氧化塘深度对猪场厌氧消化液后处理的影响   总被引：1，自引：0，他引：1  

温泉  李正山  邓良伟 《中国沼气》2011,29(5)

采用小试装置对3个不同深度氧化塘处理猪场厌氧消化液的效果进行了研究,结果表明:当平均气温为21.9℃,停留时间在80 ～110天,进水负荷为0.05 m3·m-2d-1的条件下,氧化塘对NH4-N的去除率达到了90％以上,CODcr,TP的去除率分别为50％,40％.硝化作用和藻类的吸收是氧化塘去除NH4-N的主要方式,沉淀作用则是CODcr和TP的主要去除方式,在较长停留时间下,微生物对于溶解性CODcr的分解和同化也能提供一定的去除效果.当平均气温为21.9℃,在表面负荷为0.05 m3·m-2d-1的条件下,有效深度为0.3m和0.7m的氧化塘面积去除负荷分别为1.41 g·m-2d-1,1.49 g·m-2d-1,容积去除负荷分别为4.7g·m -3d-1,2.8g·m-3d-1.虽然较深氧化塘具有较高的面积去除负荷,但较浅的氧化塘却有更高的容积去除负荷.  相似文献   

Denitrification potential of intermittently saturated floodplain soils from a subtropical perennial stream and an ephemeral tributary     

Christine S. Fellows  Heather M. Hunter  Claire E.A. Eccleston  David W. Rassam  Philip M. Bloesch 《Soil biology & biochemistry》2011,43(2):324-332

Denitrification has the potential to remove excess nitrogen from groundwater passing through riparian buffers, thus improving water quality downstream. In regions with markedly seasonal precipitation, transient stream flow events may be important in saturating adjacent floodplain soils and intermittently providing the anaerobic conditions necessary for denitrification to occur. In two experiments we characterised the denitrification potential of soils from two contrasting floodplains that experience intermittent saturation. We quantified under controlled laboratory conditions: 1) potential rates of denitrification in these soils with depth and over time, for a typical period of saturation; and 2) the influences on rates of nitrate and organic carbon. Treatments differed between experiments, but in each case soil-water slurries were incubated anaerobically with differing amendments of organic carbon and nitrate; denitrification rates were measured at selected time intervals by the acetylene-block technique; and slurry filtrates were analysed for various chemical constituents. In the first experiment (ephemeral tributary), denitrification was evident in soils from both depths (0-0.3 m; 0.3-1.1 m) within hours of saturation. Before Day 2, mean denitrification rates at each depth were generally comparable, irrespective of added substrates; mean rates (Days 0 and 1) were 5.2 ± 0.3 mg N kg dry soil⁻¹ day⁻¹ (0-0.3 m) and 1.6 ± 0.2 mg N kg dry soil⁻¹ day⁻¹ (0.3-1.1 m). Rates generally peaked on Days 2 or 3. The availability of labile organic carbon was a major constraint on denitrification in these soils. Acetate addition greatly increased rates, reaching a maximum in ephemeral floodplain soils of 17.4 ± 1.8 mg N kg dry soil⁻¹ day⁻¹ on Day 2: in one deep-soil treatment (low nitrate) this overcame differences in rates observed with depth when acetate was not added, although the rate increase in the other deep-soil treatment (high nitrate) was significantly less (P ≤ 0.01). Without acetate, peak denitrification rates in this experiment were 6.9 ± 0.4 and 2.8 ± 0.2 mg N kg dry soil⁻¹ day⁻¹ in surface and deep soils, respectively. Differences in rates were observed with depth on all occasions, despite similar initial concentrations of dissolved organic carbon (DOC) at both depths. Levels of substrate addition in the second experiment (perennial stream) more closely reflected natural conditions at the site. Mean denitrification rates were consistently much higher in surface soil (P ≤ 0.001), while the source of water used in the slurries (surface water or groundwater from the site) had little effect on rates at any depth. Mean rates when all treatments retained nitrate were: 4.5 ± 0.3 mg N kg dry soil⁻¹ day⁻¹ (0-0.3 m depth); 0.8 ± 0.3 mg N kg dry soil⁻¹ day⁻¹ (0.3-1.0 m); and 0.6 ± 0.1 mg N kg dry soil⁻¹ day⁻¹ (1.8-3.5 m). For comparable treatments and soil depths, denitrification potentials at both sites were similar, apart from higher initial rates in the ephemeral floodplain soils, probably associated with their higher DOC content and possibly also their history of more frequent saturation. The rapid onset of denitrification and the rates measured in these soils suggest there may be considerable potential for nitrate removal from groundwater in these floodplain environments during relatively short periods of saturation.  相似文献   

排灌输水隧洞正常水深的简捷算法     

赵延风  王正中  方兴  刘计良  洪安宇 《排灌机械》2011,29(6):523-528

为了使标准城门洞形断面正常水深的求解具有简单的显函数计算公式,对标准城门洞形断面正常水深的基本方程进行恒等变形,将水面位于底角圆弧段和顶弧段正常水深的超越方程以及水面位于侧边直线段正常水深的高次方程,变成无量纲化正常水深与已知量综合参数的单变量函数方程.引入准线性函数的概念并将准线性函数作为标准模板,再对正常水深的单变量函数方程应用准线性函数标准模板,在工程常用范围即无量纲化正常水深y∈[0.051,.80]范围内进行优化计算及准线性函数逼近,得到了超越方程和高次方程的替代函数方程,替代函数具有类似于线性函数形式,即正常水深的准线性显函数表达式,并进行误差分析.结果表明,在隧洞底部圆弧段正常水深的最大相对误差小于0.36%,侧边直线段正常水深的最大相对误差小于0.31%,顶弧段正常水深的最大相对误差小于0.39%,说明准线性公式在隧洞有效水深范围内计算的水深准确度较高,可为排灌输水隧洞的断面设计及实现渠道水位控制时确定均匀流水深提供参考.  相似文献   

地下水埋深对冬小麦和春玉米产量及水分生产效率的影响   总被引：3，自引：0，他引：3  

刘战东  肖俊夫  牛豪震  贾云茂 《干旱地区农业研究》2011,29(1):29-33

利用排水式蒸渗仪,通过设置6种地下水位控制处理(地下水位埋深分别为0.5、1.0、1.5、2.0、2.5 m和3.0 m)试验,探讨了太原盆地不同地下水埋深对冬小麦和春玉米生长指标、产量、产量构成因素及水分生产效率(WUE)的影响.结果表明,地下水埋深对冬小麦和春玉米千粒重的影响较小,对冬小麦干.物质重影响显著(P=0...  相似文献   

干旱区地下水埋深空间分布对天然植被覆盖度影响研究—以塔里木河下游为例     

郭玉川  杨鹏年  李霞 《干旱区资源与环境》2011,(12):161-165

以塔里木河下游输水河畔的植被覆盖度和地下水埋深为研究对象,建立遥感反演模型获取研究区植被覆盖度的空间分布,建立地下水数值模型模拟与覆盖度同时段的埋深空间分布,采用空间分析方法对覆盖度和埋深的空间分布数据进行分析,获取不同埋深区间所对应的植被覆盖度,并得出以下结论：研究区植被覆盖度在地下水0～20m的埋深区间上呈阶梯状分...  相似文献   

腾格里沙漠南缘3种优势植物种子出苗对土壤类型和沙埋的响应     

樊宝丽  马全林  张德魁  安婧荣 《干旱区研究》2011,28(6):1038-1044

沙米（Agriophyllum squarrosum）、沙蒿（Artemisia sphaerocephala）和油蒿（Artemisia ordosica）分别是腾格里沙漠南缘不同植被演替阶段的3个优势物种,2009年5～6月在大田盆栽条件下,设计了2种土壤类型和0 cm,1 cm,2 cm,3 cm,4 cm,6 ...  相似文献   

泥石流入汇主河淤积规律的水槽试验研究   总被引：1，自引：0，他引：1  

敖汝庄郭志学  曹叔尤 《水土保持学报》2004,18(4):196-199

以试验为基础,研究了泥石流入汇主河后淤积规律,主要探讨了淤积量及淤积分布问题。通过试验分析认为,泥石流入汇主河后的淤积量基本随流量比的增大而增大,就其淤积速率而言,有先增大后减小的变化规律。淤积量在流量比大约为0.5时出现峰值,在流量比为0.65时出现谷值,淤积量与流量比关系变化曲线以倾斜向上的直线为对称轴,呈倾斜向上的正弦波形。各工况下淤积范围基本不变,但试验中反映出,淤积范围有随交汇角增大而增大的趋势。  相似文献   

基于模糊集理论提取土壤—地形定量关系及制图应用   总被引：8，自引：1，他引：8  

赵量  赵玉国  李德成  孙孝林  张甘霖 《土壤学报》2007,44(6):961-967

通过对研究区地形因子的模糊聚类,提取了地形因子组合与特定土壤属性的定量隶属度关系,然后对隶属度高值区土壤进行目的性采样为隶属度函数赋值,制作研究区土层厚度连续分布图。通过野外实地验证,将观测值与图中预测值比较,结果显示该方法制图精度在82%左右,具有一定的可靠性。进一步考察认为该模型在地形部位较低,地势较为平坦,土壤发育较好,土层较厚,成土环境相对稳定的地区预测效果更好,适用性更强。该方法能提高土壤制图效率,降低制图成本,提高制图精度,对土壤微域变异的表现更为详细,图面信息负载量更高。应用该方法制作大比例尺土壤详图不失为土壤调查与制图领域一种可行的新方法。  相似文献   

秸秆还田深度对黑土腐殖质和酶活性的影响   总被引：2，自引：0，他引：2       下载免费PDF全文

矫丽娜  李志洪  殷程程  崔钰曼  张婷 《中国土壤与肥料》2015,(2):17-21

在田间条件下对耕地黑土3个土层(0~15、15~30、0~30 cm)进行玉米秸秆还田试验,研究不同秸秆还田深度土壤腐殖质各组分含量、土壤酶活性的变化及其相关性。结果表明:还田深度0~15、15~30、0~30cm土壤总有机碳含量与初始相应层次土壤分别增加9.5%、9.9%、10.7%,与0~15 cm相比,秸秆还田深度为15~30 cm时,有利于土壤有机碳的积累。与初始相应层次土壤比,未秸秆还田的土壤总有机碳含量降低了5.8%。土壤各组分有机碳含量与土壤蔗糖酶活性之间显著(或极显著)相关,土壤胡敏素碳含量与土壤过氧化氢酶活性之间显著相关,土壤富里酸碳含量与土壤脲酶活性之间显著相关。  相似文献   

The effect of water table depth on emissions of N₂O from a grassland soil     

K. E. Dobbie  & K. A. Smith 《Soil Use and Management》2006,22(1):22-28

Nitrous oxide (N₂O) emissions were measured by the closed chamber technique from five plots along a transect in a nitrogen‐fertilised grassland, together with soil water content, soil temperature and water table depth, to investigate the effect of water table depth on N₂O emissions. N₂O fluxes varied from <1 g N₂O‐N ha^?1 day^?1 to peaks of around 500–1200 g N₂O‐N ha^?1 day^?1 after N fertiliser applications. There was no significant difference in overall average water table depth between four of the five plots, but significant short‐term temporal variations in water table depth did occur. Rises in the water table were accompanied by exponential increases in N₂O emissions, through the associated increases in the water‐filled pore space of the topsoil. Modelling predicted that if the water table could be managed such that it was kept to no less than 35 cm below the ground surface, fluxes during the growing season would be reduced by 50%, while lowering to 45 cm would reduce them by over 80%. The strong implication of these results is that draining grasslands, so that the water tables are only rarely nearer to the surface than 35 cm when N is available for denitrification, would substantially reduce N₂O emissions.  相似文献