关于水土保持外资项目财务管理办法的制定

在利用外资开展项目时,为了保证项目内部机构之间的财务运作,需要制定一套适合项目内部机构之间使用的财务管理办法。本文针对外资项目资金管理的独特性,重点阐述一套适合项目内部机构之间使用的财务管理办法应包括的内容,以及制定过程中需要注意的问题,希望制定出一套既符合外资项目管理要求,又能满足国内财务管理需求的办法。     

川西北生态环境恶化综合治理能化害为利

通过川西北12县调查,由于森林严重破坏,与日俱增的工业污染,进一步加剧了长江上游生态环境恶化。建议:1.把恢复长江上游生态平衡提到国家总体战略高度,予以重视,2.提高该地区森林覆盖度,是恢复长江上游生态平衡的基础;3.加速开发水力资源,以电护林,以林涵水,是恢复生态平衡的根本大计;4.加强综合治理和综合利用,化害为利。     

Application of a low-cost database to soil erosion and soil conservation studies in the Awash Basin,Ethiopia

In large-scale land resource planning exercises, Geographical Information Systems (GIS) form a valuable means of storing, retrieving, displaying, and analysing spatially-referenced data, as well as enabling the simulation of the consequences of various alternative development options. However, at this scale only generalized policies for the allocation of finance can be made, and the implementation of those policies will invariably require detailed evaluation at the local level. This suggests that expenditure on the central planning process itself should be limited, with funds reserved for later site studies. The form of GIS adopted centrally should also lend itself to easy use and interpretation by policymakers and planners. These requirements suggest that GIS development using proprietary off-the-shelf database management software may be preferable to high-technology GIS software. This paper outlines the development of such a GIS, based on dBase-III-plus and its internal programming language, in the analysis of problems of soil erosion and soil conservation in the large (110,000 km²) drainage basin of the Awash River in Ethiopia. The methodology employed involves the FAO modification of the Universal Soil Loss Equation, which clearly lacks a secure process basis, but is appropriate for the scale of planning involved and the quality of calibration data available. The GIS is used to map patterns of soil erosion, to identify target areas for conservation on the basis of criteria of sensitivity to land use change, and to assess the costs and benefits of conservation work in those areas. It is suggested that the simple form of GIS involved in this study has much to offer environmental managers in developing countries in the rapid development of plans for soil conservation.     

Development of an agricultural weather policy

Climate is one of the most important factors determining the sustainability of agricultural production systems. More emphasis must be placed on understanding the influence of changing climate conditions on sustainable agricultural systems, given the increasing limitations of the natural resource base. Agrometeorologists can play a leading role in bridging the gaps between the diverse multi-disciplinary fields of science, by reaching out to farmers, extension service personnel, and the agricultural business community. The farming community must cope with issues of climate variability and climate change, and, the challenge for agricultural meteorologists is to develop a coordinated national agricultural weather policy to assist agriculture as it deals with these issues. Agricultural weather policy must be formulated so that proactive long-term preparedness activities are strengthened to ensure agricultural sustainability and to preserve natural resources. Preparedness must be the essential foundation of an agricultural weather policy that builds upon mitigation measures and adaptation strategies to cope with climate variability and climate change as it affects agriculture, forestry, rangelands, and fisheries.     

土地整理效益评价探析

土地整理效益评价是土地整理技术研究的一项基础工作,是科学评价土地整理效果的依据,也是土地整理事业不断发展的动力源泉.该文在分析总结国内外土地整理效益内涵和评价方法的基础上,将土地整理经济效益、社会效益和生态效益进行了界定,对国内外土地整理效益评价内容、评价方法、评价技术手段等进行了评析,以期对今后开展土地整理效益评价研究有所借鉴.     

土地整理效益评价探析

土地整理效益评价是土地整理技术研究的一项基础工作，是科学评价土地整理效果的依据，也是土地整理事业不断发展的动力源泉。该文在分析总结国内外土地整理效益内涵和评价方法的基础上，将土地整理经济效益、社会效益和生态效益进行了界定，对国内外土地整理效益评价内容、评价方法、评价技术手段等进行了评析，以期对今后开展土地整理效益评价研究有所借鉴。     

人工林对土壤地力的影响过程及其调控研究进展

土壤是支撑人工林健康生长的基础资源,是营养物质转化和生物多样性保护的主要场所。目前,我国人工林经营中土壤地力衰退问题突出,是制约我国林业生产可持续经营、增大生态安全屏障脆弱性的重要因素。因此,有必要深入认识和理解人工林对土壤地力的影响过程,同时开发保障人工林健康和初级生产力的关键调控技术。本文从土壤物理化学环境、土壤生物群落特性及功能等方面,系统论述了人工林土壤地力的维持机制,重点探讨了林龄结构、林分密度、树种类型等影响人工林地力的地下生态学过程。未来需要关注环境变化下人工林土壤理化性质与生物学性质的耦合机制。现阶段大面积人工林土壤病原菌积累特征不清,土壤病害影响人工林健康的障碍机理也亟待揭示。因此,今后需进一步量化林木健康、土壤生物以及环境之间的互作关系模型,形成从造林配置、过程经营、症状诊断及土壤地力调控等全方位的人工林健康定向调控体系,保障人工林可持续、多目标经营。     

The nature,causes and consequences of desertification in the drylands of Africa

The dryland environment of Africa poses formidable problems for sustainable development. Among these are unpredictable and severe drought, desiccation or aridification due to persistent drought and dryland degradation or desertification. Because these problems overlap in their effects on the ground, often those who seek sustainable development for these drylands tend to view the problems as one and the same. Yet to facilitate the development of appropriate and effective mitigating measures it is important that the differences and interrelationships be clearly understood. This article starts by outlining the differences and interlinkages between desertification, drought, desiccation and climate change and their causal factors. The central theme is the human causes and consequences of desertification in the drylands of Africa. An attempt has been made to unravel the changing views on the human causes, this is followed by a brief outline of the intervening plans and actions to stem the problem. A significant drawback in combating desertification and drought is the failure of African governments to devolve power to the people who are affected, and to link environmental degradation to economic policy. Consequently, many programmes lack local support or are undermined by conflicting trade and agricultural policies pursued by governments. It is contended that, for sustainable development strategies to work, policies should put the welfare of the people in these drylands at the centre of the development agenda and give them the rights and the power to determine their future. They should empower the people to sustain adaptive strategies towards sustainable livelihoods. Also the threats posed to environment and sustainable development by protectionism and overconsumption in the north and structural adjustment programmes (SAPs), call for the removal of distortions created by the import barriers of developed country, the curbing of overconsumption and a fundamental revision in the structure of SAPs to help alleviate poverty and protect the environment in these African countries. It is in the interest of the global community that the environment in Africa is protected. © 1998 John Wiley & Sons, Ltd.     

基于能值理论的唐山市农业生态系统评价

农业生态系统是人类赖以生存的基本系统。为更好地评价区域农业生态系统的运行状况和变化特点,了解区域资源、环境和经济间的关系,选取唐山农业生态系统为研究对象,基于能值分析理论与方法,通过编制能值评价指标体系,对唐山市农业生态系统能值投入和产出状况、能值自给率、净能值产出率、人均能值用量、环境负载率和可持续发展状况进行定量评价。结果表明:唐山市农业生态系统整体运行较差,农业生态系统为消费型经济系统,可持续性有待提高;以农业用电、农机动力、柴油和化肥为代表的不可更新工业辅助能值投入逐年增加,使得农业生态系统能值产出率和可持续发展指数有一定下降趋势,且增大了对生态环境的压力。研究建议唐山市发展生态农业和现代农业,应着眼于拓展农业多功能性,逐渐改变传统农业生产方式,突出农业生态内涵,进而改变农业生态系统的能值投入和产出结构,促进其可持续发展。     

Soil water and crop production in Botswana

Abstract. This paper draws on the results of a five-year project on the agronomy, crop physiology and soil physics of the cropping of sorghum and subsidiary crops at several sites in Botswana. The low and erratic yields usually obtained stem largely from the low and erratic rainfall, the harsh physical properties of the soils and the unfavourable interactions between these factors. Deep ploughing is essential to allow root penetration and water retrieval from depth in soils of high bulk density; sorghum plant densities must be kept moderately low, at the price of increased surface evaporation, to ensure that plants are big enough to optimize harvest index; and intercropping with cowpeas should be avoided, since it decreases sorghum yield stability with little appreciable compensation. One essential for a more stable, higher-yielding cropping system is the year-round management of the soil as a water storage medium. This will require the alternation of short periods of bare fallow with a sequence of crops with short and long growth cycles.     

黑龙江省畜禽养殖环境承载能力分析及预测

运用系统分析方法及灰色预测模型,对黑龙江省畜禽养殖环境承载能力进行了分析和预测.分析结果表明,目前黑龙江省畜禽养殖环境承载能力较强,但呈现明显的下降趋势.按目前的模式和速度发展,如不对畜禽排泄物进行任何处理,预测至2015年,黑龙江省畜禽养殖环境承载能力下降至警戒值以下;如果将70%的畜禽排泄物转化为能源、饲料、肥料等,预测黑龙江省畜禽养殖环境承载能力下降至警戒值以下的年份为2017年.因此,畜禽排泄物污染问题对于黑龙江省这样一个自然资源丰富的畜牧大省仍是一个必须重视的问题.     

退耕还林背景下寒地山区土地生态安全格局动态变化

为了研究退耕还林工程引起的土地生态安全格局变化,该文应用遥感和GIS技术对牡丹江地区2000-2014年土地利用变化特征进行了分析,并基于DPSIR概念框架构建评价指标体系,从空间上揭示了研究区退耕还林期间土地生态安全水平及格局变化.结果表明,退耕还林工程的实施对研究区土地利用结构产生了极大的影响,林地面积增加1 520.16 km2,草地、耕地面积分别减少878.50、517.14km2,土地利用强度先下降后上升:退耕还林工程在有效控制坡地垦殖、增加林地面积的同时,能够显著提高区域土地生态安全水平,2000-2014年,各坡度等级内安全、较安全、临界安全面积共增加1 088.6 km2;14 a来研究区土地生态安全水平总体呈“先改善后恶化”的趋势,但仍较2000年工程实施前有了较大幅度的提升,西部、东部及南部地区土地生态安全水平显著提高,但中部牡丹江河谷盆地土地生态安全水平提升缓慢,建议新一轮退耕还林工程将此地区作为重点调控整治区域.     

建筑垃圾再生骨料在海绵城市储水结构体中的应用

[目的]研究建筑垃圾骨料对环境的影响,为建筑垃圾再生骨料用于“海绵城市”储水结构体等提供依据。[方法]通过室内大型压缩固结试验,对建筑垃圾再生骨料在不同配比、不同含水率的颗粒破碎、压缩变形及储水率变化进行了研究,并通过浸出毒性试验对建筑垃圾骨料对环境的影响进行了研究。[结果]再生骨料在压缩过程中具有破碎趋势,且废砖骨料破碎程度大于废混凝土骨料;随着废砖骨料比例的增加,颗粒破碎程度越大,压缩变形也愈大;骨料含水率对颗粒破碎影响机制不尽相同,当含水率从3%增加到12%时,颗粒破碎率从121.73%上升至132.64%,而含水率从12%上升至15%时,颗粒破碎率从132.64%下降至127.6%,在“最优含水率”(11.56%)附近取得极大值,且含水率通过影响颗粒破碎来影响再生骨料的压缩变形,颗粒破碎变化趋势与重型击实试验曲线具有一致性。可通过“最优含水率”指导储水结构体含水率的控制,减少颗粒破碎,提高结构体储水能力和承载能力。不同地区的建筑垃圾骨料对环境的影响不同,在应用中应避免已污染建筑垃圾的再利用。[结论]建筑垃圾再生骨料可用于海绵城市储水结构体的建设,但需对建筑垃圾的来源进行区分,确保材料对环境无污染。     

Assessment of seafood processing wastes as alternative sources of Selenium in plant production

Abstract

In some parts of the world, the soil selenium (Se) content is too low to ensure the Se level recommended for human or animal consumption in the crops produced. In order to secure a desired concentration of Se in crops, Se has been applied as mineral fertilizer to agricultural fields. Since only a minor part of the inorganic Se applied is utilized by plants and small increases in Se concentrations in, e.g., drinking water, may be toxic, the method is somewhat controversial. As an alternative to Se-enriched mineral fertilizer, different seafood-processing wastes have been examined as a source for Se in crop production. Both in greenhouse pot experiments and field trials the Se in seafood waste was not plant-available during the first growing season. There was no significant difference between the Se concentration in wheat growing in soil without added Se and in soil receiving Se from seafood waste in amounts ranging from 0.9 to 9 g ha^?1. Neither was any residual effect of Se in seafood waste seen during a second year growth period. Thus, seafood-processing waste cannot be regarded as a potential source of Se in crop production. Possible mobilization of formerly applied Se, as seafood-processing waste or Se enriched mineral fertilizer due to changes in soil redox conditions were examined in a leaching experiment. The mobility of formerly applied Se was generally very low, but the results indicated that under permanently wet soil conditions leaching of Se may occur in plant dormant periods in soils with low organic matter content and high pH.     

The Environmental Consequences of the Conservation Tillage Adoption Decision in Agriculture in the United States

The environmental consequences of conservation tillage practices are an important issue concerning the impact of agricultural production on the environment. While it is generally recognized that water runoff and soil erosion will decline as no tillage and mulch tillage systems are used more extensively on cropland, what will happen to pesticide and fertilizer use remains uncertain. To gain some insight into this, the conservation tillage adoption decision is modelled. Starting with the assumption that this dicision is a two step procedure – the first is the decision whether or not adopt a conservation tillage production system and the second is the decision on the extent to which conservation tillage should be used – appropriate models of the Cragg and Heckman (dominance) type are estimated. Based on farm-level data on corn production in the United States for 1987, the profile of a farm on which conservation tillage was adopted is that cropland had above average slope and experienced above average rainfall, the farm was a cash grain enterprise, and it had an above average expenditure on pesticides and a below average expenditure on fuel and a below average expenditure on custom pesticide applications. Additionally, for a farm adopting a no tillage production practice, an above average expenditure was made on fertilizer.     

基于多时相遥感影像分析的城市土地利用/覆盖变化与热环境演变--以徐州市为例

以1987,1994,2000和2005年共4期的Landsat TM遥感影像为数据源,利用先进的决策树分类法获取徐州市土地利用/覆盖信息,通过单通道算法反演地表亮温获取城市热场分布与热环境变化信息,采用土壤调节植被指数SAVI定量描述研究区植被覆盖变化,并综合采用这些信息对城市热环境演变与城市扩展、植被覆盖变化的关系进行了综合分析.结果表明,利用Landsat TM数据结合决策树分类方法,是获取土地覆盖/利用的有效方法.通过计算地表辐射亮温来研究城市热环境变化是合适的,SAVI等因子与城市热环境显著相关,能够有效地定量描述城市扩展及其生态环境响应.研究结果可服务于城市环境保护与人居环境改善.     

宁南山区生态重建限制性因素分析

通过对宁南山区生态重建中面临的限制性因素,如地理环境的过渡性、复杂性及脆弱性、贫困、落后的文化和制度的分析,指出宁南山区生态重建要突破严酷的地理环境与贫困等因素的限制,应当细化生态区划、选择合适种群以增加生态群落的多样性和稳定性、发展生态文化教育、采取群众参与生态重建的原则,以确保生态重建科学合理地进行。     

Legal aspects of soil conservation and land cadaster works

The analysis of modern Russian legislation in the sphere of environmental protection, management of natural resources, soil conservation, and land cadaster works has been performed. It is shown that a common federal approach to environmental impact assessments and soil quality assessments is virtually absent. Ecological indices are not taken into account in the federal land cadaster. Most of the recently adopted legislative regulations in this sphere have a technocratic character. The recent governmental regulations on land and environmental monitoring have still not been put into practice. To ensure soil conservation policy and protect soils as a component of the environment, a distinction should be made between the notions of soil and land in the legal documents. The basic principles of the proposed law “On Soil Conservation” are outlined. It is argued that a system of soil-ecological criteria should be elaborated for the proper assessment of soil quality. As a soil conservation service is absent in Russia, it is suggested that the Dokuchaev Soil Science Society should organize an association for the protection and rehabilitation of Russian soils.     

长期土壤肥力试验的科学价值

长期土壤肥力试验跨越相当长的时间尺度,可广泛利用于研究众多学科如农学、土壤学、生物学、生态学、气象学和环境科学等有关的科学问题。超过百年历史的长期肥力试验记录着人类活动和环境变迁的丰富信息,是有着巨大科学价值的人类宝贵财富。未来长期肥力试验研究的重要任务之一便是深入开发这一巨大的科学信息库。     

干旱区人工生态系统的持续发展与耗散结构理论

运用耗散结构理论并结合持续发展理论对干旱区生态系统进行了剖析,提出建立和开发人工绿洲生态系统、实施持续发展战略是干旱区生态系统由荒漠向耗散结构生态经济系统发展的必由之路。