Sustainability: a Dissent

Abstract:  Broadly conceived and considered in its many usages, sustainability has grave defects as a planning goal, particularly when used by conservationists: it confuses means and ends; it is vague about what is being sustained and who or what is doing the sustaining; it is uninspiring; it is little more than Pinchot-era conservation (and thus ignores the many lessons learned since then); it need not be linked to land, to the land's functioning, or to any ecological science; it need not include a moral component; it is consistent with the view of humans as all-powerful manipulators of the planet; and, in general, it is such a malleable term that its popularity provides only a facade of consensus. When sustainability is defined broadly to include the full range of economic and social aspirations, it poses the particular risk that ecological and biodiversity concerns will be cast aside in favor of more pressing human wants. Given these many defects, the conservation movement should discard the term in favor of a more alluring goal, attentive to nature and its ecological functioning. A sound goal would incorporate and distill the considerable ecological and moral wisdom accumulated since Pinchot's day while giving conservationists the rhetorical tools needed to defend the land against competing pressures. In our view, conservation would be well served by an updated variant of "land health," Aldo Leopold's ecologically grounded goal from the 1940s. Land health as an independent understanding should set the essential terms of how we live and enjoy the earth, providing the framework within which we pursue our many social and economic aims.     

提高高职院校学生竞争力的途径

为了应对国际挑战，为了促进高职学生就业及构建和谐社会，高职院校应在专业设置，课程安排，职业教育与培养人文精神并重等几方面着眼来对学生进行全面塑造。     

小城镇的生态环境保护

在城镇化不断发展的进程中，小城镇的生态环境日益恶化。分析了小城镇生态环境存在的问题，提出了应采取的生态环境保护规划与对策。     

编制滇池流域水污染防治"十一五"规划的初步设想

从回顾滇池流域水污染防治“九五”计划和“十五”计划的编制入手,分析了1995、2000、2005年滇池流域的水污染变化趋势,提出了编制“十一五”规划的初步设想。     

抚顺生态城市建设的现状与措施

介绍生态平衡城市的基本条件及抚顺市在建设生态平衡型城市中的基本状况的基础上提出了相关的措施。根据归纳和调查目前抚顺市在经济发展的9项指标中只有2项，环境保护指标15项中只有8项满足生态平衡型城市方面的指标。这说明抚顺市在这方面还存在着很大差距，于是文中进一步提出了相关建议和措施。     

The influence of source and timing of nitrogen fertilizers on yield and nitrogen use efficiency of four sweet potato cultivars

Nitrogen (N) availability is a very important determinant of crop yield. It is also one of the most expensive inputs in crop production. Thus, the efficient management of N by farmers with limited resource is a very important part of successful soil and crop management system. A field study was conducted on a Norfolk sandy loam soil at the George Washington Carver Agricultural Experiment Station, Tuskegee, AL, to evaluate the influence of fertilizer source and timing on the yield of four sweet potato [Ipomoea batatas (L.)] cultivars. Two N sources (urea, CO(NH₂)₂ and ammonium nitrate, NH₄NO₃), four sweet potato cultivars (‘Georgia Jet’, GA-Jet; ‘TU-82-155’, TU-155; ‘TU-1892’; and ‘Rojo Blanco’, Rojo-Bl) and three times (zero, single, and split applications) were used in a factorial designed experiment. Plants were harvested after 80 and 120 days and total and marketable yields determined. Nitrogen recovery efficiency, yield efficiency and physiological efficiency were also determined. Total and marketable yields of early maturing cultivars were significantly higher than of late maturing cultivars (P<0.05). The single application of N resulted in significantly higher yield in storage roots than split application (P<0.05). Physiological efficiency values were highly correlated with total marketable yields. Recovery rates increased with time. Late maturing cultivars tended to have higher N recovery and physiological efficiency than early maturing cultivars. These results suggest that cultivar maturity group should play an important part in N fertilization recommendations for sweet potato.     

人工神经网络模型和公路复垦土地适宜性评价

提出了人工神经网络用于公路临时用地复垦土地适宜性评价，利用该模型对京大高速公路山西段复垦山西段复垦土地进行了适宜性评价，探讨了人工神经网络在土地复垦适宜性评价时的特点和注意问题。     

区域土地可持续利用与环境政策-体化

可持续发展应分阶段、分层次地进行，为增强区域土地可持续利用，相关环境政策的制定遵循可持续发展的原则，提出了区域土地可持续利用的评价流程与环境政策形成的循环模式；介绍了国外区域开发环境影响评价的研究进展及区域环境管理规划的主要内容；分析了这一领域的相关法律问题并提出了建议。     

“城郊型农副业综合经营生态区”探讨

介绍了上海闽行区近年来大中型禽畜场污染治理的典型技术。根据该区的实践及其发展趋势来看,建立“城郊型农副业综合经营生态区“模式势在必行。文章还探讨了“城郊型农副业综合经营生态区”的特征、必要条件以及功能区划方案等。     

南京雨花石

南京出产的雨花石为天赐瑰宝，按照矿物岩石学可分为11类，可从岩石质地、艺术、科学、历史四个方面评价其价值。雨花石作为砾石、卵石主要是由河流作用形成的，而组成雨花石的原岩的成因各异，火山作用是最为重要的成因方式。雨花石可从产品销售以及发展旅游事业等方面加以利用，搞好规划开发利用时要注意保护资源。