Study on soil denitrification in an agricultural catchment in southeasten area of Fujian province

反硝化是一个重要的生物化学过程，是氮生物地球化学循环的重要环节。在维持流域、乃至全球氮素平衡方面发挥着重要作用。土壤反硝化的中间产物之一的N2O气体，是一种温室气体，对大气臭氧层具有较大的破坏作用。另外，反硝化还影响其他重要的生物地球化学过程。因此，反硝化研究具有重要的现实意义。 随着经济的高速发展、自然资源的不断消耗和生态环境的不断恶化，全球环境问题日益突出，温室效应已十分明显。作为温室气体之一的N2O对全球气候变化有着重要的影响。目前，有关N2O的研究已成为温室效应与全球气候变化研究的焦点之一。流域作为特殊的一个生态系统，对全球氮素循环研究具有十分重要的研究意义。 本研究结合多学科知识...The nitrogen element is one of nutritive elements, also is the element that the primary producer grows needs. As one of important nutritive elements in the ecosystem, the nitrogen element is affecting crops' growth, also affecting the water body’s quality. Denitrification is an important biochemistry process, is one of the important links in nitrogen biogeochemistry circulation. Deinitrificatio...学位：工学硕士院系专业：海洋与环境学院环境科学与工程系_环境科学学号：20043406

Testing GLEAMS for Nitrate Leaching Modeling in an Agricultural Catchment of Southeast China

利用我国东南亚热带地区农业小流域不同土地利用方式的硝氮渗漏淋失实测数据检验了GLEAMS(Groundwater Loading Effects of Agricultural Management Systems)模型在该地区的适用性。通过现场试验和实地调查并结合模型手册,获取模型所需的水文和营养盐参数,参考模型参数的敏感性分析结果对模型进行调试。结果表明模型对水稻田除外的其它土地利用方式的硝氮渗漏淋失模拟效果较好。水稻田渗漏模拟效果差的主要原因在于模型的水分平衡方程不能反应水稻田长期淹水的实际情况。模型模拟结果的精度可以接受,从而验证了GLEAMS模型在该流域的适用性。GLEAMS(Groundwater Loading Effects of Agricultural Management Systems)model was introduced to test and validate nitrate leaching in an agricultural catchment in southeast China.Field experiments were performed under different landuses such as paddy,bananas and vegetables,in Wuchuan catchment of Fujian Province with the area of 9.6 km2.Eight boreholes were drilled and monitoring pipes were installed for continuous monitoring of nitrate leaching from April to December in 2002.The hydrologic and nutrient parameters of GLEAMS model were extracted based on measurements and experiments during the main crop growing season.Model parameters were tuned to achieve desired agreements between measurements and model simulations based on sensitivity analysis.After calibration and validation,the model generally had acceptable performances in simulating nitrate leaching throughout the landuses with an exception in paddy field.The model simulations can be used to specifically establish best management practices for nutrient management and pollution mitigation in the catchment.国家自然科学基金(40671116;40301045

Nitrogen and phosphorus pollution from urban stormwater runoff in Xiamen City

以厦门岛为研究对象,通过收集代表性样点的降雨径流水样,研究了厦门城市降雨径流中氮、磷浓度及输出特征。结果表明,来源不同的城市降雨径流中氮、磷浓度差异较大,溶解态总氮、硝态氮、氨态氮与总磷的含量分别为1.96~6.77、0.62~4.89、0.35~1.18和0.04~0.66 mg.L-1。降雨过程中氮、磷浓度总体上呈下降趋势,氮浓度波动较大,磷相对稳定。城市降雨径流氮、磷污染受降雨强度、车流量等多种因素影响。城市道路、商住区及工业区径流中氮、磷浓度较高,是城市非点源污染的主要来源,因此对这些区域应重点控制管理。In this study,the stormwater samples of 4 storm events occurred in April and May 2005 were collected from different representative sites including road,roof,and residential,commercial and industrial districts in Xiamen Island.All the samples were delivered to laboratory within 24 h,and their NO_3~——N,NH_4~+-N, dissolved total nitrogen(TN),and total phosphorus(TP) contents were analyzed.The water quality data showed there was a significant difference in the nitrogen and phosphorous concentrations of the stormwater runoff from different sites, with the mean value of TN,NO_3~——N,NH_4~+-N and TP ranged as 1.96-6.77, 0.62-4.89,0.35-1.18 and 0.04-0.66 mg·L~(-1),respectively.In general,the nitrogen and phosphorus concentrations decreased gradually in the process of precipitation due to water dilution,but the nitrogen concentration fluctuated more intensively than phosphorus.Many factors such as precipitation intensity,land cover and vehicle exhaust affected the patterns of nitrogen and phosphorus transportation.The urban stormwater runoff collected from road and commercial and industrial districts contributed a higher nutrient loading,and thus,the management of urban stormwater runoff should be focused on these sites.国家自然科学基金资助项目(40301045)

Denitrification Determination in soil of Wu Chuan Agricultural Catchment and the Control Measure

反硝化作用是土壤氮素转化的一个重要过程,为探明五川流域内的农业土壤的反硝化作用强度及其影响因素,利用乙炔抑制-原状土柱培养法对其进行测定。通过3次试验测定,发现五川流域农业土壤具有较强的反硝化作用强度,在种植季节,土壤平均反硝化作用强度为0.1kgN·hm-2·d-1,最高达到0.6kgN·hm-2·d-1,其中蔬菜地反硝化作用强于其他土地利用类型。反硝化作用同土壤的NO3-含量、含水量、温度以及pH都存在正相关关系,它们是流域土壤反硝化作用的主要影响因子。五川流域农业土壤经由反硝化作用氮损失量占流域平均施肥量的16%,高于国内其他地区。针对五川流域的环境和农业经济特点,提出了控制反硝化作用的措施:在温度较低的夜间进行施肥灌溉宜以防止氮肥损失,用农村富余的厩肥代替化肥以减轻反硝化作用的发生,同时加大节水灌溉力度。Denitrification in soil is the main pathway of gaseous nitrogen loss in the catchments.In order to find out the denitrification flux in top-soil and the affecting factors in Wu Chuan catchment,the denitrification rate of top-soil was determined using the acetylene inhibition-intact soil core technique for 5 months.Three times of the denitrification experiment were carried out from Dec.15th 2005 to Apr.18th 2006,at the same time,the chemical and physical properties of the soils were also measured during every experiment.The soils in Wu Chuan catchment belong to typical Haplic red soil,with the chemical and physical properties suitable for denitrification and the organic matter,total N,NO3-N and pH of the soils being 9～25 g·kg-1,0.4%～7.9%,1.5～6.8 mg·kg-1 and 4.9～5.7,respectively.The results indicated that denitrification of the soil showed temporal and spatial variations.The denitrification rate in uplands of the catchment was higher than that in any other places,and was enhanced when there were many rains and when the soil temperature was high.The flux of denitrification was mostly related with fertilization,soil moisture,air temperature and pH.Air temperature affected denitrification significantly.The gaseous N loss rate through denitrification represented about 16% of the fertilizer applied in the catchment scale.Also,the denitrification flux of the top-soil in Wu Chuan catchment was much higher than that in other places of China,and the denitrification rate of soils in south was higher than that in north.The soils in Wu Chuan catchment may be the source of atmospheric nitrous oxide gas.Since the high level of agricultural economic development in Wu Chuan catchment and the frequently used fertilizers,the flux of fertilizers is much higher than other agricultural region in China.Based on the environmental characteristics and agricultural economy in Wu Chuan catchment,the following control measures should be adopted:(1) fertilization and irrigation in the low-temperature night to prevent fertilizer loss;(2) utilization of livestock waste instead of fertilizer to inhibit denitrification;(3) popularizing economical irrigation to avoid reductive situation in the soil.国家自然科学基金(40301045和40671116

Field study on denitrification in soil of south Fujian agricultural catchment

土壤反硝化是流域土壤氮损失的重要途径之一。利用乙炔抑制培养法对五川流域内表层土壤的反硝化进行测定,研究发现,闽南农业小流域土壤具有较强的反硝化作用强度,在种植季节土壤平均反硝化作用强度为N 0.1 kg/(hm2.d),最高达到N 0.6 kg/(hm2.d),其中蔬菜地反硝化作用强于其他土地利用类型。反硝化作用同土壤的含水量、温度以及NO3-含量都存在有正相关关系,温度是流域土壤反硝化作用的最主要影响因子。五川流域土壤经由反硝化作用氮损失量占流域施肥量的16%,稍高于国内其他地区。Denitrification from soils is the main pathway of gaseous loss for nitrogen in the catchments.We measured the denitrification rate from the top-soil in Wuchuan catchment by using the acetylene inhibition technique.The result of this experiment indicated that denitrification of the soil had the temporal and spatial variance.The rate of denitrification that occurred in uplands of the catchment was higher than any other places,and denitrification was enhanced when there were many rains and when the soil temperature was high.The flux of denitrification was mostly related with fertilization,soil moisture and air temperature.Air temperature was top-dressed affected denitrification significantly.The gaseous N loss rate through denitrification represent about 16% of the fertilizer applied in the catchment scale.国家自然科学基金(40301045

Field Study on Nitrogen Mineralization in Soil of South Fujian Agricultural Catchment

用原位培养法对五川流域内的香蕉地、菜地、香蕉地与菜地间作地、林地、甘蔗地土壤的氮矿化作用进行了研究,结果发现不同土地利用方式下土壤氮矿化速率平均为N0.11mgkg-1d-1,其中香蕉地土壤氮矿化最高可达N1.47mgkg-1d-1;土壤硝化速率平均为N0.27mgkg-1d-1,其中菜地下土壤硝化作用强度最高可达N0.69mgkg-1d-1。土壤矿化作用同土壤湿度、温度、C/N、土壤肥力存在明显的相关关系。不同土地利用方式下温度是土壤氮矿化最主要的影响因子。闽南流域土壤年矿化量平均为N240kghm-2,部分样地最高可达N850kghm-2,而年施肥量平均N650kghm-2。相比较而言,说明了土壤矿化是我国南方流域农业土壤氮素的重要来源。Nitrogen (N) mineralization determines soil N availability, which limits plant growth and productivity. In this study, a field experiment was conducted to study soil nitrogen mineralization function of five different land use patterns in the Wuchuan catchment of Nanjing county of Zhangzhou city. The results showed that the average net nitrogen mineralization rate was 0.11mg N kg-1 d-1, and the highest of five different land use patterns was in the banana (about 1.47mg N kg-1 d-1). The soil average nitrification rate was 0.27mg N kg-1 d-1, and the highest of five different land use patterns was in the vegetable (about 0.69mg N kg-1 d-1). The soil nitrogen rate has obvious correlated relation. And the temperature was major factor in the five different land use patterns. The annual mineralization rate in the catchment was about 240kg N hm-2, the highest rate was about 850kg N hm-2 in some land use patterns, but the annual average fertilization was 650kg N hm-2. It could explain the soil nitrogen mineralization as a major N source in the agricultural soil in the catchment of south of China.国家自然科学基金项目40671116和40301045资

Distribution of Littoraia melanostoma Gray (Littorinidae) and Nerita lineata Gmelin (Neritadae) in rehabilitated mangroves.

研究了福建九龙江河口不同林龄、不同红树种类的人工林中黑口滨螺(Littoraiamelanostoma)和黑线蜒螺(Neritalineata)的分布情况.结果表明,黑线蜒螺主要分布于秋茄林内,且其生物量随林龄增加而增加;桐花树林内黑口滨螺的生物量和密度均大于林龄相近的秋茄林,但个体大小则小于秋茄林.黑口滨螺的生物量在桐花树林内随林龄增加呈现先增加后减少的趋势,而在秋茄林内则随林龄增加而减少.这种差异性反映了人工红树林植物种类及其演替过程对腹足类动物分布的影响.An investigation was made in April and July 2005 on the abundance and biomass of Littoraia melanostoma (Littorinidae) and Nerita lineata (Neritadae) in the rehabilitated mangrove forests with different mangrove species and stand ages at the Jiulongjiang Estuary of Fujian Province. The results showed that Nerita lineata was more abundant in mature stands,and had greater bio mass and density in Kandelia candel stand than in Aegiceras corniculatum sta nd. A. corniculatum stand had greater density and biomass of L. melanostoma than K. candel stand,when the two stands had similar ages. In A. corniculatum stands,the biomass of L. melanostoma increased with the age of younger stands; while in K. candel stands,it decreased with the development of the forests. Different habitation patterns of the two snails in different mangrove stands indicated that N. lineate had a strong inhabitation preference for mature K. candel forest,while L. melanostoma was apt to inhabit in younger A. corniculatum forests.国家自然科学基金项目(40476040);; 福建省自然科学基金资助项目(D0410006)

一种钼掺杂的纳米二氧化钛催化剂的制备方法

本发明涉及半导体纳米材料技术领域，特别涉及一种钼掺杂的纳米二氧化钛催化剂的制备方法，包括：采用含钛化合物为前驱体溶于无水低级醇中，在该溶液中掺入金属钼粉，再快速加入氨水，使得含钛化合物经水解、缩聚反应得到钛-钼凝胶，烘干，冷却，研磨成粉后煅烧，即得钼掺杂的纳米二氧化钛催化剂。本发明方法无需调节pH值，快速、简便地制备了具有良好吸附和催化活性的二氧化钛光催化剂