最大日负荷总量(TMDL)技术在农业面源污染控制与管理中的应用与发展趋势

介绍了美国最大日负荷总量(total maximum daily load, TMDL)计划的基本内容、基本原理和实施步骤,综述了TMDL计划在国内外实施中常用的流域模型,如SWAT、HSPF和AnnAGNPS模型的研究进展,以及TMDL计划中使用的最佳管理措施(BMPs)及TMDL不确定性分析方面的研究现状.最后,提出了TMDL技术的发展方向,结合我国环境保护和总量控制技术体系现状,展望了TMDL技术在我国农业面源污染控制与管理中的应用前景.     

流域非点源污染控制管理措施的成本效益评价与优选

最佳管理措施是针对非点源污染的控制方案,相关措施的效果评价和经济效益分析,是进行政策手段设计和有效性评价的主要依据.针对北京市密云水库上游太师屯镇的农业非点源污染特征,设计了多种不同最佳管理措施(BMPs).在对非点源污染控制措施控制效果的经济价值估算基础上,综合考察各项措施的费用-效益关系,对所选择措施的投入一产出中的各种经济因素进行研究,通过计算出的不同控制措施的费用效益比、内部收益率、投资回收期、经济净现值等经济指标,对各种控制措施进行对比分析,从工程经济的角度分析、评价各种控制措施的合理性,使污染控制方案既满足流域改善环境的目的,又具有经济上的可行性.研究结果表明:污染控制措施在经济上都是合理和接受的.经济优劣排序为:15°～25°坡耕地变果园>河岸植被缓冲带>0°～15°坡耕地保护性耕作>户用沼气池>25°以上荒草坡还林>0°～15°坡耕地等高植物篱;耕地变为果园和河岸植被缓冲带两项措施,非常适合于该地区,前者经济效益显著,后者环境效益显著,值得大力推广.     

耕地土壤碳固存的措施与潜力

土壤CO2排放与土壤退化、土壤有机质(SOC)含量减少和土壤质量下降密切相关。耕地具有较大的碳固存潜力。通过采用最佳管理措施(BMPs)和进行土壤修复来提高土壤质量，能增加SOC含量和提高土壤生产力，并能部分起到减缓温室效应的作用。文章从土壤固碳的机制入手，系统总结了在耕作土壤碳固存方面的研究。从土壤侵蚀控制、退化土壤修复、保护性耕作、残落物管理，改善农作物制度等方面，论述了耕地的固碳潜力，并提出了一系列实现碳固存的措施。最后估算出耕地土壤总的固碳潜力为0．73～0．87Pg/a。研究表明,在替代性能源开发之前，耕地碳固存是一项切实可行的措施。     

提高农业更可持续性:趋势和挑战

第八次国际高级研讨会确定了许多支持全球可持续消费与生产的手段.比本文更全面深入的一份文件作为背景文件提交给了题为"可持续农业:让几十亿人吃饱"的分组会议.随后,分组会议成员的稿件和讨论期间的意见都被收编在一起.文件突出了制定和采用更佳管理方法(BMPs)的优点.棉花的例子说明了采用提高物流可持续性的BMPs的潜力.     

提高农业更可持续性：趋势和挑战

第八次国际高级研讨会确定了许多支持全球可持续消费与生产的手段．比本文更全面深入的一份文件作为背景文件提交给了题为“可持续农业：让几十亿人吃饱”的分组会议．随后。分组会议成员的稿件和讨论期间的意见都被收编在一起．文件突出了制定和采用更佳管理方法（BMPs）的优点．棉花的例子说明了采用提高物流可持续性的BMPs的潜力．     

生境评价程序在规划环境影响评价中的应用——以大东港区规划为例

对美国广泛应用的生境评价程序(HEP)在程序和方法上进行了改进和简化,在分析现有各生境单元指示物种密度的基础上,根据项目拟占用生境情况,预测拟议项目对指示物种的影响.以丹东港大东港区规划为例,应用改进的HEP,定量分析了大东港区规划对指示物种(涉禽和水鸟)觅食生境的影响,并制定了生境弥补计划和生态减缓措施.     

中国农业领域温室气体主要减排措施研究分析

气候变暖已成不争事实,主要是由于人为温室气体(GHG)排放增加所致,为减缓气候变暖趋势,各领域迫切需要采取减排措施;农业是一个重要的GHG排放源,农业领域采取减排措施对于减少我国GHG排放、保护农村生态环境有重要意义。文章在大量阅读前人研究结果的基础上,总结我国农业领域主要的减排管理措施,主要从农业活动、农村生活和生物质能源利用三方面进行阐述,并简要分析各措施的减排效果和存在问题。分析发现,农业活动的水肥管理是农田温室气体减排的研究热点,但由于地域和管理流程上的差异,对措施的减排效果尚存在争议;农村生活中存在巨大的减排潜力,采取恰当的减排措施不但可以减少GHG排放,还可以改善农村生态状况和环境卫生条件;农村生物质能源有很大发展潜力,合理开发利用,可以有效替代化石能源消耗,缓解能源危机,减少GHG排放,保护生态环境。总之,在农业领域采取积极的减排措施,有助于国家效应对气候变化,降低农业源污染和GHG排放,减轻环境压力,转换农业发展模式,加速农业现代化,促进农业生产的可持续发展和社会主义新农村建设。     

水分管理和秸秆还田对稻麦轮作系统温室气体排放的综合效应

水分管理和秸秆还田是调节温室气体排放、提高作物产量的有效措施,在农业生产中受到广泛关注。为明确水稻季水分管理和秸秆还田对稻麦轮作系统全球增温潜势(GWP)和作物产量的影响,开展了为期两年的田间试验,在传统灌溉(TI)和控制灌溉(CI)两种模式的基础上,设置麦秸还田(WS)、生物炭还田(BC)、不还田(NS)3种秸秆处理方式,对稻麦轮作系统进行CH_4和N_2O的排放监测以及作物产量的评估,以筛选出最佳的水分管理和秸秆还田组合方式,为农业的可持续发展提供科学依据。结果显示,与NS处理相比,WS、BC处理年均CH_4排放分别增加106.02%、36.77%,年均N_2O排放分别降低27.25%、16.21%,稻麦年平均产量分别增加6.49%、5.90%,年均单位产量GWP(GWPyield-scaled)分别增加40.53%、8.07%。在整个轮作周期,CI系统的CH_4排放较TI降低79.63%,N_2O排放增加27.03%,稻麦年平均产量增加0.42%,单位产量GWP降低60.32%。各处理中,以控制灌溉加生物炭还田(CIB)的年均单位产量GWP最低,比传统灌溉不还田(TINS)、传统灌溉麦秸还田(TIS)、传统灌溉生物炭还田(TIB)、控制灌溉不还田(CINS)、控制灌溉麦秸还田(CIS)分别降低53.81%、70.49%、59.77%、4.46%、11.92%。水分管理和秸秆处理方式对全球增温潜势表现出强烈的交互作用,但对作物产量无明显交互作用。可见,控制灌溉加生物炭还田(CIB)是降低稻麦轮作系统温室气体排放提高作物产量的有效管理措施。     

亚热带东部丘陵山地农业发展的灰色局势决策

本文在亚热带东部主要丘陵山地(神农架、大别山、雪峰山和云开大山等)自然资源农业评价的基础上,以经济效益为指际对农业发展实施灰色局势决策。结论:1.发展粮食作物和经济作物必须摆在各地区五业之首;2.农林经济效益在神农架南坡最佳,畜牧业和工副业在云开大山最有前途。     

四川开县农业生态环境质量评价与对策(一)

本文基于农业生态条件和农田生态系统功能的综合表现,评价了研究区农业生态质量,分析研究了农业生态环境存在的问题,提出了保护对策。计价中,生态条件要素选取了土壤环境(包括土壤综合肥力、土壤污染状况的有关参数),大气环境(包括大气资源和大气质量的有关参数),水环境(包括水资源量和水质的有关参数)。生态系统功能指标选取了农田生产力。经过实地调查,取得了有关参数资料。在单项因素分级指数评价的基础上,采取评分等权迭加法进行综合评价,对开县地区农业生态质量作了定量表征,并对县内不同农业区的生态质量进行排序。     

System engineering for water pollution control at the watershed level in China

The present water pollution situation at watershed level in China has been systematically analyzed. The causes of water pollution are attributed to the extensive economic developmental pattern, poor wastewater treatment, and a lack of nonpoint pollution control. The problems of water pollution control at watershed level include a lack of thought and approach, developmental delay in the environmental standard system, an inadequate monitoring ability, and an inefficient implementation of laws and regulations. From 2006 to 2020, water pollution control and governance will be a national key specific project of science and technology in China. The strategies of this project include establishing a water pollution control system at watershed level, orienting a healthy aquatic ecosystem, conducting risk management, and using comprehensive methods. The goal is to establish and complete a technological system of pollution control and management in three five-year phases. The main tasks are to develop common technologies, management systems, and mechanisms for lake eutrophication control, river pollution control, urban water environmental pollution control, potable water safety, and water environmental management. The bottlenecks of water pollution control and management in China could be systematically removed, and the demonstration of the system engineering approach will be conducted at selected key watersheds.     

Water environmental planning and management at the watershed scale: A case study of Lake Qilu, China

Water environmental planning and management has become essential for guiding the water pollution control activities. Past water pollution control activities have been site specific, with little thought on water quality standard reaching at the watershed scale. Based on the watershed approach, a seven-step methodological framework for water environmental planning and management was developed. The framework was applied to water environmental planning and management of the Lake Qilu watershed in Yunnan Province, China. Results show that the reduction amount of total nitrogen (TN) under the plan is 1,205 tons per year so that the target of environmental capacity can be reached in 2020. Compared with traditional methods, the framework has its prevalence and could be generalized to analogous watersheds.     

A Biophysical Toolbox for assessment and management of land and water resources in rural catchments in Northern Thailand

With rapid intensification of agricultural catchments in Northern Thailand a suite of environmental issues has surfaced. The Integrated Water Resources Assessment and Management (IWRAM) project was instigated in response to these issues. The project developed a Decision Support System (DSS) for the exploration of biophysical and socio-economic impacts of water resource use options. The IWRAM-DSS is comprised of a ‘Biophysical Toolbox’ that can be implemented alone and an ‘Integrated Toolbox’ that links socio-economic models with the Biophysical Toolbox to explore economic trade-offs and impacts of various scenarios. The Biophysical Toolbox is comprised of three modules—the CATCHCROP crop model, a hydrologic module based upon the IHACRES rainfall-runoff model, and a Universal Soil Loss Equation (USLE) approach modified to suit conditions in Northern Thailand. This paper describes the Biophysical Toolbox and runs forest conversion, land management, and climate scenarios to demonstrate the potential of this tool in exploring the environmental effects of land and water management options.     

The application of artificial neural networks to flow and phosphorus dynamics in small streams on the Boreal Plain,with emphasis on the role of wetlands

Historically, management strategies in Canada's boreal forest have focused on forest polygons and terrestrial biodiversity to address ecological considerations in forest management. The Forest Watershed and Riparian Disturbance (FORWARD) project examines the problem from a watershed perspective rather than a forest polygon viewpoint. The main objective of this study was to devise an artificial neural network (ANN) modeling tool that can predict flow and total phosphorus (TP) concentration for ungauged watersheds (where daily flow is not monitored). This dictates that all inputs should be easily accessed via a public domain database, like the Environment Canada weather database, without the need to install flow gauges in each modeled watershed. Daily flow and TP concentration for two of the project watersheds were modeled using ANNs. The two watersheds (1A Creek, 5.1 km² and Willow Creek, 15.6 km²) were chosen to reflect variations in wetland area and composition in the study area. Flow was modeled with a feed-forward multilayer perceptron ANN trained with the error back-propagation algorithm. Simulated values for flow were then used, as inputs, to model TP concentration using the same neural networks algorithm. One hidden layer with three slabs; each operating with a different activation function was utilized to simulate the conceptual differences between base flow, snowmelt, and storm events. Time domain analysis was conducted to identify possible model time-lagged inputs reflecting the time dependency of the modeled variables. Spectral analysis was used to address data hystereses. Our results highlight the capabilities of ANN in modeling complex ecosystems and highly correlated variables. Results also indicated that more research towards the phosphorus dynamics in wetlands is required to better represent the impact of wetland area and composition on the water-phase phosphorus in ANN modeling.     

A model examining hierarchical wetland networks for watershed stormwater management

There is increasing awareness that solutions to degraded quality and excessive quantity of stormwater and resulting impacts on downstream water bodies may require a watershed approach to management rather that the incremental approach that is now common. Examination of low-relief watersheds characteristic of the southeastern coastal plain reveals common hierarchical patterns of surface water convergence that may be emulated in developed watersheds to enhance the efficacy of peak-flow attenuation and pollutant removal. A dynamic systems model was developed to compare stormwater management using a hierarchical network of treatment wetlands with the standard incremental approach wherein treatment systems are designed considering only site-level effluent criteria. The model simulates watershed hydrology, suspended sediment transport and phosphorus removal and transformation. Results indicate that watershed planning of stormwater collection and treatment systems using hierarchical networks can greatly enhance overall effectiveness (annual retention improvements of 31% for flow, 36% for sediment and 27% for phosphorus) with respect to an equal area of uniformly sized wetlands. Further, network proportions can be adjusted to specific runoff characteristics. Distinct roles were observed for each wetland size class: small headwater wetlands effectively removed sediment, medium-sized mid-reach wetlands retained phosphorus, while large wetlands primarily stored and attenuated long-period hydrologic flows.     

Anwendungen von Pflanzenschutzmitteln in der Landwirtschaft

A political dispute has broken out over a research project by the Federal Environmental Agency (UBA) concerning the use of plant protection agents in agriculture. Under Article 15 para. 1 No. 3 d and e of the Plant Protection Act, plant protection agents can only be authorised if their proper and appropriate use, or the consequences of such use, have no negative impacts on human or animal health or on other biological communities, especially water bodies. In specific cases the Federal Environmental Agency as the approving authority fulfils the legislative requirements with a conditional authorisation. Thus, for example, specified minimum distances to the water body must be observed according to the toxicity and exposure of the plant protection agent. The many continuing negative impacts on water bodies from the use of plant protection agents raise questions as to whether certain plant protection agents ought not to have been authorised, and whether environmental requirements were strict enough in the past or whether farmers did not comply with them to a sufficient degree. The research project described here will clarify and document possible improper practices and practical problems. Investigations will be undertaken without prior notice, as only this will enable the actual practices to be recorded. Data will be anonymous, since the project does ’not aim to ‘convict’ individual farmers. The task of the project is to collect representative data for the whole of Germany. Initial interim results will be available in 2006. This report will then be continued in a ‘Part 2’.     

Farmer's perception and response towards land policy and eco-environment based on participatory rural appraisal: A case study in the Loess hilly area,China

Based on a survey of 107 farm households by means of participatory rural appraisal, this paper presents a region-level analysis of farmer's perception and response towards land policies and eco-environment in the Loess hilly area, China. The surveyed farmers are divided into two groups, farmers on non-irrigated farmland and farmers on irrigated farmland. The results indicate that most farmers mainly depend on cropland, especially the farmers on non-irrigated farmland. Farmers believe that stability and persistence of land policies are important, and most hold a positive attitude towards the Grain-for-Green Programme. The farmers on irrigated farmland have a more favourable attitude to environmental conservation than the farmers of non-irrigated farmland. Nearly 80% of interviewees consider that the local eco-environment has improved in the last ten years. About 45% never consider the environmental impact of their agriculture practices. About 55% think drought is the most important reason for eco-environment deterioration, overgrazing and serious soil erosion. Soil and water conservation is not conscious and voluntary behaviour for farmers, it is only a measure to guarantee their basic agricultural production and to improve their living conditions. Results indicate that farmers on nonirrigated land find engineering approaches more beneficial to agronomic methods. However, the farmers on irrigated farmland pay more attention to improving farmland quality.     

What motivates farmers to participate in sustainable agriculture? Evidence and policy implications

Sustained growth in agricultural productivity has become an ideal model and a political goal of agricultural development in China. Local participation is essential for the implementation of sustainable agriculture strategy. We conducted a case study in Hailun County, an important grain production base in China, to find ways to motivate farmers to participate in sustainable agriculture. We obtained data from semi-structured interviews of 98 households using participatory rural appraisal methods. Logistic regression models were used to explore factors that underlie farmers' attitudes towards agricultural production and their environmental awareness. Results indicated that low agricultural economic efficiency could result in less enthusiasm for agriculture among local farmers. This is a potential risk for China's food security and sustainable agricultural development. The backward development of the rural economy limited improvement of farmers' environmental awareness. Moreover, poor rural labour quality implied a lack of local participation in sustainable agriculture. Suggestions for sustainable agricultural development include establishment of a reasonable market and agricultural subsidy mechanisms, basic and vocational education for young adults, effective agricultural instruction and environmental education agencies and two-way communication mechanisms.