Can arbuscular mycorrhiza and fertilizer management reduce phosphorus runoff from paddy fields?

Our study sought to assess how much phosphorus (P) runoff from paddy fields could be cut down by fertilizer management and inoculation with arbuscular mycorrhizal fungi. A field experiment was conducted in Lalin River basin, in the northeast China: six nitrogen–phosphorus–potassium fertilizer levels were provided (0, 20%, 40%, 60%, 80%, and 100% of the recommended fertilizer supply), with or without inoculation with Glomus mosseae. The volume and concentrations of particle P (PP) and dissolved P (DP) were measured for each runoff during the rice growing season. It was found that the seasonal P runoff, including DP and PP, under the local fertilization was 3.7 kg/ha, with PP, rather than DP, being the main form of P in runoff water. Additionally, the seasonal P runoff dropped only by 8.9% when fertilization decreased by 20%; rice yields decreased with declining fertilization. We also found that inoculation increased rice yields and decreased P runoff at each fertilizer level and these effects were lower under higher fertilization. Conclusively, while rice yields were guaranteed arbuscular mycorrhizal inoculation and fertilizer management would play a key role in reducing P runoff from paddy fields.     

下凹式绿地在降雨径流控制中的应用研究

下凹式绿地具有蓄渗雨水、削减洪峰流量、净化雨水、防止土壤侵蚀等优点,且投资少,是一种能同时满足环境、生态、经济等多重效应的新型雨水利用措施;它的应用将有效缓解城市水资源匮乏和降雨地表径流造成的面源污染,同时能在一定程度上防止城市内涝.在介绍下凹式绿地对降雨径流控制的基础上,着重综述了下凹式绿地对雨水的蓄渗、净化作用及其设计方面的研究进展.     

Respective contributions of point and non-point sources of E. coli and enterococci in a large urbanized watershed (the Seine river, France)

Because the large rivers of the Seine watershed have a low microbiological water quality, the main sources of fecal contamination were investigated in the present study. The inputs of the point (wastewater treatment plants (WWTPs) effluents) and non-point sources (surface runoff and soil leaching) of fecal bacteria were quantified for Escherichia coli and intestinal enteroccoci used as bacterial indicators. In order to assess the contamination through non-point sources, fecal indicators abundance was estimated in samples collected in small streams located in rural areas upstream from all point sources; these small rivers were characterized by the land use of their watershed. Bacterial indicator numbers were also measured in effluents of WWTPs, some using classical treatment (settling followed by activated sludge process) and some using an additional disinfection stage (UV irradiation). These data were used to estimate the respective importance of each type of source at the scale of the whole Seine river watershed taking into account the land use and the population density. It shows the predominant importance of the point sources of fecal indicator bacteria at the scale of the whole watershed. In a scenario in which activated sludge treatment would be complemented with UV in all WWTPs located in this watershed, the non-point sources of fecal indicator bacteria would be dominant.     

Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models

Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships. The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales. Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the Queensland and Australian Governments’ Reef Water Quality Protection Plan.     

酸/碱改性香蒲生物炭对水中磷的去除及其机制研究

雨水径流中存在的磷污染问题严重威胁生态环境,而传统的雨水径流处理设施,如雨水花园、渗滤沟等,对磷的去除率较低且成本较高.以湿地中收割的香蒲为原材料,酸改性后制备的生物炭（TH7）的除磷效果非常好,明显优于碱改性生物炭（TOH7）：与原生物炭（T7）相比,酸改性生物炭大大提高了磷的去除效率,可从T7的65%提高至94%,而碱改性生物炭无除磷效果.TH7的表面孔隙发达,比表面积高达434.2m²·g^-1,对磷的吸附符合Freundlich模型和伪二级动力学模型,其吸附属于物理化学吸附,具体的机制为孔隙填充、表面化学沉淀、氢键结合.研究表明,以香蒲为原料制备的改性生物炭是一种效果优越的除磷吸附剂,可应用于植草沟、雨水花园等以填料为主要吸附层的径流处理设施中.     

城中村雨水污水完善改造方案浅析

结合深圳盐田区城中村污水完善改造设计及施工服务中所遇到的问题,提出为彻底解除雨水污水混流现象而采取的措施和方法,以作为今后城中村雨水污水分流制改造过程中的借鉴或参考。     

HYDROCLIMATIC VARIABILITY IN THE ROCKY MOUNTAINS1

ABSTRACT: The spatial and temporal variability of hydroclimatic elements were investigated in the central and northern Rocky Mountains (Colorado, Idaho, Montana, Utah, and Wyoming) during the 1951–1985 period. The three hydroclimatic elements studied were total water-year (October 1-September 30) streamflow (ST), winter (October 1-March 31) accumulated precipitation (PR), and April 1 snowpack (SN). An analysis of 14 virgin watersheds showed wide spatial djfferences in the temporal variability of SN, PR, and ST, and these were found to be caused largely by basin exposure to moist air flows. The more stable (low variability) basins were those exposed to prevailing northerly to westerly flow, while unstable (high variability) basins were exposed to occasional southwesterly to southeasterly moist flow. Snowpack was the better indicator of ST in 11 of the 14 watersheds, explaining 37 to 87 percent of the ST variance. Analysis of the spatial variability, based on all SN and PR data from across the study area, revealed 11 discrete climatic regions. Both SN and PR exhibited coherent regions of stable and unstable temporal variability. The average variability between stable and unstable regions differed by a factor of two, and the differences were best explained by the exposure of the mountain barrier to moist air flows.     

MINIMIZING THE IMPACT OF URBANIZATION ON LONG TERM RUNOFF1

Increasing concern about the problems caused by urban sprawl has encouraged development and implementation of smart growth approaches to land use management. One of the goals of smart growth is water resources protection, in particular minimizing the runoff impact of urbanization. To investigate the magnitude of the potential benefits of land use planning for water resources protection, possible runoff impacts of historical and projected urbanization were estimated for two watersheds in Indiana and Michigan using a long term hydrological impact analysis model. An optimization component allowed selection of land use change placements that minimize runoff increase. Optimizing land use change placement would have reduced runoff increase by as much as 4.9 percent from 1973 to 1997 in the Indiana study watershed. For nonsprawl and sprawl scenarios in the Michigan watershed for 1978 to 2040, optimizing land use change placement would have reduced runoff increase by 12.3 percent and 20.5 percent, respectively. The work presented here illustrates both an approach to assessing the magnitude of the impact of smart growth and the significant potential scale of smart growth in moderating runoff changes that result from urbanization. The results of this study have significant implications for urban planning.     

体育场雨水回用可行性初探

以杭州某体育场为例,分析该体育场收集屋面和路面雨水作为体育场绿化、田径场喷灌、跑道浇洒等水源的可行性,结果表明该体育场通过雨水回用达到绿色建筑节水率要求,并提高大型体育场水循环利用率、实现水资源的可持续利用。     

三峡库区典型退耕还林模式土壤养分流失控制

选择三峡库区典型退耕还林模式,包括园地(茶园)及林地(板栗)与原有坡耕地对照,观测并分析其土壤养分(氮磷)输出途径及数量情况,以评估实施退耕还林工程对流域土壤养分输出的影响.结果表明:1退耕后土壤养分氮磷年流失量(包括随泥沙和地表径流流失的量)减少;总氮(TN)年输出量从大到小依次为坡耕地(2 444.27 g·hm-2)茶园地(998.70g·hm-2)板栗林地(532.61 g·hm-2);总磷(TP)为坡耕地(1 690.48 g·hm-2)茶园地(488.06 g·hm-2)板栗林地(129.00 g·hm-2);与坡耕地比较,退耕还林模式(园地、林地)总氮、总磷年输出载荷分别减少了68.68%和81.75%.2茶园地、板栗林地与坡耕地相比,土壤养分速效态氮流失量明显减少,硝态氮(NO-3-N)输出总量依次为坡耕地(113.79g·hm-2)茶园地(73.75 g·hm-2)板栗林地(56.06 g·hm-2);铵态氮(NH+4-N)养分输出次序为茶园最大(69.34 g·hm-2),坡耕地次之(52.45 g·hm-2),板栗林地最小(47.23 g·hm-2).3硝态氮、铵态氮主要通过地表径流输出,所占总量比例分别为91.4%和92.2%;总氮和总磷主要通过泥沙输出,所占总量比例分别为86.6%和98.4%.通过退耕还林等措施,该地区地表径流以及土壤侵蚀输出明显减少,土壤养分流失得到有效控制.