汾河下游丰水和枯水期的河流硝酸盐污染来源特征

[目的]对汾河径流丰水期和枯水期的河流硝酸盐污染来源特征进行对比分析和研究,为汾河下游氮源污染治理提供理论支持。[方法]通过研究2018年汾河下游水体硝酸盐及其氮、氧同位素不同时期的变化,分析排入河流的硝酸盐来源雨期性变化特征,并引入IsoSoure模型,定量计算各污染源对汾河下游水体硝酸盐的贡献。[结果]在丰水期和枯水期,δ~(15)N值变化范围为3.45‰～11.19‰,δ~(18)O值变化范围为-0.72‰～3.17‰,硝酸盐污染源主要为农业化肥、土壤有机氮、生活污水与粪便;硝酸盐污染源主要与汾河下游周围土地利用类型相关,丰水期临汾段与M_5采样点硝酸盐污染源主要为粪便和污水,分别占比为58%,40%,72%和58%,M_6—M_9段农业化肥贡献率最高,占比分别45.4%,62%,56.6%,56.5%。枯水期所有采样点硝酸盐污染源贡献率最高的都为粪便和污水,占比为40%～73%。[结论]汾河径流硝酸盐污染来源主要为农业化肥、土壤有机氮、生活污水与粪便,并且污染来源与土地利用类型有很强相关性,不同水期硝酸盐污染来源大多为粪便和生活污水,差别主要体现在M_6—M_9取样点,丰水期主要污染物为农业化肥,而枯水期为粪便与生活污水。     

6种水生植物及其组合对模拟污水中磷的净化效果

[目的]针对河流湖泊水体污染严重现状,选择6种水生植物进行水质净化试验,为污染水体的水生植物治理提供选择依据。[方法]选择6种具观赏效果的水生植物菖蒲、美人蕉、大薸、凤眼莲、金鱼藻、穗花狐尾藻,采用静态水培的方法,研究6种水生植物及其组合对不同浓度模拟污水中总磷净化效果。[结果]单一水生植物试验中,凤眼莲在高(2 mg/L)、中浓度(0.5 mg/L)磷水体中总磷去除效果最好,去除率分别为95.9%,93.4%。金鱼藻在低浓度磷(0.1 mg/L)水体中总磷去除效果最好,去除率为91.1%。组合水生植物试验中,高浓度磷水体中金鱼藻+菖蒲+凤眼莲的水生植物组合对水体中总磷去除效果最好,去除率为96%。中浓度磷水体中穗花狐尾藻+菖蒲+凤眼莲水生植物组合总磷去除效果最好,去除率为98.8%。低浓度磷水体中穗花狐尾藻+菖蒲+大薸水生植物组合总磷去除效果最好,去除率为94.3%。[结论]选择的6种水生植物对总磷均有一定的去除效果,对水生植物的种植数量、面积、时间以及组合方式进行优化配置,可用于污染水体水质净化。     

山东武河人工湿地对磷净化的长效性及其内源磷分布与释放

人工湿地运行的长效性值得关注,以山东省武河人工湿地为例,2017年10月选取10个和4个代表性采样点分别采集原位水样和柱状沉积物样,对该湿地正常运行10年后,其对水体磷的净化效果和沉积物磷的分布特征及其内源释放风险进行了研究。结果表明:武河人工湿地运行10年后,对水体磷仍具有较好的净化效果,净化效率在50%左右,出水口总磷(TP)浓度为0.29 mg L^-1,符合地表水Ⅳ类水质标准。4个沉积物柱样均显示,沉积物各磷形态含量大小顺序为:无机磷(IP)>钙磷(Ca-P)>铁铝结合态磷(Fe/(Al-P)>不稳定态磷(LP)>有机磷(OP),IP含量最高,约占总磷的69%~95%,OP含量极低,与湿地来水息息相关;在IP中,沉积物Ca-P含量最高,表现为较为稳定的特性;空间分布上,不同点位各磷形态含量差异显著,进水口较近区域含量较高,垂向上,除Ca-P外,其他磷形态含量总体呈现随深度增加而减少的趋势,湿地来水影响明显。静态释放实验表明,湿地不同点位沉积物磷的内源释放速率差异明显,4个点位总磷的沉积物-水界面释放速率分别为-1.98、-9.32、-11.99和-8.65 mg m^-2 d^-1,均以吸附为主,距离进水口较近区域,沉积物对磷的吸附能力有所降低,这对人工湿地的长期运行具有指导意义。相关性分析表明,除Ca-P外,沉积物其他磷形态同有机质(LOI)表现出较好相关性,沉积物磷形态和LOI来源相对一致,主要为临沂城区工业废水和生活污水的尾水,受农业面源污染的影响较小。     

不同类型岩溶湿地表层沉积物碳氮磷生态化学计量学特征时空分布

为了厘清湿地生态系统碳汇潜力和生态系统对环境变化的响应。以滇东南典型岩溶流域普者黑为研究对象,将岩溶湿地划分为河流湿地、湖泊湿地、沼泽湿地和库塘湿地4种类型,研究湿地沉积物碳、氮和磷的平衡关系,探讨了丰水期、枯水期和平水期不同水期湿地表层沉积物碳、氮、磷的分布及生态化学计量学特征。结果表明:(1)普者黑流域不同类型湿地表层沉积物SOC,TN-S,TP-S含量在不同时期的变化规律不一致,SOC含量在平水期的库塘湿地最高,为47.81 g/kg,丰水期的沼泽湿地最低,为12.77 g/kg;TN-S含量在枯水期的沼泽湿地最高,为2.93 g/kg,丰水期的库塘湿地最低,为1.22 g/kg;TP-S含量在河流湿地最高,为1.32 g/kg,丰水期的沼泽湿地最低,分别为0.43 g/kg;且不同类型湿地表层沉积物SOC,TN-S,TP-S之间呈显著正相关(p0.05);(2)不同类型湿地表层沉积物C/N-S,C/P-S和N/P-S在不同时期下的变化规律基本一致,从枯水期、丰水期至平水期除湖泊湿地外均呈上升趋势,C/N-S和C/P-S在平水期的库塘湿地最高,分别为25.43,94.49,N/P-S在平水期的沼泽湿地最高,为4.04;C/N-S,C/P-S和N/P-S在枯水期的河流湿地最低,分别为9.17,14.85,1.62,且不同类型湿地表层沉积物C/N-S,C/P-S,N/P-S与TN-S,TP-S及水质N/P-W之间呈显著正相关(p0.05);(3)总体上看,丰水期的SOC,TN-S,TP-S含量均低于枯水期和平水期,平水期的C/N-S,C/P-S和N/P-S值均高于枯水期。     

亚热带典型农林混合流域河岸带景观格局对河流磷输出的影响

为进一步明确流域河岸带景观尺度范围差异性及对河流磷(P)输出的影响,量化解析河岸带尺度下景观与河流P之间的关系。以亚热带典型农林混合流域为研究对象,基于长期水文、水质监测数据,利用冗余分析明确不同河岸带尺度景观格局特征与不同水文季节河流P浓度的关系,并采用变点分析量化导致丰水期、平枯水期河流P浓度突变的核心景观指数的阈值范围。结果表明:(1)河岸带景观格局对河流P浓度的影响具有显著的空间尺度性特征,300,400 m分别是影响丰水期和平枯水期河流磷浓度变化的关键临界尺度。(2)河岸带居民地斑块最大斑块面积指数(LPI_居)和农田斑块分散指数(SPLIT_农)分别是影响平枯水期和丰水期河流磷浓度的核心景观格局特征指数,当SPLIT_农＞15.76~23.83,LPI_居＜28.8%~36.5%时,能够降低河流P浓度的突变概率。研究结果可为以缓解P面源污染为目标的土地利用和景观规划提供重要理论依据。     

苏州市环太湖农业面源污染调查及控制对策

在跟踪监测东太湖水环境质量基础上,对苏州环太湖15个乡镇或街道农业面源污染源进行面上调查和实地调查,综合国内外尤其是太湖地区研究成果,进行农业面源污染评价与分析。结果表明:东太湖水域TN、TP、CODMn和Chl-a的平均值分别为0.817mg·L-1、0.074mg·L-1、4.054mg·L-1和0.0176mg·L-1,属轻度富营养化湖泊,其中,TP可能是蓝藻爆发的限制因子;各类污染源对苏州环太湖农业面源污染贡献大小依次为:生活污水>种植业>水产养殖业>畜禽养殖业。本研究提出了苏州环太湖农业面源污染的控制对策,为实现我国制定的2010年太湖达中等营养水平及主要出入湖河流达到GB3838—88中Ⅱ类水质的保护目标提供基本思路。     

德州地区地下水中磷的空间分布特征及来源分析

地下水质量与居民饮水安全及人类健康密切相关,地下水污染会直接影响水体生态环境。饮用水中过高的磷会降低人体对钙和维生素D的吸收,对老年人的身体健康存在潜在负面影响。本文以德州地区地下水(常作为农村饮用水源)为研究对象,采集了研究区内的27个地下水样,并于现场测定pH和电导率等指标。参考我国《水和废水监测分析方法》和美国环境保护局(EPA)的方法,利用紫外分光光度计分析了地下水中总磷、正磷酸盐、溶解性总磷和溶解性正磷酸盐的含量及污染状况。借助于空间分析,探讨了其空间分布和来源。结果表明,德州地区地下水总磷含量为0~1.49 mg.L 1,正磷酸盐含量为0~0.11 mg.L 1,溶解性总磷含量为0.04~0.69 mg.L 1,溶解性正磷酸盐含量为0~0.06 mg.L 1。电导率和4种形态磷的含量均存在不同的空间差异性。整个研究区地下水电导率较高,变化范围为770~5 530μS.cm 1,总体上从河流上游到下游呈明显阶梯状递增趋势;总磷和溶解性总磷含量的空间分布整体趋势从上游到下游逐渐降低,正磷酸盐出现了较明显的高值区,而溶解性正磷酸盐的空间分布整体上较均匀。影响地下水中磷含量的因素主要有地表水中磷的下渗和人类活动。该研究区各采样点地下水的埋深都在50 m以内,含水层为黄河冲积砂层,岩性主要为粉砂、细砂和中砂,累计厚度10~25 m,这样的土壤地质构造较易使地表水中的磷素渗漏到地下水中,且河流是该区地下水主要的补给源,越靠近河流越容易入渗。人类活动包括工业废水和生活污水处理不当等点源污染以及农药施肥等农业非点源污染。整个研究区地下水溶解性总磷含量的最大值达0.69 mg.L 1,平均值为0.20 mg.L 1,根据欧盟规定的饮用水中总磷酸盐的标准值(0.5 mg.L 1)和我国地表水环境质量标准(GB 3838—2002)的Ⅱ类(0.02<溶解性总磷≤0.1 mg.L 1)或Ⅲ类(0.1<溶解性总磷≤0.2 mg.L 1)标准,德州地区地下水中磷的超标率分别达7.41%、62.96%和40.74%。本研究为评价地下水中磷污染对人类健康及水体生态环境的影响提供了科学依据。     

稻田化肥减量施用的环境效应

在太湖地区宜兴市水稻田采取田间试验与室内分析相结合的方法,研究了适当减少化肥用量(优化施肥)对水稻产量、田面水与渗漏液中氮、磷养分的影响.结果表明:优化与常规两种施肥处理下水稻产量差异不显著,但优化施肥节省22%氮肥,减少30%～40%氮素径流损失,减少32.3%氮素渗漏损失.田面水与渗漏液中溶解性总氮(TDN)浓度与施肥量呈正相关,在施肥后的1～2 d内达到峰值,不同施氮处理TDN浓度在一周内差异显著,以后渐趋一致.施肥后田面水中溶解性总磷(TDP)浓度高达15.7 mg·L-1,整个稻季均高于导致水体富营养化的临界值,存在着污染附近水体的风险;稻田对灌水中的磷有净化作用.适当减少化肥用量、加强稻田水肥管理,是控制农田面源污染的重要措施.     

基于梯度扩散薄膜技术的太湖金属和营养盐区域污染特征分析

本研究利用梯度扩散薄膜技术（Diffusive gradients in thin-films,DGT）对太湖7个湖区的水体和沉积物中金属与营养盐有效态含量进行原位监测,并分析污染物的区域特征。结果表明,DGT所测有效态浓度低于传统化学方法所提取浓度,且能实现低浓度、多元素同时监测。具体来看,太湖水体中金属的DGT有效态含量较低,区域差别较小。沉积物中9种典型金属的DGT有效态含量排序为Fe>Mn>Zn>Ni>As>W>Co>Mo>Cu,其中,Fe、As、Zn、Ni和W在竺山湾、梅梁湾和贡湖污染相对较重,在湖心区、胥湖和东太湖污染相对较轻,其余金属分布较平均且含量较低。与金属不同的是,太湖水体中DGT所测的有效磷（P）含量整体较高,最高值出现在贡湖,达83.2μg·L-1。沉积物中DGT有效态P的区域分布更明显,以竺山湾、梅梁湾和沿岸区污染相对较重,最高值出现在竺山湾,达500μg·L-1。对比沉积物和水体中DGT有效态P含量发现,竺山湾、梅梁湾和沿岸区沉积物可能是P的主要储存场所,具有潜在释放风险。     

外源磷输入对农区湿地土壤碳库有效性及周转特性的影响

通过添加土壤原总磷(TP)0~60%的过磷酸钙和室内培养的技术手段,研究了外源磷素输入对农区湿地土壤碳库有效性及其周转特性的动态影响。结果表明,随外源磷素输入水平的增加,土壤可溶性有机碳(DOC)含量和微生物量碳(MBC)含量增加;土壤总有机碳(TOC)含量下降,下降率最高达23%。活性有机碳成分中,外源磷输入对高活性有机碳(HLOC)影响最显著,60%磷素输入处理HLOC含量比未施加外源磷素高54%;易氧化有机碳(ROC)含量随外源磷输入水平的增加而下降,最大下降率为22%;中活性有机碳(MLOC)含量、活性有机碳(LOC)含量无明显改变。涉碳循环生物酶中,β-葡聚糖苷酶(βG)和纤维二糖水解酶(CBH)活性均随外源磷素输入水平的增加而显著提升,但脱氢酶(DH)活性并无显著变化。此外,土壤碳矿化强度和潜在矿化势也与外源磷素输入后的土壤TP呈正相关。总体来看,外源磷素输入显著增加了湿地土壤碳库的有效性及周转速率。     

Impacts of Molybdate Unreactive Phosphorus on Phosphate Release from Intensively Fertilized Soil

Total phosphorus (P) in soil is classified as molybdate-reactive P (MRP) and molybdate-unreactive P (MUP) based on bioavailability, and P tests are generally focused on MRP fraction of soil, despite the fact that MUP can contribute significantly to total extracted P. This survey study indicated that water-soluble P (WP) contributed as much as 9% to total P (TP) in two intensively fertilized (rice–onion cropping upland and greenhouse) soils, and most (ca. 80%) of WP was present in MUP form. The total P lost through runoff and leaching was high (>5 ppm), due to rotating greenhouse into submerged paddy soil, especially at the initial stage of rice cultivation, and MUP contributed 43% and 77% to total P lost through runoff and leaching, respectively. Therefore, it is necessary to monitor MUP to develop suitable soil-management strategies to reduce MUP release and P loss from high-P-containing soils.     

Adapting and evaluating APSIM-SoilP-Wheat model for response to phosphorus under rainfed conditions of Pakistan

Phosphorus (P) treatments were used to evaluate APSIM-SoilP-Wheat model and phosphorus use efficiency (PUE) of two wheat cultivars (NARC-2009 and Chakwal-50) during 2011–2013. Overall, the Agricultural Production Systems Simulator (APSIM) model accurately simulated dry matter, grains per spike, grain yield, biomass P, and grain P for two years, for both genotypes in response to all P fertilizer treatments. NARC-2009 had 55% higher PUE compared to Chakwal-50. Information on PUE will be helpful in breeding high PUE cultivars. Modeling results showed that the production of wheat depends on growth as well as on P uptake of the plants. The close agreement between observed and simulated results confirmed the accuracy of the model which was validated with skill scores like R² and RMSE. APSIM simulation proved to be valuable tool to evaluate PUE under rainfed conditions.     

3种典型河岸林土壤氮磷的空间分布格局及其影响因素

通过等距离梯度密集采样,结合主成分分析和相关性分析,研究了3种河岸林土壤全氮和全磷的空间分布及其影响因素。结果表明,3种河岸林全氮储量表层显著高于中层和底层;全磷储量层次性不明显。3种河岸林中,云杉河岸林土壤的氮磷储量最大,青杨辽东栎混交林次之,落叶松辽东栎最小。影响全氮分布的主要因子为有机质和植被盖度;影响全磷分布的主要因素为土层厚度和土壤容重。     

32P distribution in white radish roots at various fertilization rates

Abstract

The uptake and distribution of ³²P from labelled monocalcium phosphate by white radish (Raphanus Sativus) roots at five phosphorus fertilization rates were studied.

After on initial period of degradation (approximately 6 weeks), there is a sharp decline of phosphorus uptake. Graphical representation in Tables and Figures of the phosphorus distribution is presented.     

水库淹没土壤中磷浸出的模拟实验研究

水库建成蓄水后,库底土壤中磷的浸出会对库水水质产生一定影响。以南水北调中线工程的调蓄水库——瀑河水库为例,在现场调查基础上,使用蒸馏水和不同组分的3种模拟水分别进行模拟实验,考察库水中总磷与钙离子浓度对土壤中磷浸出的影响。实验结果表明,蒸馏水与模拟水中总磷浓度均发生一定程度的变化,模拟水中的浓度变化比蒸馏水中的变化复杂;模拟水中总磷或钙离子浓度较高时,土壤中磷的浸出量较少,对库水水质未产生明显不良影响。     

Effects of Rice Husk Ash and Bagasse Ash on Phosphorus Adsorption and Desorption in an Alkaline Soil under Wheat–Rice System

Rice husk ash (RHA) and bagasse ash (BA) are available in large quantities in South Asian countries growing rice and sugarcane. Land application of RHA and BA is likely to influence chemistry of soil phosphorus (P) and thereby P adsorption and desorption. Laboratory studies were carried out to investigate the short-term and long-term effects of RHA and BA application on P adsorption and desorption in an alkaline soil under a wheat–rice system. Addition of RHA or BA (10 Mg ha^?1) resulted in a significant decrease in P adsorption compared to the control. The decrease in P adsorption was lower when RHA and BA were applied to either rice or wheat as compared with when applied to both the crops. The BA was more effective in reducing P adsorption than RHA because of its greater P concentration. Fresh addition of RHA and BA at 1% (dry-weight basis) showed a small effect on P adsorption as compared to their long-term application. The Frendulich isotherm equation gave better fit with the experimental data than the Langmuir equation and is reliable to describe the P quantity/intensity relationships of this soil as affected by the additions of RHA and BA. The P-adsorption capacities (revealed from the Langmuir isotherms) of the unamended control, RHA, and BA (applied to both wheat and rice) were 256, 313, and 385 mg kg^?1, respectively; the corresponding bonding energies for the three treatments are 0.0085, 0.0041, and 0.0026 L kg^?1, respectively. Desorption of P was minimum in the control plots and maximum with BA followed by RHA, especially when applied to both the crops.     

外源磷与AMF对间作玉米种植红壤无机磷形态的影响

通过三室隔网分室盆栽模拟试验,研究了分室不同磷(P)源[无机磷(磷酸二氢钾)和有机磷(大豆卵磷脂),P添加量均为50 mg·kg-1]添加和根室接种不同丛枝菌根真菌(AMF)[Glomus mosseae(GM)、Glomus etunicatum(GE)]对间作玉米种植红壤无机磷形态的影响。结果表明:无论接种与否,间作处理使根室土壤有效磷含量显著降低,说明间作能够促进玉米植株对土壤有效磷的吸收,且有效磷的耗竭从根际土壤开始。除OP50-单作玉米处理的Org-P外,接种AMF均一定程度增加了各形态无机磷含量。此外,根室土壤有效磷的主要组分为Ca2-P、Al-P和Org-P,其中Org-P与土壤有效磷有着极显著的负相关关系。     

Arbuscular Mycorrhizal Fungi Enhance Tolerance of Rosa multiflora cv. Burr to Bicarbonate in Irrigation Water

ABSTRACT

High bicarbonate (HCO₃ ^?) of irrigation water can be detrimental to plant growth in sustainable horticultural production systems. The ability of arbuscular mycorrhizal fungi (AMF), ZAC-19, (composed of Glomus albidum, Glomus claroideum, and Glomus diaphanum) to enhance tolerance to HCO₃ ^? was tested on Rosa multiflora cv. Burr. Arbuscular mycorrhizal colonized and non-inoculated (non-AMF) plants were treated with 0, 2.5, 5, and 10 mM HCO₃ ^?. Increasing HCO₃ ^? concentration and associated high pH and electrical conductivity (EC)—reduced plant growth, nutrient uptake, and acid phosphatase activity, while increasing alkaline phosphatase activity (ALP). Inoculation with AMF enhanced plant tolerance to HCO₃ ^?, as indicated by greater growth (leaf, stem, and total plant dry weight, leaf area and leaf area ratio), leaf elemental concentration [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), iron (Fe), zinc (Zn), aluminum (Al), boron (B)], leaf chlorophyll concentration, higher mycorrhizal inoculation effect, lower root Fe reductase activity, and generally lower soluble ALP activity. While AMF colonization was reduced by increasing HCO₃ ^? concentration, colonization still occurred at high HCO₃ ^? concentration. At 2.5 mM HCO₃ ^?, AMF plant growth was comparable to plants at 0 mM HCO₃ ^?, further indicating the beneficial effect of AMF for alleviation of HCO₃ ^? plant stress.     

Simple filtration system improves efficiency of a hydropneumatic root elutriator

Abstract

Separating roots from soil is a laborious and costly process, but a commercially available hydropneumatic root elutriator can semi‐automate the job. Hydraulic and pneumatic systems elutriate the roots from the soil, while the electrical system controls the on/off functions of the hydraulic system. The extruded steel frame of the elutriator serves a dual purpose; structural support and transport of water and compressed air. Water is transported in the lower and air in the upper part of the hollow inner cavity of the extruded steel frame. They exit the frame into polyethylene tubes that extend to the base of the elutriator. After prolonged use, however, this design feature can become problematic because flow to the elutriator of either system can be blocked at the nozzle inlets with rust particles that originate from the steel frame's inner walls. The blockage increases sample processing time due to dismantling, clearing, and reassembling, which eventually degrades the elutriator. To resolve these problems a 40‐mesh (420 micron) in‐line stainless steel water filter and a 40‐micron in‐line bronze air filter were installed in the polyethylene tube lines between the extruded steel frame and the base of the elutriator. These filters were found to reduce nozzle blockage, thereby increasing sample processing efficiency by 10% and improving sample quality.     

土壤磷素淋溶预测指标研究

对西北农林科技大学农作一站长期肥料试验地0—20 cm耕层土壤研究表明:(1)易释放的各形态磷与全磷呈正相关关系;(2)土壤磷素的释放能力随pH值的增大而减小,不同处理的缓冲能力不同。释放能力的大小也与全磷的多少有关;(3)土壤全磷与PSD(土壤磷饱和度)有很好的正相关性。因此,基于以土壤饱和度为25%作为预测指标,把土壤全磷环境敏感指标(TP)为1.92 g/kg作为关中磷淋溶的环境敏感指标。