广东-海南海岸带生态系统服务价值评估

采用Costanza等的分类系统和相关服务的单位价值，根据广东省1987年海岸带和海涂资源综合调查报告和其他相关资料，初步估算出广东—海南海岸带的生态系统服务的总价值为316．97亿美元／a，其中陆地为187．38亿美元／a、海域为129.59亿美元／a。该总价值占全国总价值的407％，养分循环、水分调节、休闲和水分供给等服务的价值突出，分别为全国总价值的6．17、3.98、3．66和3.37％由于自然生态系统的复杂性和不确定性，以及计算参数和方法存在缺陷，因而得到的只是一个偏低的保守值，有待今后改进。     

Profitability of intensification technologies among smallholder maize farmers in the forest-savanna transition zone of Nigeria

Sustaining the productive capacity of the land resource under the existing land-use system and increasing population pressure requires the use of appropriate technologies that will enhance farm productivity and income levels.This paper examines the effect on farm profitability of smallholder maize farmers’ use of intensification technologies in tropical agriculture. The survey was conducted in southwest Nigeria. A multi-stage sampling technique was used to select 300 respondents from two major agroclimatic zones in Osun State. Primary data were collected using a structured questionnaire and complemented with focus group discussions (FGDs), while the State’s Ministry of Agriculture provided secondary data.Pressure on land was found high because farmland was continuously cropped for an average of 10 years with a mean fallow period of 2 years only. Technologies used to intensify agriculture included inorganic fertilizer, organic manure, alley cropping, and tree planting.Results from costs and returns analysis showed that average net returns to inorganic fertilizer use ranked highest in the two zones, while tree planting ranked lowest. There was a significant ecoregional difference on the average net returns/year earned by users of mineral fertilizer. While organic manure use earned higher net returns than alley cropping practice in the rain forest, the reverse was the case for the derived savanna. FGDs revealed that respondents’ preferred to use inorganic fertilizer despite its inadequate supply because, apart from enhancing higher returns and net gains, it also improved output level and provided an opportunity for the continuous use of the scarce land.These results imply that economic returns play a critical role in farmers’ use of intensification technologies and consequently affect their resource management decisions. Policy measures aimed at promoting research on appropriate technologies that are profitable on farmers’ fields will be more effective in enhancing farmers’ use of intensification technologies.     

环境侵害民事诉讼若干问题探讨

随着社会经济发展到一定阶段,人们的物质文化需求与日益脆弱的环境现实必然产生矛盾--即发展与环境的矛盾.而这种矛盾所导致的结果就是环境侵害案件的不断增多,而由于我国长期以来一直是一个以计划经济为主的发展中国家,法制建设不足,只是在近二十五年中立法工作才得以提速、加强.而这当中,对环境保护及环境违法处置方面的立法尤显不足,由此造成目前现实中的环境侵害案件,用传统诉讼制度来解决时,问题和缺陷日益显露.深入研究此类案件的特点,将有利于司法部门正确解决纠纷,切实保护当事人的权利.本文对环境侵害之诉讼要件中的诉讼主体的确定,诉讼请求的根据与范围、证明规则,以及诉讼时效等问题进行了初步探讨.     

关于黄土高原空间范围的讨论

长期以来,黄土高原的空间范围缺乏明确的定论。争论的焦点反映出不同学者对自然地理现象空间分布过渡性的认识和处理的差异。本文从黄土、黄土分布区、黄土高原及其毗邻的黄土分布区、黄土高原、典型黄土地貌区等几个不同层次的概念出发,探讨了划分黄土高原的客观标准,并根据野外考察和航卫片判读确定了黄土高原的空间范围。     

有机污染物在多孔介质中的残留

土壤、地下水中的有机污染物主要以自由态、挥发态、溶解态和残留态等四种形态存在 ,其中残留态的部分是最难以去除的 ,残留量的多少是关系治理费用及治理时间长短的最关键因素。本文以柴油为代表 ,对地下水饱和区中有机物的残留进行了试验模拟 ,与非饱和区的残余饱和度进行了比较 ,揭示了饱和区中有机污染物残余的特点 ,并深入分析了其机理。结果表明 ,砂性介质中 ,地下水饱和区中有机污染物的残余饱和度显著大于非饱和区中的残余饱和度 ,因此可以有效地利用这一特性 ,通过降低地下水位使饱和区中部分残留态污染物转化为自由态 ,提高去除效率 ;与非饱和区中多孔介质粒径越小 ,残留量越大的特性相反 ,饱和区中测得的残余柴油饱和度随介质粒径的增大而增大。不同水位变动速度的试验结果表明 ,水位变动速度对粘性大于水的柴油的残余饱和度影响可以忽略不计。     

Ecological-breaking zone originates and its ecosystems reconstruction in arid area

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Implications of Land Use Changes on Carbon Dynamics and Sequestration—Evaluation from Forestry Datasets, India

Forests and soils are a major sink of carbon, and land use changes can affect the magnitude of above ground and below ground carbon stores and the net flux of carbon between the land and the atmosphere. Studies on methods for examining the future consequences of changes in patterns of land use change and carbon flux gains importance, as they provide different options for CO₂ mitigation strategies. In this study, a simulation approach combining Markov chain processes and carbon pools for forests and soils has been implemented to study the carbon flows over a period of time. Markov chains have been computed by converting the land use change and forestry data of India from 1997 to 1999 into a matrix of conditional probabilities reflecting the changes from one class at time t to another class time t+1. Results from Markov modeling suggested Indian forests as a potential sink for 0.94 Gt carbon, with an increase in dense forest area of about 75.93 Mha and decrease of about 3.4 Mha and 5.0 Mha in open and scrub forests, if similar land use changes that occurred during 1997–1999 would continue. The limiting probabilities suggested 34.27 percent as dense forest, 6.90 as open forest, 0.4 percent mangrove forest, 0.1 percent scrub and 58 percent as non-forest area. Although Indian forests are found to be a potential carbon sink, analysis of results from transition probabilities for different years till 2050 suggests that, the forests will continue to be a source of about 20.59 MtC to the atmosphere. The implications of these results in the context of increasing anthropogenic pressure on open and scrub forests and their contribution to carbon source from land use change and forestry sector are discussed. Some of the mitigation aspects to reduce greenhouse gas emissions from land use change and forestry sector in India are also reviewed in the study.     

地下水污染潜势评估方法及应用

本文阐述了地下水污染潜势评估的重要性，介绍了三种方法，对其中的废物－土址－地点相互作用列表法作了详细介绍，并将ＷＳＳＩＭ法用于四川省什邡县化工开发区地下不污染潜势估。