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21.
Landsat 7s recent malfunctioning will result in significant gaps in long-term satellite monitoring of Earth, affecting not only the research of the Earth science community but also conservation users of these data. To determine whether or how important Landsat monitoring is for conservation and natural resource management, we reviewed the Landsat programs history with special emphasis on the development of user groups. We also conducted a bibliographic search to determine the extent to which conservation research has been based on Landsat data. Conservation biologists were not an early user group of Landsat data because a) biologists lacked technical capacity – computers and software – to analyze these data; b) Landsats 1980s commercialization rendered images too costly for biologists budgets; and c) the broad-scale disciplines of conservation biology and landscape ecology did not develop until the mid-to-late 1980s. All these conditions had changed by the 1990s and Landsat imagery became an important tool for conservation biology. Satellite monitoring and Landsat continuity are mandated by the Land Remote Sensing Act of 1992. This legislation leaves open commercial options. However, past experiments with commercial operations were neither viable nor economical, and severely reduced the quality of monitoring, archiving and data access for academia and the public. Future satellite monitoring programs are essential for conservation and natural resource management, must provide continuity with Landsat, and should be government operated. 相似文献
22.
Controlled-release fertilizer(CRF):A green fertilizer for controlling non-point contamination in agriculture 总被引:9,自引:0,他引:9
Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas(N2O) and eutrophication of water bodies. How to solve this problem has become a serious challenge, especially for China as its high ecological pressure. Controlled-release fertilizer(CRF) has been developed to minimize the contamination while keeping high yield and has become a green fertilizer for agriculture. Several CRFs made with special coating technology were used for testing the fertilizer effects in yield and environment through pot experiment and field trial. The result indicated that the CRFs had higher N use efficiency, thus reducing N loss through leaching and volatilization while keeping higher yields. Comparing with imported standard CRFs,the test on CRFs showed similar fertilizer effect but with much lower cost. CRFs application is becoming a new approach for minimizing non-point contamination in agriculture. 相似文献
23.
植物遗传资源保护与利用的市场化机制和国际制度 总被引:9,自引:0,他引:9
随着植物物种资源的不断减少和因生物技术迅猛发展对植物遗传资源需求的不断增加 ,植物遗传资源正逐步由公共物品转变为稀缺物品。坚持《生物多样性公约》所确立的遗传资源效益公平分享原则 ,完善现有国际多边体系 ,促进以“遗传编码功能”价值概念和遗传资源保护效应“内部化”与“补偿”方案为基础的植物遗传资源市场化保护与利用机制的形成 ,建立“植物遗传资源交易所”和“生物多样性合作社” ,将有助于提高世界各国尤其是发展中国家保护植物遗传资源的积极性 ,实现全球植物遗传资源的可持续利用 相似文献
24.
以上海市为例,介绍了地面沉降的危害以及现有的防治对策,同时提出了污水经处理后回用于防治地面沉降的新思想,主要包括两种方法:①将处理后的污水回灌地下补给地下水;②用处理后的污水回用代替部分自来水,减少地下水的开采量,以控制地面沉降。 相似文献
25.
26.
克拉玛依市水,土资源承载力与城市发展对策研究 总被引:2,自引:0,他引:2
在城市可持续发展的进程中,克拉玛依已具备了许多有利条件,但同时也存在一些限制性2。文章重点研究了克拉玛依水、土地资源的承载力与城市发展的关系,从水资源供需平衡,水资源承载力与城市发展规模控制、土地资源人口承载力、工业用地规模、居住用地规模、绿化用地规模和环境管理等方面提出了对策。 相似文献
27.
The effects of land use and its patterns on soil properties in a small catchment of the Loess Plateau 总被引:3,自引:0,他引:3
Due to relatively strong human activities in the hilly area of Loess Plateau,the natural vegetation has been destroyed,and landscape pattern based on agricultural land matrix was land use mosaic composing of shrub land,grassland,woolland and orchard.This pattern has an important effect on soil moisture and soil nutrients.The Danangou catchment,a typical small catchment,was selected to study the effects of land use and its patterns on soil moisture and nutrients in this paper.The results are as follows:The comparisons of soil moisture among seven land uses for wet year and dry year were performed:(1)the average of soil moisture content for whole catchment was 12.11% in wet year,while it was 9.37% in dry year;(2)soil moisture among seven land uses was significantly different in dry year,but not in wet year;(3) form wet year to dry year,the profile type of soil moisture changed from decreasing type to fluctuation-type and from fluctuant type to increasing type;(4)the increasing trend in soil moisture from the top to foot of hillslope occurred in simple land use along slope,while complicated distribution of soil moisture was observed in multiple land uses along slope.The relationships between soil nutrients and land uses and landscape positions were analysed:(1)five nutrient contents of soil organic matter(SOM),total N(TN),available N(AN),total P(TP) and available P(AP) in hilly area were lower than that in other areas.SOM content was less than 1%,TN content less than 0.07%,and TP fallow land and cropland,and higher level in soil fertility was found in crop-fruit intercropping land among croplands;(3)soil nutrient distribution and responses to landscape positions were variable depending on slope and the location of land use types. 相似文献
28.
垃圾转运站污水回用处理采用了膜 -生物反应器处理工艺 ,它具有高效、稳定、工艺流程简单、设备占地面积小和投资少等优点 ,且处理后出水可用于自身站内所需 ,即冲车、喷洒道路、冲厕、绿化、冲刷车间地面等多种用途 ,实现了污水处理后再利用的目的。 相似文献
29.
Toxic metals in sewage sludge-amended soils: has promotion of beneficial use discounted the risks? 总被引:1,自引:0,他引:1
M.B. McBride 《Advances in Environmental Research》2003,8(1):5-19
Land application of contaminated waste products has been defended as beneficial use by some scientists and regulators, based on the premise that the behavior of any toxins accumulated in soils from this practice is reasonably well understood and will not have detrimental agronomic or environmental impacts into the foreseeable future. In this review, I use the case of toxic metals in sewage sludges applied to agricultural land to illustrate that metal behavior in soils and plant uptake is difficult to generalize because it is strongly dependent on the nature of the metal, sludge, soil properties and crop. Nevertheless, permitted agricultural loadings of toxic metals from sewage sludges are typically regulated using the sole criterion of total metal loading or concentrations in soils. Several critical generalizing assumptions about the behavior of sludge-borne metals in soil-crop systems, built into the US EPA risk assessment for metals, have tended to underestimate risks and are shown not to be well justified by published research. It is argued that, in the absence of a basic understanding of metal behavior in each specific situation, a more precautionary approach to toxic metal additions to soils is warranted. 相似文献
30.