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281.
Chunyan Liu Kai Wang Shixie Meng Xunhua Zheng Zaixing Zhou Shenghui Han Deli Chen Zhiping Yang 《Agriculture, ecosystems & environment》2011,140(1-2):226-233
One-year winter wheat–summer maize rotation is the most popular double cropping system in north-central China, and this highly productive system is an important source of nitrous oxide (N2O) and nitric oxide (NO) emissions due to the high fertilizer N and irrigation water inputs. To sustain the high crop production and mitigate the detrimental impacts of N2O and NO emissions, improved management practices are extensively applied. The aim of this study is therefore to evaluate the effects of an improved management practice of irrigation, fertilization and crop straw on grain yield and N2O and NO emissions for a wheat–maize rotation field in northern China. Using automated and manual chamber measuring systems, we monitored N2O and NO fluxes for the conventional (CT, 2007–2008), improved (IT, 2007–2008), straw-amended (WS, 2008–2009), straw-not-amended (NS, 2008–2009), and no N-fertilizer treatments (WS–NN, 2008–2009), respectively, for one rotation-year. The grain yields were determined for CT and IT for three rotation-years (2005–2008) and for WS, NS and WS–NN for one rotation-year (2008–2009). The improved management of irrigation and fertilization reduced the annual N fertilization rate and irrigation amount by 17% and 30%, respectively; increased the maize yield by 7–14%; and significantly decreased the N2O and NO emissions by 7% (p < 0.05) and 29% (p < 0.01), respectively. The incorporation of wheat straw increased the cumulative N2O and NO emissions in the following maize season by 58% (p < 0.01) and 13%, respectively, whereas the effects of maize straw application were not remarkable. The N2O and NO emission factors of applied N were 2.32 ± 2.32% and 0.42 ± 1.69% for wheat straw and 0.67 ± 0.23% and 0.54 ± 0.15% for chemical N-fertilizers, respectively. Compared to conventional management practices using high application rates of irrigation water and chemical N-fertilizer as well as the field burning of crop straw, the improved management strategy presented here has obvious environmentally positive effects on grain yield and mitigation of N2O and NO emissions. 相似文献
282.
基于STIRPAT模型的能源消费碳足迹变化及影响因素——以江苏省苏锡常地区为例 总被引:8,自引:0,他引:8
定量研究经济社会发展对地区能源消费碳足迹的影响对区域实现低碳发展具有重要意义。论文计算了江苏省苏锡常地区1991-2008年能源消费碳足迹,采用岭回归函数对STIRPAT模型进行了拟合,采用脱钩指数分析了经济发展与能源消费碳足迹之间的关系。结果表明:①1991-2008年能源消费碳足迹平均增长速度为15.30%,能源消费碳足迹分配率以煤炭为主,石油所占比例呈波动下降趋势,天然气所占比例上升较快,能源消费碳足迹产值总体呈波动下降趋势;②经济增长是能源消费碳足迹的主要影响因素,两者关系模型拟合未出现环境库兹涅茨曲线;③经济增长与能源消费碳足迹之间处于相对脱钩与复钩的波动状态,从另一侧面验证了目前两者之间不存在库兹涅茨曲线假说的结论。 相似文献
283.
284.
研究了A/O-MBR工艺低温(水温在5~12℃)启动效能,结果表明,低温下A/O-MBR工艺启动迅速,活性污泥的培养驯化时间较短。启动过程中根据出水水质情况,逐渐提高负荷,运行34 d,系统对COD的去除率能达到90%以上,系统对氨氮的去除率能达到96%以上,至稳定运行后氨氮的负荷平均可达到0.419kg/(m3.d),反硝化效果系统去除率基本能稳定在60%左右。 相似文献
285.
试验考察了东阿县污水处理厂一期A2/O工艺厌氧池去除有机污染物效能,当进水ρ(COD)为548.3 mg/L时,厌氧池平均去除率达78.7%。同时探讨了几种常见数学模型模拟厌氧池去除有机物规律情况,根据实际工程监测数据确定有机底物降解动力学常数,得出Grau模型、Stover-kincannon模型和改进的Monod模型较适合模拟厌氧池去除有机物的规律,并对模型进行了检验。 相似文献
286.
Visible light responsive N-F-codoped TiO2 photocatalysts exhibit a higher catalytic activity than N-doped TiO2 for the degradation of 4-chlorophenol due to the synergistic effect of nonmetal elements. 相似文献
287.
Preliminary report on methane emissions from the Three Gorges Reservoir in the summer drainage period 总被引:3,自引:0,他引:3
Fei Lu Le Yang Xiaoke Wang Xiaonan Duan Yujing Mu Wenzhi Song Feixiang Zheng Junfeng Niu Lei Tong Hua Zheng Yongjuan Zhou Jiangxiao Qiu Zhiyun Ouyang 《环境科学学报(英文版)》2011,23(12):2029-2033
Considerable variations may exist in CH4 emissions from the Three Gorges Reservoir. 相似文献
288.
A new type of sponge iron sphere (NSIS) with 1-5 mm diameter, made of concentrated iron powder and possessed high activity and intension, was prepared by mini-pellet sintering integrated with H2 direct reduction. Static state experiment has been carried on to investigate the Cd2+ removal efficiency from wastewater by the NSIS and to explore the Cd2+ removal reaction kinetics. It was suggested that initial pH value and Cd2+ original concentration had significant influence on Cd2+ removal percentage. Cd2+ removal percentage decreased significantly with the increasing of Cd2+original concentration whether the original pH value be adjusted to 3.0 or without adjustment. The results showed that the Cd2+ removal process followed the first order reaction because the reaction order was from 0.803 to 0.996. The apparent reaction rate constant between Cd2+ and NSIS was from 0.0025 to 0.1000 (mg·L?1)1-n·min?1. Compared with SIS reduced by charcoal reduction, NSIS deoxided by hydrogen possessed higher activity, and could remove the same quantity of Cd2+ within a shorter period of time. 相似文献
289.
在突发环境污染事件和区域生态风险筛查中迫切需要环境样品中重金属离子的快速检测技术手段。环境样品中重金属离子的快速检测技术有电化学方法和生物学方法。电化学检测方法主要是阳极溶出伏安法(AnodicStripping Voltammetry,ASV),可以同时检测多种重金属离子,有标准化认证的产品,但是检测成本相对较高。随着纳米粒子技术(Nanoparticles,NPs)和石英微天平分析技术(Quartz Crystal Microbalance,QCM)的引入,ASV法的检测成本将不断降低;生物检测方法包括免疫检测(Immunoassay,IA)和功能DNA(Functional DNA)检测技术。重金属离子的免疫检测技术样品通量大,检测成本低,已经广泛用于食品行业,其中汞离子的免疫检测方法已经成为环境样品标准检测方法之一。免疫检测传感器技术将拓展重金属离子的快速检测的应用空间。功能DNA传感器检测的研究为重金属离子的快速检测提供了新的技术手段,但是这些仅限于实验室研究,还没有达到实际应用的水平。 相似文献
290.