Traditional agriculture in transition: examining the impacts of agricultural modernization on smallholder farming in Ghana under the new Green Revolution

Following the renewed effort at achieving a new green revolution for Africa, emphasis has been placed on modernizing smallholder agriculture through the deployment of improved inputs especially mechanized technologies. In Ghana, the government has in the last decade emphasized the provision of subsidized mechanized ploughing services to farmers alongside a rapidly growing private sector tractor service market. While mechanized technology adoption rates have increased rapidly, the deployment of these technologies has been without critical analysis of the impacts on production patterns and local agrarian systems. This paper examines the distributional impacts of agriculture mechanization on cropping patterns and farm sizes of smallholder farmers in northern Ghana using Geographic Information Systems (GIS) techniques, and semi-structured interviews with smallholder farmers (n=60). Specifically, comparative analysis of the field sizes and cropping patterns of participant farmers prior to and after the adoption of mechanized technologies was conducted. In-depth interviews were used to contextualize the experiences of smallholder farmers toward understanding how mechanization may be impacting traditional agriculture. Our findings reveal a mechanization paradox in which farm sizes are expanding, while cropping patterns are shifting away from traditional staple crops (pearl millet and sorghum bicolor) to market-oriented crops (maize, rice and groundnuts). This transition we argue, has adverse implications on the cultural dimension of food security, the organization of social life, and climate change adaptation. We recommend a retooling of the current agricultural policy focus to ensure context sensitivity for a more robust battle against food insecurity.     

Perceptions toward stewardship among residents living near U.S. Department of Energy Nuclear Facilities

Although stewardship has been widely defined and used in environmental management and planning, there is a dearth of studies that describe how the lay public perceives this concept. A national sample of residents in 14 states who live near DOE nuclear facilities were interviewed to delineate public understanding and awareness of the stewardship program of the U.S. Department of Energy (DOE). This study discusses the findings of the survey and discusses how institutional trust influences public participation and resident’s choices of potential stewards. Almost 40% of the respondents could not define stewardship; those who did, believed that ‘responsibility,’ ‘management,’ and ‘accountability’ are key elements of stewardship. In addition, about a third of the respondents identified Federal groups and the DOE as potential stewards. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue     

长江流域水生态环境安全主要问题、形势与对策

为进一步深化长江流域水生态环境保护的系统性、整体性科学认识,围绕长江水生态环境安全的主要问题及形势进行了剖析,提出了进一步加强长江流域水生态环境安全保障的对策建议.研究表明:在水环境质量方面,磷污染成为制约水质改善的主要影响因素,农业源排放量占比高,但工业源入河对水体的影响更直接,水库群运行带来的水沙条件变化对磷污染沿程演变有明显影响;在水生态健康方面,长江水生生物资源衰退、湖库富营养化格局发生改变、湿地生态功能退化问题突出;在水环境风险方面,化工围江、航运污染风险引起广泛关注.当前长江流域面临着源头区水资源战略储备减少、区域经济发展与生态环境保护双重压力仍较大、水环境质量仍存问题隐患、水生态系统退化态势未得到根本遏制等复杂且严峻的形势,未来长江水生态环境安全保障仍有诸多挑战.建议统筹长江全流域“一盘棋”,推进区域绿色协调发展,强化磷污染点面源综合管控,着力提升水生态健康水平,同时加快水环境风险隐患排查整治,强化科技创新有效供给.      

大力开展清洁生产做好节能环保工作

在开展清洁生产过程中，江苏油田真武天然气集中处理站通过节约用水和冷量回收工艺的技术改造，减少了外排水，使水得到循环利用；能量得到很好的利用，增加了产品的产量，给企业增加了经济效益。     

Energy use and transport correlation linking personal and travel related energy uses to the urban structure

This paper considers relationships between sustainability objectives, transport, spatial design of the built environment and rational use of energy. Conventional transport modelling, housing supply and energy assessment tools are drawn together to provide a common platform for appraisal of city-wide energy use by stationary and mobile sources. The paper outlines methodologies developed for the city of Belfast, Northern Ireland. The paper concludes by briefly reviewing the effect in terms of mobile and stationary energy consumption and travel behaviour of implementing sustainable policy measures in current and future years within the study area.     

Comparison of mesophilic and thermophilic anaerobic digestions of thermal hydrolysis pretreated swine manure: Process performance, microbial communities and energy balance

Anaerobic digestion (AD) of swine manure (SM) commonly shows low biogas output and unsatisfactory economic performance. In this study, thermophilic AD (TAD, 50 ± 1 °C) was combined with thermal hydrolysis pretreatment (THP, 170 °C/10 bar), to investigate its potential for maximizing biogas yield, securing successful digestion and microbial diversity, as well as improving energy balance. Four lab-scale continuously stirred tank reactors were operated for 300 days and compared with each other, i.e., reactor 1 (raw SM fed in mesophilic AD: RSM-MAD), reactor 2 (THP-treated SM fed in MAD: TSM-MAD), reactor 3 (RSM-TAD), and reactor 4 (TSM-TAD). The results showed that THP was efficient to increase methane production of SM, TSM-TAD mode led to the highest methane yield (129.8 ± 40.5 mL-CH₄/g-VS/day) among the tests (p < 0.05). Although TAD was more likely to induce free ammonia (> 700 mg/L) or volatile fatty acids (> 6000 mg/L) accumulation compared with MAD in start-up phase, TSM-TAD treatment mode behaved a sustainable digestion process in a long-term operation. For TSM-TAD scenario, higher Shannon–Weaver (3.873) and lower Simpson index (0.061) indicated this mode ensured and enlarged the diversity of bacteria communities. Phylum Bathyarchaeota was dominant (59.3%−90.0%) in archaea community, followed by Euryarchaeota in the four reactors. RSM-MAD treatment mode achieved the highest energy output (4.65 GJ/day), TSM-TAD was less effective (−17.38 GJ/day) due to increased energy demands. Thus improving the energetic efficiency of THP units is recommended for the development of TSM-TAD treatment mode.     

西藏食物保障度分析及对策

食物保障是西藏社会性经济可持续发展重要问题之一。分析表明，西藏食物保障度及目标因食物种类而异。尽管粮食总产及单产均持续增长，但结构性短缺问题难以解决，粮食保障不应过分强调自给率目标；肉类中羊肉自给，但猪肉基本依靠内地；蔬菜保障存在生产不稳定问题，如何提高生产的稳定性是问题的关键。对居民营养摄入量及结构的分析表明，城乡居民食物消费结构及来源结构有较大差异，城镇居民食物消费与内地差异不大，而乡村居民的食物消费呈现极显著的本地化特征；分析还表明，城乡居民生活支出中有一半以上用于食物，表明收入和生活水平还不高，特别要关注低收入居民的食物问题。为此，粮食不应继续作为食物保障的重点，重点应在鲜活食物的保障；建立包括开放食物流通系统和开放食物生产系统在内的开放的食物保障系统；改善交通运输条件、增进食物空间可达性，包括增进食物生产资料空间可达性和改善畜产品外销通径；增强储备意识和能力：保障贫困人口食物供给：广辟食物来源。     

Spatial distribution of ecological security status assessment of West-Liaohe River based on geographic information system

Eco-security assessment is a hot research area in resource and environmental science, which involves data with much spatial, non-linear, and random features. Geographic information system (GIS), as a useful tool to analyze and manage spatial information, has a superior advantage in this field. A case study in the western part of the Liaohe River featuring a method of eco-security spatial differences (ESSD) based on GIS is developed in this paper. The method includes four steps: 1) developing the pressure-state-response (P-S-R) framework with site data; 2) digitizing West-Liaohe River and setting its GRID database of ecosecurity assessment indicators; 3) figuring out the relative membership degree (RMD) of eco-security indicators by using the analytical hierarchy process with the weight of indicator; 4) classifying the security zone and mapping the assessment result of eco-security status in grid by GIS method of assigning and clustering. The visual spatial differences of eco-security based on GIS enables decision makers to know the status of eco-security better in making policies for achieving sustainability. __________ Translated from Environmental Science, 2005, 26(5): 28–33 [译自: 环境科学]     

重庆的能源利用与大气污染

文章分析了大气污染和酸雨对重庆生态环境产生的危害。研究表明，重庆的大气污染主要由燃煤导致，控制大气污染的对策应与能源发展规划相协调，只有降低煤炭使用比例才能使重庆乃至我国的大气污染物排放量做到根本性消减，要把调整能源结构提到能源发展战略的高度     

关于500t／h污水处理场设备运行的探讨

济南炼油厂新建污水处理场采用目前国内石化系统污水处理先进技术，对设备，构筑物等进行实际运行标定。尤其是设备改造，提出作者的见解，同时对污水处理问题进行探讨。