An eco-balance approach to the evaluation of historical changes in nitrogen loads at a regional scale

Historical changes in nitrogen flows of a municipality from 1912 to 2002 were analyzed to evaluate the relation between production and environmental pollution. The system comprised human, livestock and farmland subsystems. The indicators used in this study were production, surplus nitrogen (N) on farmland and total systems, and flow indices. Flow indices consist of cycling index (CI), export index (EI), and loss index (LI). CI was defined as the proportion of nitrogen cycled in the system to the total system throughflow, EI as nitrogen exported from the system, and LI as nitrogen lost from the system (sum of field surplus nitrogen, nitrogen in non-utilized excreta, and N₂O and NH₃ emissions).     

Poverty and biodiversity trade-offs in rural development: A case study for Pujiang county,China

Both, poverty reduction and preservation of biodiversity are high on the global agenda on sustainable development. The relationships between poverty, biodiversity of agro-ecosystems and agricultural development are complex and poorly understood. In this paper, we present an integrated framework for analysis of agricultural development and natural resource management options at agro-ecosystem level, using Pujiang county, in Zhejiang province, China as a case study area to perform the analysis. A regional linear programming (LP) model is applied, maximizing regional economic surplus, given production and labour market conditions in Pujiang. We use the model to examine the consequences for a set of regional poverty and biodiversity indicators, of four so-called poverty reduction strategies, i.e., (i) intensification of production, (ii) diversification towards livestock production, (iii) land expansion, and (iv) an exit from agriculture. The analysis indicates that diversification is the most promising poverty reduction strategy, but requires efficient use of animal manure in cropping systems to avoid environmental problems. Improved nutrient management in cropping systems is effective in reducing the regional nitrogen surplus, but less effective in increasing per capita income. The exit strategy is effective in reducing poverty and achieving biodiversity goals, but may have important social consequences that are not addressed in this study. Further reduction in rural poverty is hampered by labour constraints during the harvesting period in high value crops such as vegetables and fruits, which calls for research and development in the field of agricultural mechanization.     

论干旱区水资源与生态环境问题

本文以我国西北和中亚地区（哈萨克斯坦南部）为主，论述开发利用水资源过程中所出现的生态环境的变化，探讨合理开发、利用水资源与生态环境的关系。     

果树对光环境变动的生理响应

叶片光合作用是果树产量和品质形成的基础,我国目前90%的苹果园采用乔砧密植栽培模式,树冠郁闭,内膛光照恶化,产量品质下降,成为制约我国苹果品质提升和产量增加的重要瓶颈。该文综述了果树栽培生理过程中光环境变动的重要意义,分析了光照强度、光质和光环境变动对叶片功能和光合生理的影响,介绍了目前光合作用分析技术的新进展,并对未来果树对光环境变动生理响应方面应该开展的研究内容进行了阐述,以期为揭示果树适应动态光强的机理以及我国现阶段乔砧密植果园树形改造提供理论依据。     

助剂在除草剂应用中的作用及发展前景

对助剂在除草剂中的应用历史、国外现状、发展趋势进行了综述。主要内容有助剂在除草剂中的作用,如抗飘移、兼容、沉积、去泡、水质调节等及相应的助剂品种;按来源和化学结构,助剂的类型有表面活性剂类、油类、无机盐类等,这些助剂对除草剂活性提高都有促进作用。文中指出了生物源、环境相容性、低水生生物毒性、易降解、对作物没有毒害的高效新型助剂是助剂开发的方向,并介绍了部分国外新品种;作者还对我国应采取的对策提出了建议。     

豆科植物和根瘤菌在生态环境中的地位和作用

随着我国人口的增加和城市化进程的加快,人类对土地资源的需求不断增加,土地使用的透支趋势明显;另一方面大量使用农用化学物质,对生态环境的胁迫增大。豆科植物在根系中因其可与根瘤菌共生形成特殊结构---根瘤,具有生物固氮作用而受到广泛关注。种植豆科植物,利用豆科植物和根瘤菌形成的共生固氮体系可以减少氮肥的投入,增加土壤的有机质含量,改善土壤生态环境,是一种天然的利于生态环境的农业生产方式。本文介绍了豆科植物和根瘤菌的一些重要特征,论述了豆科植物与根瘤菌共生的关系,表明发展豆科植物对于生态环境的修复、维持土地的生产力以及节能减排方面的重要作用,以期为改善生态环境提供一些可参考的方法和依据。     

因应全球气候变化的高校环境意识教育策略

介绍了环境意识的内涵及因应气候变化大学生环境意识培养的意义,从提高环境意识的知识基础、培养环境价值观、环境伦理内容教育、环境负责任教育几方面构建了因应气候变化的大学生环境意识教育体系,提出了因应气候变化的大学生环境意识培养途径,包括开设环境意识教育公共选修课,将环境意识内化于专业教学中,引导高校环保社团发展,开展环境保护校外宣传与实践。     

变化环境下干旱牧区水资源草地资源及其承载力研究进展

介绍了近年来国内外在环境变化对水资源、草地资源及其承载力的影响方面的研究现状及进展,阐述了研究气候变化及人类活动对水资源与草地资源及其承载能力影响的方法,指出了研究中存在的问题,分析了干旱牧区在该领域未来研究的发展趋势.     

资源环境约束下的农业可持续发展问题研究——以新疆为例

立足于新疆自然资源特点,探讨新疆农业发展现状和可持续发展过程中存在的问题,如农业产业结构单一,区域发展不平衡;生产格局分散、小规模化比较明显;农业用水效率较低,开发利用不合理。然后,针对制约农业可持续发展的主要资源环境因素,提出新疆农业可持续发展的主要措施,如调整农业产业结构,进一步优化资源配置;认清区域资源的特点,发展区域特色农业;改变传统落后的灌溉方式,大力发展集水型生态农业;严格控制人口数量,全面提高人口素质;加强科技创新,普及可持续发展意识;建立资源可持续利用的宏观调控机制,形成持续稳定的良性生存环境。     

水土保持与草林牧生态配置探讨

通过水土保持工作实践,分析了循化县水土保持与草林牧间生态配置系统相互影响和效益,提出了配置的实施措施。