined to draw soil erodibility map. To build soil protection map, we use land use/land cover layer extracted from LANDSAT 7 ETM + images in addition to vegetation cover layer derived from MODIS NDVI product. The final erosion risk map (with a resolution of 1 arc second) is obtained by overlapping erodibility and soil protection maps. We find that 21.8%, 58.5%, and 19.5% of the study area presents very low to low, medium, and high to very high level of erosion risk, respectively. Moreover, our findings are aggregated at the district-level (administrative unit). We observe that erosion risk is more acute in Boukoumbe district. Kerou, Kobli and Natitingou districts are mildly affected by erosion risk, while Kouande, Materi, Pehunco, Tanguieta and Toucountouna districts face a low risk. Ultimately, the proposed erosion risk map can help researchers and decision makers design and implement effective soil and water management interventions in the study area.     

Measuring soil quality dynamics A role for economists, and implications for economic analysis

Measuring soil quality is extremely difficult, yet it has clear economic importance. In particular, there is a great deal of empirical interest in the dynamics of soil quality evolution when land managers respond to policies and other incentives. Yet current methodologies for measuring changes in agricultural land quality are largely static and rely heavily either on incomplete measures such as proxy variables, or ad hoc indexes of selected soil characteristics. Moreover, much empirical work relies on static econometric techniques or simulation models. In this paper, we develop a means to infer soil quality changes from input and output data using a dynamic production function model. Using data from field experiments, we estimate the model in a way that allows the recovery of a dynamic measure of soil quality whose evolution depends on variations in management practices. Our methodology and findings will help provide firmer empirical foundations for analyses of the economic implications of land degradation and the soil quality implications of agricultural policies.     

The Economic Value of Soil Quality under Alternative Management in the Canadian Prairies

This paper describes a dynamic simulation model that integrates environmental and economic components of agricultural crop production systems to predict changes in soil quality and the concomitant impact on economic returns. The model is used to simulate crop yield, soil quality and economic performance of a conventional crop rotation and several alternative crop rotations in two contrasting environments in western Canada over a 50-year period. This information is used to quantify the impact of the crop rotations on soil organic carbon (SOC) and the economic value of on-site SOC changes. The estimated value of these impacts range from $0.20/t to $2.10/t of SOC/ha/yr.     

Population pressure and soil quality in Sub-Saharan Africa: Panel evidence from Kenya

Population pressure on farmlands can have two opposing effects on soil quality. It can negatively affect soil quality due to more frequent and intensive use of farmlands, but also can induce transition of farming methods towards more intensive farming in which more fertilizer and improved seeds are used in order to make smaller farmlands more productive. In Sub-Saharan Africa, the net effect is likely to be negative given the region’s current low fertilizer use. Recent studies, however, show evidence of agricultural intensification in regions with high population pressure. It is important to analyze the extent and speed of soil degradation and its relationship with population pressure. Nonetheless, empirical studies on this topic are almost non-existent, partly because soil quality is shaped over a long time horizon, and quality panel data on this issue are rare. We use unique panel data for rural households containing soil quality information from Kenya to elucidate the effect of population pressure on soil quality. We find that population pressure reduces soil quality and also induces agricultural intensification. This suggests that although farmers are trying to mitigate the negative effect of population pressure on soil quality, the rate of soil degradation is outpacing that of intensification.     

Valuing soil conservation benefits of agroforestry: contour hedgerows in the Eastern Visayas,Philippines

Trees can be considered as investments made by economic agents to prevent depreciation of natural assets such as stocks of top soil and water In agroforestry systems farmers use trees in this manner by deliberately combining them with agricultural crops on the same unit of land. Although advocates of agroforestry have asserted that soil conservation is one of its primary benefits, empirical estimates of these benefits have been lacking due to temporal and spatial complexity of agroforestry systems and the nonmarket aspect of soil capital assets. This study designs and applies a bio-economic framework for valuing the soil conservation benefits of agroforestry. The framework is tested with econometric analysis of data from surveys of households in Eastern Visayas. Philippines, where USAID/Government of Philippines introduced contour hedgerow agroforestry in 1983. By constructing a weighted soil quality index that also incorporates measures of soil fertility, texture and color in addition to erosion, we extend previous economic studies of soil resources. This index is regressed on a variety of farming and site specific bio-physical variables. Next, we use a Cobb-Douglas profit function to directly relate agricultural profits and soil quality. Thus, the value of soil conservation is measured as a quasi-rent differential or the share of producer surplus associated with a change in soil quality. Because this framework assumes the existence of markets, the assumption is tested by analysing the statistical significance of consumption side variables, e.g., number of household members, on production side variables, e.g., profits. Instrumental variables are used to handle the endogeneity of the soil index in the profit equation. Seemingly unrelatedregression (SUR) analysis is used to accommodate correlation of errors across the soil and profit equations. Regression results reveal the importance of agroforestry intensity, private ownership, land fragmentation, and familiarity with soil conservation as positive covariates of soil quality. Analysis of production data indicate the importance of market prices, education, farming experience, farm size, topography, and soil quality as positive covariates of household profits Investments in agroforestry to improve or maintain soil capital can increased annual agricultural profits by US$53 for the typical household, which is 6% of total income. However, there are significant up-front costs. Given that small farmers in tropical uplands are important players in the management of deteriorating soil and forest resources, policy makers may want to consider supporting farmers in the early years of agroforestry adoption.     

Application of spatial resource data to assist in farmland valuation

A land transaction is generally not a recurring action for most buyers and sellers, their experience and knowledge are limited, for this reason the services of property agents and valuers are sometimes used, just to get more information available. The condition of insufficient information and the inability to observe differences in land productivity gives rise to the undervaluation of good land and overvaluation of poor land. The advent of the Internet made access to comprehensive information sources easier for property agents and valuers whose critical time and resources can now be effectively managed through Geographic Information System (GIS) integrated workflow processes. This study aims to develop the blueprint for a farm valuation support system (FVSS) that assists valuers in their application of the comparable sales method by enabling them to do the following: (1) Rapid identification of the location of the subject property and transaction properties on an electronic map. (2) Comparison of the subject property with the transaction properties in terms of value contributing attributes that can be expressed in a spatial format, mainly (a) location and (b) land resource quality factors not considered in existing valuation systems that primarily focus on residential property. An algorithm, that generates an index value, was developed to allow easy comparison of the land of a subject property and that of transaction properties. This index value distinguishes the proposed FVSS from other existing property valuation systems and can therefore be used by valuers as a first approximation of a property's soil suitability, before doing further field work. The FVSS was successfully developed and tested, primarily using data obtained in the Western Cape, South Africa.     

Creating Value in the Supply Chain for Australian Farmed Barramundi: Whole of Chain Perspective

This article investigates 4 key areas of supply chain management to identify opportunities to create value for Australian farmed barramundi. These key areas are product attributes, material flow, information flow, and relationships. This exploratory study forms the first stage of a value chain mapping study. Based on data gathered from 13 in-depth interviews, 7 with farmers and 6 with wholesalers/retailers, a preliminary map of the value chain for Australian farmed barramundi was developed. From a producer perspective, 3 key issues emerged: lack of collaboration, inconsistency of product quality, and lack of knowledge of what consumers value. Although wholesalers/retailers identify product consistency as a key issue, they further identify product dumping and the growth of imports as areas of major concern. These findings laid the foundation for strategy development at both the individual and industry level. The insights from this case highlight the value of chain analyses as a diagnostic tool for strategy development.     

Investment in site-specific crop management under uncertainty: implications for nitrogen pollution control and environmental policy

This paper applies an option‐pricing model to analyze the impact of uncertainty about output prices and expectations of declining fixed costs on the optimal timing of investment in site‐specific crop management (SSCM). It also analyzes the extent to which the level of spatial variability in soil conditions can mitigate the value of waiting to invest in SSCM and influence the optimal timing of adoption and create a preference for custom hiring rather than owner purchase of equipment. Numerical simulations show that while the net present value (NPV) rule predicts that immediate adoption is profitable under most of the soil conditions considered here, recognition of the option value of investment indicates that it is preferable to delay investment in SSCM for at least 3 years unless average soil quality is high and the variability in soil quality and fertility is high. The use of the option value approach reveals that the value of waiting to invest in SSCM raises the cost‐share subsidy rates required to induce immediate adoption above the levels indicated by the NPV rule.     

Proposed algorithm for the identification of land for consolidation with regard to spatial variability of soil quality

The quality of soil is one of the most significant factors having a real impact on the potential level of agricultural crops. Therefore, it is a significant element shaping the profitability of agricultural production in the specific area. Familiarity with spatial variability of soil quality classes in respective voivodeships has an impact on planning the development of agricultural areas and effective allocation of money to rural spatial restructuring. This element also provides important information in the process of consolidation works programming which takes place at the regional government level. This data is characterised by very long usability due to a small number of changes referring to classification of land entered into the land and building survey. Data on the quality and suitability of soil in the analysed area was acquired from the analysis of data from the land and building survey. Analyses were carried out in 3 poviats of Lublin voivodeship located in the eastern part of Poland covering an area of 501 132.9 ha, split into 610,160 plots. This paper presents an algorithm designed by the author for identifying areas in which land consolidation works should be performed, including its practical application using the adopted sample. The algorithm identifies areas characterised by the highest soil quality, which makes it possible to indicate areas where land consolidation work should first be undertaken.     

全国农业资源一张图研制技术探讨

目的 文章围绕全国农业资源一张图生产需求,借助空间大数据处理技术,研究利用2018年度全国土地变更调查县级成果,加工全国及82个绿色农业先行示范区耕地、草地、水域农业资源空间分布图的关键技术和方法,探索全国农业资源一张图生产技术流程。方法 需求分析和软件研发相结合。结果 基于全国统一地理网格框架,设计由2 880个县级土地利用数据库生产集成化全国耕地、草地、水域空间分布栅格图的技术流程,并开发了一体化处理软件平台,形成了全国、2个省、11地市、69县区多尺度耕地、草地、水域等农业资源一张图。结论 综合采用现代空间信息集成技术,利用国家年度土地变更调查县级土地调查数据快速生产全国农业资源（耕地、草地、水域）一张图栅格数据的技术路线可行,且产品质量可靠,可为全国农业资源管理提供较好的基础数据支撑。     

北京市耕地生态价值评估与时空变化分析

[目的]合理测算北京市耕地生态价值,分析区域内部生态价值差异和变化规律,为区域耕地保护和多功能利用奠定基础。[方法]基于北京市耕地利用数据,结合生态经济学原理与方法,确定了包括气体调节功能、净化环境功能、涵养水源功能、固土保肥功能和营养物质循环功能在内的耕地生态价值的类型,采用影子工程法、机会成本法和替代成本法等方法,构建了不同功能的评估模型,并以北京市1980年、1995年、2000年和2013年的土地利用现状图为基础,对4期耕地生态价值进行了评估,分析了其空间分布状况。[结果]1980~2013年,耕地生态价值从远郊区到中心城区逐渐降低,1980~2013年,耕地生态总价值由1980年的122.54亿元减少到1995年的94.27亿元,后增加到2000年的102.72亿元,到2013年又减少到76.90亿元;各区耕地生态价值都呈现了明显的下降趋势,不同区耕地生态价值变化规律有所不同。[结论]研究结果为区域耕地保护和多功能利用奠定了基础,也为制定生态补偿政策及确定生态补偿标准提供了参考。     

峡江县森林涵养水源和保育土壤价值核算

以最新发布的《中国森林生态系统服务功能评估规范》为依据,根据2009年峡江县二类森林资源调查资料,对峡江县森林生态系统的涵养水源(调节水量、净化水质)、保育土壤(固土、保肥)等生态服务功能价值进行初步核算,核算结果,峡江县森林生态系统涵养水源价值为30.55亿元/a,保育土壤价值为872.64万元/a。     

吉林省1996—2005年土地生态系统服务功能价值变化分析

依据吉林省1996-2005年土地利用变更调查数据和行政区划图,参照我国陆地生态系统单位面积服务功能价值表,采用Costanza和谢高地等的方法模型估算了各种生态系统服务功能价值,并分析了其空间分布特征。结果表明:研究期间土地生态系统服务功能价值增长56842.58万元,其增长来自林地和水体生态服务价值的增加,其中林地贡献较大;而耕地、牧草地和湿地生态系统服务功能价值的下降则是土地生态系统服务功能价值降低的主要原因在空问分布上,长春市各县(市、区)均为负增长,其余各市(州)分布离散,无明显地域集聚特征;土地生态系统服务功能价值变化与社会经济发展水平呈现一定的相关性,主要表现为全省7个地级市区均呈负增长。     

Challenging Small‐Scale Farming: A Non‐Parametric Analysis of the (Inverse) Relationship Between Farm Productivity and Farm Size in Burundi

We use a non‐parametric approach to investigate the (inverse) relationship between farm productivity and farm size. A kernel regression is used on data of mixed cropping systems to study the determinants of production including different factors that have been identified in literature as missing variables in the testing of the inverse relationship such as soil quality, location and household heterogeneity. Household data on farm activities and crop production were gathered from 640 households in 2007 in two Northern provinces of Burundi. Our results do not reject the findings of an inverse relationship between farm size and productivity. However, we find that size returns vary substantially with farm size, that is, between 0.2 for the smallest farms and 0.8 for the largest farms. Other factors that significantly affect production include soil quality. Finally, we find a significant positive association between food security and farm size.     

东北黑土区设施栽培对土壤养分的影响——以哈尔滨地区为例

设施蔬菜土壤养分是制约蔬菜生长及品质的关键因子,迄今有关东北黑土区设施栽培对土壤养分的影响的研究鲜见报道。本研究以哈尔滨市为研究区,通过调查取样,分析了黑土区设施蔬菜栽培土壤的碱解氮、速效磷、速效钾、有机质和pH的丰缺程度,比较了设施蔬菜土壤与露天蔬菜土壤的养分含量。结果表明:(1)设施蔬菜土壤的碱解氮含量处于亏缺状态,其他土壤养分含量均处于高水平状态。(2)哈尔滨市设施蔬菜土壤养分含量均较露地蔬菜土壤高。碱解氮、速效磷和速效钾含量起初随着设施使用年限的增加而增加,到第8年达到最大值,随后开始降低。土壤有机质的含量到第8年达到最大值,随后开始降低。土壤pH随设施使用年限的增加起初变化不大,到第8年明显降低,达到最低值,之后又有所上升。(3)哈尔滨市区内的设施蔬菜土壤速效磷含量高,外县的设施蔬菜土壤碱解氮、速效钾和有机质含量高,郊区的设施蔬菜土壤碱解氮、速效磷、速效钾及有机质的含量均最低。本项研究表明,设施栽培使哈尔滨地区土壤速效养分及有机质含量发生明显变化,且随着地区不同而差异明显,土壤养分含量随设施使用年限而变化,使用8年的设施菜地土壤中pH值最低,碱解氮、速效磷、速效钾及有机质含量最高。     

基于GIS的金沙江流域耕地地力评价——以云南省绥江县为例

为掌握金沙江流域耕地地力基本情况,科学指导农业生产,以云南省绥江县为例进行耕地地力评价研究。文章采用GIS技术,利用土地利用现状图、土壤图及行政区划图叠置划分法确定评价单元,选取土壤管理、立地条件、剖面与耕层理化性状等16个评价因子,采用模糊数学理论确定指标隶属度,借助层次分析法对评价单元的指标隶属度进行加权求和计算耕地地力综合指数,运用累积曲线法将绥江县耕地划分为6个等级,其中,1级耕地630.69hm~2、2级耕地477.14hm~2、3级耕地2 092.64hm2、4级耕地1 594.71hm~2、5级耕地3 231.31hm~2、6级耕地2 315.04hm~2,分别占总面积1.034 153万hm2的6.10%、4.61%、20.24%、15.42%、31.25%、22.38%;同时,将绥江县中低产田地划分为3种类型,其中,旱耕地坡地梯改型5 974.55hm2、旱耕地瘠薄培肥型1 296.94hm~2、稻田渍涝潜育型387hm~2,分别占总面积的57.77%、12.54%、3.74%。并针对影响耕地质量的障碍因子提出改良利用建议。