土地利用动态监测中多源影像融合方法的比较研究--以陕北黄土丘陵沟壑区为例

在陕北黄土丘陵沟壑区,采用单一传感器的遥感影像提取土地利用信息,存在着识别的土地利用类别少、某些类别混分现象较严重、分类结果的精度较低等问题。以TM多光谱数据和SPOT全色光谱数据的融合为例,提出了适宜于该地区的两种影像融合方法:主成分变换法和乘积运算法,并从影像的光谱质量、纹理信息和目视效果等方面对其进行了对比与评价。结果显示,主成分变换法为较理想的融合方法。以陕北无定河流域为实验样区的土地利用自动分类结果表明,该方法的应用使土地利用各类别的提取精度都有不同程度的提高;水体、水田和城镇用地等面积较小的类别分类正确率提高达到10%以上;坡耕地与林草地的混分明显减少,分类精度均提高了5%以上;分类总精度从82.0%提高到89.2%,取得了良好的分类效果。此研究对于遥感影像融合技术的评价与应用进行了有益的探索,同时为该地区的土地利用动态监测提供了关键技术。     

长时序海量土地利用时空数据统计优化方法

针对任意查询区域年度现状地类面积统计困难、长时序变更流量分析计算耗时等问题,提出基于时空变化图模型的统计优化方法。运用图的连通性原理,对查询统计区域内和边界处的要素实体进行分类,实现了时序快照统计优化算法,解决了任意查询区域时点现状统计困难的问题,提高了时序快照统计的效率。运用多商品流原理进行时空网络图约化性判定,实现了变更流量统计优化算法,减少了要素空间叠置分析次数,解决了长时序土地利用变化变更流量统计耗时问题,提高了统计的效率。最后,以2009—2012年琼海市土地利用数据为例,进一步验证优化算法的有效性和可行性。     

Combining deliberative and computer-based methods for multi-objective land-use planning

This paper reports the outcomes of a deliberative workshop comparing land-use plans proposed by land-manager or domain experts with those derived using a computer-based decision support system (DSS). The DSS integrates four main components, a geographic information system, land-use systems simulation models, impact assessments and land-use planning tools. The land-use planning tools draw on the other components to generate and evaluate alternative patterns of land use and management. Since the land-use planning tools are based on multi-objective genetic algorithms (mGAs) it is possible to generate a range of alternative plans that define the structure of the trade-off between the objectives. The workshop tasked the delegates with specifying land-use plans that achieved the best compromise between two objectives known to be non-commensurable and conflicting. The nature of the best compromise was dependent on their individual perspectives. The delegates proposed allocations both as individuals and in researcher-facilitated sub-groups. The mGA allocations were then compared with those derived by delegates and were found to be broadly similar in performance. Differences in the range of allocations considered feasible were explained by the hard and soft constraints on allocations agreed between the delegates and articulated within the workshop process. The hypothesis that part of the difference in performance between the mGA and delegate allocations was due to the delegates blocking together fields with the same land use for convenience of management was proved. The analysis of the group allocations revealed that the decision-making process had failed to improve on the individual allocations. From these results it was concluded that there was a potential role for mGA based land-use planning tools in researching into, and deliberating on, the possible impacts of policy or other factors affecting land-use systems. It was further concluded that the tools should not be used in isolation since there was the need for stake-holder inputs to adequately define the range of feasible and practical land-use plans.     

A tool for community-based assessment of the implications of development on water security in hillside watersheds

Development and population growth in Latin American countries with steep slope farming are likely to further increase pressures on water and land resources. A methodology was developed for assessing water availability and use under different development pathways at a watershed scale to determine whether water security is a potential problem, and if so, under what conditions it is likely to occur. This methodology makes use of a GIS-based spatial water budget model for simulating stream water availability, water use and stream flow control on a daily basis at a watershed scale. Here, we analysed water availability under three plausible development scenarios for the 3246 ha Cabuyal River watershed in southwest Colombia in the year 2025: Corporate Farming (CF), Ecological Watershed (EW), and Business as Usual (BU). Simulated average river flows at the watershed outlet were, respectively, 874, 796 and 925 l s⁻¹ for the CF, EW and BU scenarios. The contribution of base flow to river flow (base flow index) was on average, 80.8, 85.6 and 77.9%, respectively, for the three scenarios. The watershed had the potential to meet the anticipated increase in water use under each explorative scenario. However, dams were necessary to store irrigation water in the CF scenario, otherwise over 60% of the available water would have been used during the dry season. Such a high figure raises concerns about effects on aquatic and riparian ecology, concentrations of potential contaminants, water reserves for especially low rainfall years, and the watershed resilience to meet temporarily higher water needs during the day. Analyses indicated that current water-use conflicts in the watershed can be resolved if irrigation water supply is separated from drinking water supply. This study helped reduce some of the complexity associated with the interdependencies between land and water resources, the impact of using them, and spatial linkages within the watershed. Results of this study can be used for teaching local stakeholders about basic landscape responses and helping multi-institutional alliances to become proactive and to guide development to the benefit of local communities.     

灌溉试验站的总体规划和观测方法

随着农业产业结构调整的不断深入，传统的灌溉方式已不相适应。为了实现农业用水的高效利用,必须要有科学的灌溉试验成果作依据，做好灌溉试验站的规划建设和观测工作，为真正实现农业用水“总量控制、定额管理”奠定基础。     

绥化市秦家镇农田防护林网络架构及生态农业效益分析

对松嫩平原上一典型土地开发整理项目区深入调查研究基础上,在人均土地面积较少的农村,构建出由农田防护林、水利排灌、道路、农田4项网络构成的高效农田防护林复合经营与多样型林带乔、灌立体混交经营模式,实现了林带由单一结构向多层次的立体结构转移,架构了生态立体农业体系,旨为重新调整土地利用结构,实现山、水、田、林、路的全面治理提供依据。     

阜平县土地资源可持续利用评价

为把握阜平县土地资源的可持续利用程度,该研究以统计数据及TM图片为基础数据源,采用线性加成方法,对阜平县1998～2002年的土地资源可持续利用状况进行了分析评价.结果表明:阜平县土地资源利用可持续性水平逐年提高,可持续利用程度处于基本可持续发展阶段;自然资源因素对现阶段可持续水平的影响最大,但有逐步弱化趋势;未来的可持续发展应主要依靠增加物质投入和科技进步,社会经济条件和生态环境能否明显改善将是左右未来可持续发展的关键.     

湖南省退耕还林工程社会经济效益调查研究

调查结果显示：①农户家庭总收入和净收入退耕后2004年,分别增长41．54％、62．95％,且退耕后农户家庭收入结构也发生了一定的变化;②农户家庭生活和文化消费总支出退耕后2004年增长率分别为37．28％、51．17％,且退耕后农户家庭的生活和文化消费支出结构也发生了一定的变化;③恩格尔系数退耕后2004年下降了3．56％,说明退耕后农民的生活水平得到了进一步提高;④农户家庭就医率和适龄儿童入学率上升到了退耕后2004年的84.5％、97．8％;⑤生态环境建设在我省干部和农户心目中的地住逐渐提高,说明生态环境建设在我省干部和群众中奠定了坚实的民意基础,产生了较为深远的影响力。     

湘西自治州退耕还林工程后续产业调查与思考

退耕还林工程是21世纪一项战略生态工程。作者就湘西自治州退耕还林8年补助期满后农民生计和退耕还林后续产业情况进行了调查分析,并根据退耕还林工程后续管理存在的问题,提出了退耕还林工程后续产业发展应采取的对策。     

不同土层复配方案对土壤水稳性团聚体及有机质的影响

为探究“治沟造地”重大工程项目（GLCP）中新增耕地快速改良的方法,达到营造良好土壤、提升新增耕地生产能力的目的,以延安羊圈沟流域的GLCP为背景,利用马兰黄土（ML）和红黏土（RC）对新造耕地0~30 cm土层进行复配试验。结果表明：当RC为20 cm、ML为10 cm（T3处理）时,复配层土壤孔隙度较对照处理增加了16.7%,容重下降了11.1%。与对照组相比,T3处理0~10、10~20、20~30 cm土层中>0.25 mm水稳性团聚体含量（W_0.25）显著增加,分别增加了11.8、12.3倍和27.9倍;T2（RC为25 cm、ML为5 cm）、T3处理更利于大团聚体的形成,较对照组除在0.25~0.5、0.5~1 mm的粒级有较大增加外,在2~5 mm和>5 mm粒径范围也有明显增加。0~20 cm土层中,即使在考虑对照组前期土壤有机质积累的情况下,T3处理的土壤有机质也与对照组相近甚至更高,且高于其他试验组,表现出更好的有机质赋存能力。T3处理的玉米生长状况较好,其地上生物量最高,较对照组提高了23.9%。研究表明,当复配土壤RC为20 cm、ML为10 cm时,土壤具有最佳的性状和生产力。试验初步证明土层复配是一种可行的快速营造高质量土壤的方法,该方法可为GLCP新造地的改良及类似土地整治工程的实施提供实践参考。