Simulating methane emission from a Chinese rice field as influenced by fertilizer and water level     

Z. Yu  X. Shangguan  D. Pollard  E. J. Barron 《水文研究》2003,17(17):3485-3501

Natural and agricultural wetlands are considered to be the major sources of global atmospheric methane (CH₄). A one‐dimensional model was developed to simulate methane emission and used to examine the influence of various physical processes on the rate of methane emission. Three processes involved in the methane emission are implemented in the model: production, reoxidation and transport. Three transport pathways were considered: diffusion across water–air or soil–air interfaces, ebullition and diffusion through plants. These pathways are influenced by soil properties, plant growth, water‐table conditions, temperature and external inputs (e.g. fertilizer). The model was used to examine the seasonal variation of the methane emission at a rice field in Hunan, China, which was observed during a field experiment for consecutive (early and late) rice seasons in 1992. The observed seasonal variations of methane emission, and role of plants in transporting methane to the atmosphere, are captured by the model simulation. Further model applications were conducted to simulate effects of fertilizer and water‐level condition on the methane emission. The results indicate that unfermented organic fertilizer produces a higher methane emission rate than mineral fertilizer. The simulations with treatments of a deep‐water covering and constant moisture reduced the methane emission. The rice field study provides a framework for further development of the model towards simulations based on spatially distributed variables (e.g. water table, soil temperature and vegetation) at a regional scale. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Is Precipitation the Dominant Controlling Factor of High Inorganic Nitrogen Content in the Changjiang River and Its Mouth？   总被引：1，自引：1，他引：0  

沈志良 《中国海洋湖沼学报》2003,21(4):368-376

The main reasons for the high content of inorganic N and its increase by several times in the Changjiang River and its mouth during the last 40 years were analysed in this work. The inorganic N in precipitation in the Changjiang River catchment mainly comes from gaseous loss of fertilizer N, N resulting from the increases of population and livestock, and from high temperature combustions of fossil fuels. N from precipitation is the first N source in the Changjiang River water and the only direct cause of high content of inorganic N in the Changjiang River and its mouth. The lost N in gaseous form and from agriculture non-point sources fertilizer comprised about 60% of annual consumption of fertilizer N in the Changjiang River catchment and were key factors controlling the high content of inorganic N in the Changjiang River mouth. The fate of the N in precipitation and other N sources in the Changjiang River catchment are also discussed in this paper.  相似文献   

Interactions between grey seal (Halichoerus grypus), Atlantic salmon (Salmo salar), and harvest controls on the salmon fishery in the Gulf of Bothnia     

Jounela  P.; Suuronen  P.; Millar  R.B.; Koljonen  M-L. 《ICES Journal of Marine Science》2006,63(5):936-945

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硅酸盐细菌解钾作用机理的综合效应   总被引：44，自引：5，他引：44  

连宾  傅平秋  莫德明  刘丛强 《矿物学报》2002,22(2):179-183

硅酸盐细菌能释放土壤含钾硅酸盐矿物中的磷、钾、硅等元素，直接供给植物生长利用，同时亦具有固氮能力。这为挖掘土壤潜在肥力、发展可持续农业提供了一条新的思路。本文分析了硅酸盐细菌对钾长石、伊利石的解钾作用过程，细菌-矿物复合体的形成，细菌对矿物的溶蚀作用，矿物晶体结构与细菌的解钾作用关系，复合体微环境的变化对细菌解钾作用的影响以及细菌对K^ 的主动吸收等，从微生物矿物学的角度讨论了硅酸盐细菌对含钾硅酸盐矿物解钾作用的机理问题，提出了硅酸盐细菌解钾作用综合效应的看法，并就农业生产上的利用问题指出，应根据当地的土壤环境，选择适宜的生产菌种和吸附剂，并配合使用其它化学肥料和有机肥料。  相似文献   

The Mount Parnitha (Athens) Earthquake of September 7, 1999: A Disaster Management Perspective     

Pomonis  Antonios 《Natural Hazards》2002,27(1-2):171-199

Natural Hazards - Strong earthquakes in the proximity of densely inhabited urban areas pose one ofthe most complicated disaster management situations faced by societies today. Herethe experience...  相似文献   

中国化肥利用率的区域分异   总被引：77，自引：2，他引：77  

陈同斌  曾希柏  胡清秀 《地理学报》2002,57(5):531-538

据全国各县近10年的化肥施用量和粮食产量数据，并从不同年份单位播种面积粮食产量和肥料施用量的变化，求出相应不施肥产量和通过施肥可能达到的最高产量，并以上述结果为基础计算出该地区化肥利用率，研究结果表明：当前我国化肥施用的地区差异明显，施用量较集中范围是180－270kg/hm^2和90－180kg/hm^2，部分地区的化肥施用已经过量；单位化肥的粮食产出率主要集中在10－30kg/kg，化肥利用率大多集中在15％－35％，且与化肥施用量有关，按地区统计，高施肥量区化肥施用明显过量，平均达339kg/hm^2，是全国平均用量（262kg/hm^2)的1．29倍，中施肥量区单位面积化肥平均施用量为252kg/hm^2，略低于全国平均水平，低施肥量区则仅为178kg/hm^2，是全国平均的67．8％，我国单位化肥的生产效率及化肥利用率均以低施肥量区最高，分别为17．5kg/kg和39．8％，中施肥量区为13．7和36。  相似文献   

滇池农村固体废物和化肥流失治理试验研究   总被引：5，自引：1，他引：5  

戴丽  郭慧光  汤承彬  罗丽 《云南地理环境研究》2002,14(2):70-79

怎样合理处置农村固体废物和减少农田化肥流失一直是农村面源污染控制的难题之一。该研究将农村固体废物的处理与减少化肥施用措施有机结合，利用微生物复合发酵剂和农村固体废物生产活性肥料，开展了一系列农业种植试验和数据监测，在此基础上，提出了一套实用性强、效果好的控制农业固体废物和化肥流失污染的对策措施。  相似文献   

长效钾肥产业化与农业可持续发展     

钱发军  赵凤兰  邓挺  刘夏茹  豆来平 《地域研究与开发》2003,22(2):67-69

我国钾肥需求量逐年增加，80％需要进口，但同时又有大量的低品位非水溶性钾矿资源没有利用，利用非水溶性钾矿生产长效钾肥既能缓解钾肥短缺的矛盾，又可以解决普通钾肥对环境的污染和破坏。长效钾肥原料分布广，生产和施用技术简单，成本低，易于推广普及形成产业化，其对农业可持续发展将会产生重要的促进作用。  相似文献   

洪水对非防洪工程建设项目影响评价方法研究          下载免费PDF全文

陆桂华  陆宝宏  张行南  宋兰兰 《水科学进展》2003,14(4):480-484

讨论了洪水对洪泛区或滞蓄洪区中非防洪工程建设项目影响评价方法,包括洪灾直接经济损失和间接经济损失的估算方法,洪灾发生时含有有毒物质的非防洪工程建设项目对环境的影响,以及对地下水的污染等影响评价方法.这些方法是洪水对非防洪工程建设项目影响评价的核心,也是整个影响评价的重点和难点所在.这些方法可为制定洪水对洪泛区非防洪工程建设项目影响评价指南或规范提供科学依据.  相似文献   

March 1990 Hailstorm Damage in Sydney,Australia     

Andrews  Kylie E.  Blong  Russell J. 《Natural Hazards》1997,16(2-3):113-125

On 18 March 1990, an intense hailstorm in Sydney, New South Wales, Australia caused insured damage valued at A$million – the third most expensive loss event in Australian insurance history.While damage was widespread with claims for buildings spread across more than 130 postcodes, 20% of the claims came from just two postcodes. The proportion of dwellings of brick construction that made a claim was significantly less than the proportion of policies for this type of construction. Fibro (fibre-cement), timber and aluminium-clad dwellings are more likely to sustain damage than brick buildings in this type of storm.Hail caused the majority of damage to exterior building items while water damage more commonly affected interior building items and contents. While the repair of Interior building items such as ceilings and walls cost more than contents damage on average, the repair/replacement costs of contents contributed more to the total costs. Damage to window glass and roofs together made up more than 50% of the total claim.  相似文献