面向农业区划的作物种植结构遥感提取

[目的]尝试将作物种植结构提取结果由行政单元发展为基于相对均质的地理网格单元,解决当前农作物种植结构信息提取的空间局限性问题,文章在大尺度的土地利用/覆被分类与地块尺度的作物分类之间提出了作物种植结构单元概念,并构建了一种快速、低成本、准确的区域尺度作物种植结构提取方法。[方法]利用黑龙江省2014年250m分辨率的植被指数产品构建时间序列曲线提取物候信息,在耕地物候分区基础上对各物候区进行面向对象的多尺度分割,提取作物种植结构单元,利用光谱特征和NDVI指数构建特征空间,最终采用最邻近分类方法提取作物种植结构。[结果](1)利用MODIS时间序列数据提取物候特征进行多尺度分割的方法,能够有效的提取区域尺度农作物种植结构单元;(2)作物种植结构提取总体精度为95.70%;(3)黑龙江省2014年作物种植类型共有12种。其中,三江平原主要是水稻单一种植区、水稻混作区;松嫩平原以玉米单一种植区以及玉米-大豆混作区种植为主;西北部种植结构较复杂;东南部因地势等影响多种植玉米、大豆。[结论]利用物候数据进行种植结构提取可以有效划分农业区划,研究成果不仅为作物种植结构调整和农业发展布局提供科学依据,也是不同区域产量预测的基础,为合理布局农业生产、改进耕作制度以及引入和推广新产品等提供依据。     

基于GF-1与MODIS时空融合的南方丘陵区水稻提取研究

[目的]水稻在我国粮食生产中占有重要的地位,针对南方低山丘陵区地形复杂多样,地块破碎的环境特点,利用遥感数据时空融合方法对水稻分布进行提取研究对作物精准估产和政府决策具有重要意义。[方法]以衡阳县为研究区,基于增强型时空数据融合模型(Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model,ESTARFM)将MODIS数据分别和GF-1WFV、Landsat 8影像进行数据融合,构建高时空分辨率的NDVI时间序列集,对NDVI序列进行滤波并获取各地物物候参数,采用决策树分类方法提取水稻种植面积。[结果](1)ESTARFM能有效融合MODIS和GF-1WFV、Landsat 8影像,其中Landsat 8数据的单波段融合效果(R_(NIR)=0.92,R_R=0.82)优于GF-1WFV融合结果(R_(NIR)=0.82,R_R=0.75),但NDVI结果相关性差异不大(Landsat:R_(NDVI)=0.93,GF-1WFV:R_(NDVI)=0.89);(2)利用决策树分类法进行地物分类,基于GF-1WFV融合数据的分类结果优于Landsat融合数据分类结果,其中GF-1WFV数据得到的分类结果总精度达到86.37%,单、双季稻的精度分别为62.26%与86.70%,Kappa系数达到0.80;而Landsat数据的分类总体精度为80.96%,单、双季稻精度分别为56.87%和70.74%,Kappa系数为0.72。[结论]GF-1WFV融合数据可用于获取精细的水稻种植分布;针对南方低山丘陵区,特别是地形复杂度较高的区域,GF-1 WFV数据比Landsat数据在水稻提取方面更具有优势。     

基于EOS/MODIS数据的南方水稻面积提取技术

该文以我国南方15省、市和自治区为研究区域,采用高时频的EOS/MODIS卫星数据,构建了水稻播种面积识别算法,实现了南方各类水稻(早稻、晚稻和单季稻)种植面积的快速提取。该研究在很大程度上解决了困扰农情遥感监测业务运行中水稻种植面积及其空间分布的难题,可为作物估产、农作物长势以及墒情遥感监测提供基础。     

结合Landsat 8和GF 1数据的冬小麦种植空间分布提取

[目的]为探讨多源中等分辨率数据在冬小麦种植时空分布上的应用。[方法]利用2017年冬小麦关键生育期的Landsat8 OLI(抽穗期)和时间序列的GF-1 WFV(2016—2017生育期)数据,在分析各个行政分区的地表覆盖状况、作物结构和地块破碎度差别的基础上,将行政区划分为3种类型不同的提取单元并建立了适合于各自分区的提取模型:(1)利用关键生育期的OLI数据,采用监督分类—神经网络方法提取结构单一、地块齐整的怀远县种植区;(2)基于WFV数据构建五河县及城区种植区的冬小麦全生育期NDVI时间序列曲线,根据NDVI的时间特征构建冬小麦提取的决策树分类模型提取结构较复杂、混合像元明显的五河县及城区种植区;(3)在对关键生育期OLI-NDVI数据合理分割的基础上,采用最大似然的面向对象分类法获取种植密集、地块破碎的固镇县种植区。[结果]提取结果采用混淆矩阵和当年度统计数据相结合的方法进行精度评价,结果表明:(1)怀远县提取出的冬小麦提取总体精度为97.91%,五河县及城区提取出的精度为97.62%,固镇县的精度为97.42%;(2)全区域冬小麦提取的总体精度为86.82%,Kappa系数为0.84。与当年度统计数据对比的结果表明:2017年蚌埠市的准确提取面积精度可达97.91%,提取面积数据小于蚌埠市统计年鉴提供的统计数据,与调查的实际种植地块基本一致。[结论]采用不同方法提取不同空间分布特征的冬小麦种植面积具有较好的精度,该方法可以为市域冬小麦面积提取提供技术参考。     

基于纹理特征与MODIS NDVI时间序列的耕地面积提取研究

[目的]耕地是粮食安全的重要前提与保障,通过对MODIS时间序列数据的特征分析和提取,讨论了在大尺度条件下的耕地面积提取的可行方法,以期为当地合理利用耕地资源进行农业生产规划与布局提供参考。[方法]文章以呼伦贝尔市为研究区域,选择MOD13Q1为数据源,采用Savizky-Golay滤波方法对MODIS-NDVI时间序列进行滤波处理,并分析各地物间的时间变化特征,最后结合纹理特征信息进行CART决策树分类的结果比较。[结果](1) MODIS-NDVI时间序列能较好的区分不同的土地利用类型;(2) Savizky-Golay滤波降噪能够明显提高分类精度;(3)纹理特征的加入进一步反映地物间差异性;(4)该方法的总体分类精度为83. 72%,Kappa系数为0. 789,其中耕地的提取准确度为86. 33%。[结论]纹理特征使数据像元间的灰度相关性更加丰富,并通过提高像元之间的差异改善结果的精度。该文结果为进一步利用MODIS数据进行土地利用信息与农业资源调查提取提出了新思路。     

21世纪以来江苏省水稻种植面积的变化与启示

目的 研究21世纪以来江苏省水稻种植面积稳中有增的机制，为新时期稳定粮食播种面积保障国家粮食安全提供科学依据。方法 文章采用时间序列描述性统计与区域空间比较分析、因素分解相结合的研究方法。结果 （1）2001—2020年江苏省水稻种植面积经历了“两增两减”的变化，由201.03万hm²波动增长至220.28万hm²，增长9.6%；同期广东、浙江分别减少了53.48万hm²、70.40万hm²，与江苏省水稻种植面积差距不断扩大；（2）2001—2020年江苏省苏南地区水稻种植面积减少了26.94万hm²，苏中地区水稻种植面积基本稳定，苏北地区水稻种植面积增加了45.11万hm²，苏北地区水稻种植面积增加对全省水稻种植面积增长的贡献率达234.2%，是江苏省水稻种植面积稳定的主要原因；（3）水稻生产竞争力不高和有效灌溉面积减少共同导致了苏南地区水稻种植面积的衰减，有效灌溉面积增长是苏中地区水稻种植面积基本稳定的主要原因，有效灌溉面积增加和水稻生产竞争力提升共同促进了苏北地区水稻种植面积的增加。结论 对于拥有较多后备稻田或耕地的区域，在一定时期内区域经济发展不一定导致区域内粮食种植面积的下降，但长期稳定粮食种植面积面临挑战。继续稳定江苏省水稻种植面积需要全省协同努力，苏南地区要稳定并适度增加水稻种植面积，苏中地区要积极探索稳定水稻种植面积的有效途径，苏北地区要着力发展稻米产业经济，探索水稻生产与区域经济协调发展的新路径，同时要高度重视江苏省沿海地区滨海盐土水稻生产的发展，为未来全省水稻种植面积增长开辟新空间。     

时间序列植被指数重构方法比对研究

时间序列植被指数在植被遥感监测中发挥着重要的作用,但其往往存在大量噪声影响,在应用之前需要进行时序植被指数重构。耕地植被指数是进行农作物长势监测与估产以及农业生态系统对气候变化响应等研究的重要工具,本研究借助MODIS植被指数产品,以东北三省耕地为研究区域,针对非对称高斯函数拟合（AG）、双Logistic函数拟合（DL）和Savitzky-Golay滤波（SG）三种常见的时序植被指数重构方法,从原始数据质量对时间序列植被指数重构的影响、不同重构方法对原始数据的保真性和基于不同重构方法的耕地生长季长度空间格局等方面进行了对比分析。首先对NDVI及其质量控制数据进行分析,探讨原始数据质量对时序植被指数重构的影响;然后选择若干随机抽样点,从定性和定量两个角度来评价不同方法对时序植被指数的重构效果;最后借助研究区的耕地物候特征,间接对不同的时序植被指数重构方法进行对比。结果表明,在东北三省利用这三种方法进行耕地时序植被指数重构时需要引入质量控制数据,AG拟合和DL拟合在该地区耕地时序植被指数重构时表现相似且比SG滤波更加适宜。     

基于MODIS时序数据分析的作物识别方法

通过对植被指数序列数据分析可以准确提取农作物的物候特征信息,从而对不同作物进行识别。该文利用MODIS2004年以旬为单位合成的NDVI数据,采用Coif4小波变换的方法重构作物生长曲线,运用快速傅里叶变换对NDVI时序曲线进行分析,选取曲线均值(0级谐波振幅)、1~3级谐波的初始相位及振幅比例作为作物识别的参数,实现华北地区5种主要作物的识别。经过验证,最终的使用者精度都达到85%以上。     

利用高空间分辨率遥感数据的农作物种植结构提取

农作物种植结构是掌握粮食种植面积和产量的重要前提,也是进行作物结构调整与优化的依据。该研究以黑龙江肇东市为研究区域,以高空间分辨率RapidEye影像为遥感数据, 基于最大似然监督分类方法提取了肇东市2011年农作物种植结构空间分布,利用地面样方调查数据进行了线状及细小地物扣除系数计算,实现遥感提取的农作物种植面积的精细提取,然后从面积数量和空间位置两个方面对遥感提取的农作物种植结构进行了精度评价。研究结果表明,利用RapidEye数据提取的农作物种植面积数据总体精度为97.00%,位置精度为96.15%,高空间分辨率数据在农作物种植结构遥感提取中具有重要潜力,线状及细小地物扣除系数可以有效减小线状及细小地物对高分提取的农作物种植结构的精度。     

水稻空间分布遥感提取研究进展与展望

水稻是我国三大粮食作物之一,其空间分布受自然条件和农业发展状况的影响,变化显著。研究水稻空间分布遥感提取是当前农业土地变化科学的热点和难点。通过对国内外研究的回顾,该文系统归纳了近年来水稻空间分布遥感提取的数据源、特征量及分类算法最新研究进展,并对其未来研究方向进行初步探讨。首先从遥感数据源方面,水稻面积监测主要采用多光谱光学影像,同时高光谱数据和雷达数据也正逐步推广应用。其次从遥感分类方法及其对应的特征量方面,包括监督和非监督分类、智能化分类算法（神经网络、支持向量机、决策树及随机森林算法）、面向对象分类、多时相植被指数法及综合提取算法等分类方法,其主要对应的特征量各有差异。最后,结合我国水稻空间分布遥感提取的实际状况,提出构建全国长时间序列水稻物候历和高时空分辨率时序NDVI数据集,大力发展基于多时相遥感分类方法和建立分层的面向对象分类方法,以及加强水稻种植北界、种植重心迁移等动态变化监测研究的建议,推动我国水稻遥感动态监测和农业土地变化科学的发展。     

The Effect of the Structural Adjustment Program on the Output,Prices and Exports of Major Agricultural Export Crops in Nigeria

The primary objective of this paper is to examine changes in the level of output, prices and exports of major export crops resulting from the Structural Adjustment Program (SAP) in Nigeria. THere two main sources of data: the Central Bank of Nigeria (CBN) through its annual reports, Economic and Financial Review, and the Nigerian Federal Office of Statistics (FOS) through its Trade Summaries. Although the SAP led to appreciable increases in output and producer prices, its effects on exports were insignificant. The implications of these for the implementation of the program are explored.     

Application of an ecosystem function framework to perceptions of community woodlands

Owners, local residents, government, and conservation organisations can express divergent preferences in the development and management of local woodlands. The perceptions of these four groups were examined, in the context of three community woodlands in Eastern England, using an ecosystem function framework. In a pilot study, residents were able to allocate a relative importance to woodland ecosystem services which were then related to “regulation”, “habitat”, and “production” or “information” functions. However residents also placed importance on negative services or “dis-services” associated with the woodland ecosystem. Therefore a fifth category of “dis-services” was included in the main survey which included 84 local residents, three woodland owners, three government institutions, and six representatives from conservation groups. Each of the four groups placed greatest importance on services associated with habitat (16–39% of the total importance) and information (30–50%) functions suggesting, in this example, mutual interest in the use of woodlands as a habitat or recreational resource. By contrast a potential area of difference was the particularly high importance placed by one owner on dis-services such as fly tipping. In addition the woodland owners placed higher importance (10–20%), than local residents and conservation groups (7–9%), on the productive services of the wood. This suggests a need for communication when production-related operations affect recreation. The ecosystem function framework appears to be a useful approach for highlighting potential tensions and areas of mutual interest in the management of semi-natural ecosystems.     

土地学科的建设和发展——"土地学科发展规划研讨会"综述

中国土地科学学科发展已取得很大成就,表现为专业教育和人才培养成绩突出、初步形成学科体系、取得大批研究成果.而存在的问题主要是基础理论研究欠缺、独特的土地科学研究方法体系尚未形成、研究角度单一、学术交流质量不高和学科带头人的影响力不足.土地科学学科发展目前面临着巨大的机遇和挑战,应明确土地科学学科发展的基本思路、发展目标及2010-2020年的主要建设任务和保障措施.     

Revealing different understandings of soil held by scientists and farmers in the context of soil protection and management

This paper aims to analyse and draw together results from similar studies in England, Switzerland and France which investigated farmers’ understanding of soil and compared it with that of scientists, researchers and advisors (collectively called scientists in this analysis). A range of methods were used across the three studies and different theoretical approaches, looking at forms of knowledge, local practice of knowledge production and conceptions of reality, were employed to explain the results. Despite the different contexts, methodologies and theoretical approaches in the three studies, the results reveal similar patterns of difference in farmer and scientist understanding of soil. In the English study, farmers demonstrate a ‘know-how’ form or intuitive working knowledge of soil while advisors rely on scientifically established forms of ‘know-why’ and seek to understand and explain soil processes. Similarly in the Swiss study farmers’ and scientists’ differing perceptions are directed and shaped by their respective aims, methods and context of work. In the French study, farmers and researchers are shown to have different conceptions of soil, they attribute different meaning to the same activities, and use different words and language to describe the same features. In all three studies understanding is shown to be cultural and contextual, as such an integrative theoretical framework is proposed.     

An evaluation framework for earthquake-responsive land administration

In recent years earthquakes and their secondary hazards have claimed the largest number of lives of all large natural disasters. Some of the world’s most earthquake-prone zones are also areas of high population density. The impact is magnified by vulnerability factors including non-enforcement of building codes, knowledge gaps, urban poverty and poor governance capacity to manage and reduce earthquake risks. Poor security of land tenure and property rights increases the vulnerability of people and affects their ability to respond to natural disasters.Earthquake recovery and reconstruction provides very significant challenges for land agencies, with these challenges differing from one country to the next due to differences in the local context. Drawing on contrasting case studies in Haiti, Nepal and New Zealand this paper identifies the common post-earthquake land administration functions and challenges that may apply to many contexts. These lessons provide land agencies and other key stakeholders with a summary of the challenges an earthquake poses for land administration at different post-disaster stages. We also discuss the policy and regulatory, institutional, operational and preparedness lessons for land administration. From these lessons we propose a framework for evaluating the earthquake-responsiveness of a land administration system. This framework can be used by a land agency in an earthquake prone region, or where an earthquake has recently occurred, to assess what challenges to land administration might occur in the event of an earthquake, and the preparedness of their land administration system.     

森林生物多样性评价模型的改进

针对2002年的评价模型中的不足,提出了新的改进后的森林生物多样性变化的评价模型,并在我国第六次森林资源清查(1999～2003)资料的基础上,对1973～2003年我国森林生物多样性的变化进行了补充评价。评价结果表明:我国森林生物多样性的压力越来越大,压力指数由1973年的100,上升到2003年的199.10,上升了1.99倍;森林物种多样性总体的下降趋势已有一定幅度的改变,森林物种多样性指数增加了31.12%。森林生态系统多样性和森林生物多样性先逐渐上升,尔后又下降,第六次森林资源清查时又有所恢复,并分别上升了4.67个百分点和17.90个百分点。     

Evaluating Alternative Policy Responses to Higher World Food Prices: The Case of Increasing Rice Prices in Madagascar

Higher world food prices have led many developing countries to adopt policies to mitigate the impact on low-income households. This article sets out a partial equilibrium framework to evaluate the efficiency, distributional, and revenue implications of alternative policy responses. The model is applied to evaluate tariff reductions and targeted transfers in Madagascar. Although lowering tariffs generates substantial efficiency gains, these accrue mainly to the top half of the welfare distribution, and poor net sellers are actually worse off. Developing a system of targeted direct transfers to poor households is likely to be a substantially more cost-effective approach to poverty alleviation.     

转变地质工作发展与服务方式的实践和建议

天津市地矿局注重加快转变经济发展方式,发挥地质工作优势,推进低碳清洁能源的开发利用创新和技术进步,紧紧依托地质工作的人才、技术和行业优势,加大清洁环保资源的勘查、研究、开发、利用。针对天津市水资源缺乏的情况,积极加强后备和应紧水源勘查。按照“两种资源,两个市场”的思路,通过实施中外合作勘查项目,以境外勘查工作为载体和平台,实施引进来和走出去战略,为天津市经济社会发展提供地质技术支撑。     

Trust-A monolithic panacea in land use planning?

Although trust research has been extensive and substantial, the constitution and actual merits of trust in land use planning remain nebulous. What do participants of a local land use planning process actually mean when they say they trust the planning committee? How important is participants’ trust in the planning committee in shaping their perceptions of the planning process and their cooperation in it? To explore the everyday meaning of trust in the specific context of local land use planning, semi-structured interviews with the participants of a local planning project in Switzerland were conducted (n = 9). Based on these results, the constitution and the relevance of trust in the responsible planning committee among a wider circle of participants were assessed (n = 66). The results show that participants trust the planning committee if they perceive its members as competent, honest, open, fair, reliable, reciprocating, respectful and committed. Interestingly, a considerable part of trust in the planning committee hinges explicitly on whether the committee incorporates the personal interests of the participant. Trust is indeed vital to participants’ belief that a meaningful discussion and cooperation with the members of the planning committee is possible. However, trust is neither a guarantee for people's approval of planning decisions nor for their cooperation. One implication of the findings is that in order to evaluate trust-building practice comprehensively, it is necessary to first understand the specific everyday meaning of trust for ‘real people’ in real planning processes.     

Agrarian Poverty,Nutrition and Economic Class – A Study of Gujarat,India

This paper analyses poverty and calorific undernourishment in the Indian state of Gujarat, where high and market‐led industrial growth has resulted in rapid economic improvement. The study is carried out through a combination of secondary and survey‐based data. We conclude that the neoliberal agenda of uncontrolled, outward‐looking growth has not resulted in significant reduction of poverty or malnourishment in rural areas. Furthermore, while land ownership is officially used as a proxy for wealth distribution, class position appears a better predictor of poverty status in the rural areas than landownership per se. At the policy level, there is a need to revive the agrarian economy and create new non‐agricultural assets, and the primary focus in the state must shift to the distribution of created assets rather than a single‐minded focus on growth.