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1.
可持续发展战略对环境保护参与国民经济决策提出新的要求.市场经济体制产生“市场失灵”,应加强宏观调控机制,保证经济与环境协调发展.探讨了社会主义市场经济条件下环境与发展宏观调控机制的思路与设想.  相似文献   
2.
Nitrate is prone to leaching in the sandy soils of the West African moist savannas. Better management of nitrogen (N) resources and maize cultivars with enhanced genetic capacity to capture and utilize soil and fertilizer N are strategies that could improve N-use efficiency. In two field experiments conducted at Zaria, northern Nigeria, five maize (Zea mays L.) cultivars planted early in the season were assessed under various N levels for differences in N uptake, soil N dynamics, and related N losses. Cultivar TZB-SR accumulated more N in the aboveground plant parts in both years than the other cultivars. All, except the semi-prolific late (SPL) variety, met about 50–60% of their N demand by the time of silking (64–69 DAP). In both years, SPL had the greatest capacity to take up N during the grain filling period, and it had the highest grain-N concentration and the least apparent N loss through leaching in the second year. There were no significant differences in soil N dynamics among cultivars in both years. At harvest, the residual N in the upper 90 cm of the profile under all the cultivars ranged from 56 to 72 kg ha−1 in the first year and from 73 to 83 kg ha−1 in the second year. Apparent N loss from 0 to 90 cm soil profile through leaching ranged from 35 to 122 kg ha−1 in both years. N application significantly increased N uptake by more than 30% at all sampling dates in the second year of the experiment, but had no effect on apparent N loss. Results indicate that the use of maize cultivars with high N uptake capacity during the grain filling period when maximum leaching losses occur could enhance N recovery and may be effective in reducing leaching losses of mineral N in the moist savanna soils.  相似文献   
3.
本试验以HAc作为厌氧释磷的碳源有机物,以SBR系统外循环污泥作为研究对象,探索外循环活性污泥的厌氧释磷能力和获取高浓度富磷污水的途径,试验表明:厌氧过程中聚磷菌吸收HAc和释放PO4^3 的分子比为1:1。即吸收2.06mgHAc-COD将诱导1mgP释放,单位时段比污泥的平均释磷速率Vp=6.54.t^0.76,理想的厌氧时间为60-180min,减少循环污泥释磷系统的反应容积可以提高富磷污水磷酸盐的浓度。  相似文献   
4.
上海地区高空气流长距离输送轨迹及其与酸雨的关系   总被引:2,自引:0,他引:2  
分析了影响上海地区的高空气流输送轨迹。不同月份影响上海的高空气流来向不一。轨迹输送路径与天气系统的变化密切有关,且与上海地区出现的酸雨有关。研究表明,上海地区的酸雨,除与局地污染有关外,还与远处输送的外来污染有关。这些外来污染影响,主要来自上海西南向的北部湾和两广等地。也有部分来自东北——东方向的南朝鲜和日本西部地区。  相似文献   
5.
We report herein a de novo unbalanced chromosome translocation in a fetus resulting from in vitro fertilization technology. Prenatal diagnostic analysis of an amniotic fluid revealed a 46,XX,4p+ karyotype. The origin of the extra material on the short arm of chromosome 4 could not be identified by a variety of banding techniques. However, examination of fetal parts did reveal some dysmorphic features.  相似文献   
6.
IntroductionFertilizationisessentialforagriculturalproduction ,butunreasonablyapplyingfertilizerscouldresultinseriesofproblemssuchascropqualitydecline,fertilizeruseefficiencydecrease,residualfertilizerspollution groundwaterandriversandnitrogencontented …  相似文献   
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8.
山西矿区矸石山复垦种植施肥策略   总被引:8,自引:1,他引:8  
围绕煤矸石缺乏有机活性物质及有效养分的问题,在矸石山复垦种植时,对施肥作了试验研究。结果表明,煤矸石风化物由于吸附性能低,保肥性差,所以施用化肥时一次用量不宜过大。并从降低复垦的投资与难度以及尽快建立一个可自我维持生长的植被出发,提出了矸石山复垦种植时化肥与污泥配合施用的施肥策略,并对污泥的施用效果做了研究。  相似文献   
9.
新修农田土壤培肥技术试验研究   总被引:1,自引:0,他引:1  
黄土丘陵区土地资源主要以坡地形式存在,近年来声势浩大的坡改梯工程使一部分山坡地变为层层梯田,水土保持率明显提高,而如何进行新生土层的土壤培肥,又是该工程的重要课题。作者对当地近几年土壤培肥技术试验进行了研究。以期提高土地资源的利用率。  相似文献   
10.
This review of the literature on environmental auditing and the potential role of accountants distinguishes between compliance audits and audits of the environmental management system. After an extensive introduction to the concept, this review focuses on the similarities and differences between an environmental audit and a financial statement audit. The general approach to both types of audits is similar, except that environmental audits are largely unregulated. Both audits place an emphasis on the evaluation of control systems, which is an argument in favor of external auditors playing a role in environmental audits. Another argument for including external accountants is their code of ethics. However, these professionals seem to be reluctant to enter the field of environmental auditing. It is argued that this reluctance is because of a lack of generally accepted principles for conducting environmental audits. If external accountants are engaged in environmental auditing, they should be part of multidisciplinary teams that also include scientists and engineers to avoid a too strong focus on procedures. Rather than treating these audits as totally different, it is proposed that there be a move towards integrated, or even universal, audits.  相似文献   
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