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61.
The reestablisment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and β-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.  相似文献   
62.
Pork producers in Western Europe moreand more encounter a variety of societalconcerns about pork and pork production. Sofar, however, producers predominantly focusedon low consumer prices, therewith addressingjust one concern. This resulted in an intensiveand large-scale production system, decreasinglyrelated to the area of farm land, andaccompanied with increasing concerns aboutsafety and healthiness of pork, animal welfare,environmental pollution, and others.An overview was given of possible concernsabout West-European pork production with theconsumers, citizens, and producers, and thoseconcerns are traced back to the pork productionsystem. The various kinds and qualities ofinformation about the pork production system onwhich possible concerns are based have beenworked out extensively in this paper. Knowledgeabout the aspects of pork production that cangive rise to concerns can be used in two ways.First, the communication about those aspectstowards consumers and citizens can be adjustedor extended to give them better possibilitiesto make food choices or to develop their ownopinions about pork production. Second,producers could change the pork productionsystem such that it better satisfies consumersand citizens. Such adaptations are wellpossible, as three pork quality schemes, whichhave been evaluated, illustrate. However, mostof these adaptations can only be carried out atthe cost of the present low consumer prices andwill not occur spontaneously on a large scale.Therefore, accounting for the type andrelevance of the concerns, legislation isnecessary to address societal concerns in abalanced way such that pork production systemsbecome acceptable for the majority of oursociety.  相似文献   
63.
工业生态系统及其建设   总被引:10,自引:0,他引:10  
本文分析了工业生态系统的基本特征及核心内容、阐述了工业生态系统建设的基础,原则及其对策。  相似文献   
64.
塔克拉玛干沙漠腹地沙尘暴特征--以塔中地区为例   总被引:13,自引:2,他引:13  
塔克拉玛干沙漠是中国油气开发的重要区域,沙尘暴是该区域重要的灾害性天气,但以往相关的研究很少。为了了解塔克拉玛干沙漠腹地沙尘暴的发生规律,利用塔中气象站1997-2002年的气象资料,对塔中地区沙尘暴的强度、过程、类型和时间变化等特征进行了分析。研究结果表明:(1)塔中年平均沙尘暴日数为16.83d,较沙漠北缘的轮台和沙漠南缘的民丰、和田为多,体现出沙尘源对沙尘暴发生的影响;(2)沙尘暴发生之前出现明显的风速突然降低和风向转换;(3)同塔里木盆地其它区域一样,塔中沙尘暴也可分为5种类型,其主导类型为冷空气东灌型;(4)沙尘暴时间变化规律明显,且从20世纪90年代至21世纪初,塔中沙尘暴日数与持时明显下降,同全疆的变化趋势一致。  相似文献   
65.
The redevelopment of brownfields has become a central component of government efforts to revitalize many US cities. While the focus of these efforts has concentrated on promoting industrial and commercial redevelopment, some cities have started to also consider converting brownfields into parks and open space as part of a more comprehensive renewal strategy. Based on a survey of 20 case studies, this paper identifies and discusses: (1) the primary issues involved in brownfield greening projects; (2) the benefits of such projects; and (3) the specific planning processes involved. The overall conclusion drawn from the survey is that numerous renewal‐oriented benefits can ensue from greening projects, if there is extensive stakeholder commitment devoted to deal with its financial and development‐oriented challenges.  相似文献   
66.
A programme of large-scale experiments for atmospheric dispersion was carried out by INERIS over a period extending from December 1996 to April 1997. The objectives of the test campaign were to measure anhydrous ammonia concentrations in a range of few meters to 2 km from the release, in order to generate data to be used to improve 2-phase discharge and dispersion modelling.

The discharges were released from a 6-tonne storage tank of pressurised liquid ammonia and through a discharge device with an outlet diameter of 2 in. Fifteen trials were carried out with various release configurations corresponding to industrial situations (impinging jets on the ground and on a wall at various distances, release through a flange without seal…). The quantity of ammonia discharged from the liquid phase varied according to the tests, from 1.4 to 3.5 tons for durations between 7 and 14 min and, therefore, at flow rates between 2 and 4.5 kg/s. Approximately 200 sensors were settled downwind to measure ammonia concentrations and temperature in the plume. These tests showed that for discharges with identical flow rates the distances corresponding to the same concentration vary a lot according to the configurations. These distances tend to be reduced by the presence of obstacles or retention dikes that collected liquid ammonia. In the paper, the main experimental results are presented. In order to enable the comparisons with numerical predictions, more detailed information are given in [Bouet R. (1999). Ammoniac—Essais de dispersion atmosphérique à grande échelle. INERIS rapport, ref INERIS-DRA-RBo-1999-20410 (available at http://www.ineris.fr/recherches/recherches.htm).  相似文献   

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This study aimed at finding effective strategies for high-performance removal of reactive blue 19 (RB19) dye from aqueous solution. Chitosan (CS) films had been prepared by using solvent casting with mild drying for this purpose. The CS films were characterized by X-ray diffraction, field-emission scanning electron microscopy, and Fourier transform infrared (FTIR) spectroscopy. The performance of RB19 removal using CS were evaluated by varying contact time, solution pH, initial dye concentration, and adsorbent dosage. Adsorption isotherms, kinetics, and desorption were investigated by batch experiments. Results showed that CS films exhibited the optimal adsorption performance for RB19 removal and high maximum adsorption capacities of RB19, which were 799 and 822.4 mg g?1 at 20 and 40 °C, respectively. Adsorption kinetic data were well described by the pseudo-second-order kinetic model. FTIR analyses further indicated that interactions between RB19 and the CS film occurred during adsorption. The CS films also exhibited satisfactory desorption of RB19 at about 80 % after 30 min of desorption at pH 11. Our study demonstrated that the CS films can be easily prepared and applied for effective removal of RB19 in treatment of wastewater.  相似文献   
70.
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