Soil erosion and risk-assessment for on- and off-farm impacts: A test case using the Midhurst area,West Sussex,UK

Soil erosion on agricultural land is a growing problem in Western Europe and constitutes a threat to soil quality and to the ability of soils to provide environmental services. The off-site impacts of runoff and eroded soil, principally eutrophication of water bodies, sedimentation of gravel-bedded rivers, loss of reservoir capacity, muddy flooding of roads and communities, are increasingly recognised and costed. The shift of funding in the European Union (EU) from production-related to avoidance of pollution and landscape protection, raises issues of cross-compliance: public support for agriculture has to be seen to give value-for-money. In this context risk-assessment procedures have been introduced to help farmers recognise sites where either certain crops should not be grown or anti-erosion measures are required. In England, Defra [Defra, 2005a. Controlling Soil Erosion: a Manual for the Assessment and Management of Agricultural Land at Risk of Water Erosion in Lowland England. Revised September 2005. Department for Environment, Food and Rural Affairs, London] sets out a system of risk-assessment, including ranking of crops susceptible to erosion and anti-erosion measures, that may be selected. We assess this system using field data for an area of erodible soils in the Rother valley, Sussex. The Defra approach correctly identifies most at-risk fields and, taken together with land-use maps, allows non-compliance with advice to be highlighted. We suggest a simple extension to the system which would further identify at-risk fields in terms of possible damage to roads and rivers from muddy runoff. The increased risk of erosion in the study area is associated with certain crops: potatoes, winter cereals, maize and grazed turnips and seems unlikely to be the result of changes in rainfall which over the last 130 years are minimal. We have not evaluated proposed anti-erosion measures in the area because few have been put into practice. The European Water Framework Directive will increasingly focus attention on agricultural fields as a source of river pollution. Assessing the risk of erosion and the need for field testing of suggested approaches, are not simply issues for the EU, but for the management of global agricultural systems.     

The Influence of the Pacific Decadal Oscillation on Annual Floods in the Rivers of Western Canada

We analyzed annual peak flow series from 127 naturally flowing or naturalized streamflow gauges across western Canada to examine the impact of the Pacific Decadal Oscillation (PDO) on annual flood risk, which has been previously unexamined in detail. Using Spearman's rank correlation ρ and permutation tests on quantile‐quantile plots, we show that higher magnitude floods are more likely during the negative phase of the PDO than during the positive phase (shown at 38% of the stations by Spearman's rank correlations and at 51% of the stations according to the permutation tests). Flood frequency analysis (FFA) stratified according to PDO phase suggests that higher magnitude floods may also occur more frequently during the negative PDO phase than during the positive phase. Our results hold throughout much of this region, with the upper Fraser River Basin, the Columbia River Basin, and the North Saskatchewan River Basin particularly subject to this effect. Our results add to other researchers' work questioning the wholesale validity of the key assumption in FFA that the annual peak flow series at a site is independently and identically distributed. Hence, knowledge of large‐scale climate state should be considered prior to the design and construction of infrastructure.     

Comparison of membrane fouling during short-term filtration of aerobic granular sludge and activated sludge

Aerobic granular sludge was cultivated adopting internal-circulate sequencing batch airlift reactor.The contradistinctive experiment about short-term membrane fouling between aerobic granular sludge system and activated sludge system were investigated.The membrane foulants was also characterized by Fourier transform infrared(FTIR)spectroscopy technique.The results showed that the aerobic granular sludge had excellent denitrification ability;the removal efficiency of TN could reach 90%.The aerobic granular sludge could alleviate membrane fouling effectively.The steady membrane flux of aerobic granular sludge was twice as much as that of activated sludge system.In addition,it was found that the aerobic granular sludge could result in severe membrane pore-blocking, however,the activated sludge could cause severe cake fouling.The major components of the foulants were identified as comprising of proteins and polysaccharide materials.     

Multi-biological defects caused by lead exposure exhibit transferable properties from exposed parents to their progeny in Caenorhabditis elegans

Whether the multi-biological toxicity from lead exposure could be transferred to progeny has not been clarified.In the present study,we explored the Caenorhabditis elegans to analyze the multiple toxicities from lead exposure and their possibly transferable properties.The lead exposure could cause series of severe multi-biological defects with a concentration-dependent manner by affecting the endpoints of life span,development,reproduction and locomotion behaviors in nematodes.Moreover,most of these toxicities could be transferred to progeny from lead exposed animals and some of the defects in progeny appeared even more severe than in their parents,such as the body sizes and mean life spans.We summarized the defects caused by lead exposure into three groups according to their transferable properties or rescue patterns.That is,the defects caused by lead exposure could be largely,or partially,or became even more severe in progeny animals.Therefore,our results suggest that lead exposure can cause severely multi-biological defects,and most of these multiple toxicities can be considered as transferable for exposed animals in C.elegans.     

采用保护性耕作对减少水稻产量损失的实证分析——基于4省1080个稻农的调研数据

干旱和洪涝是造成水稻减产最主要的自然灾害,稻农通过采用保护性耕作可以减少其对水稻的产量损失。基于2013—2015年中国水稻主产区1 080个水稻农户的调研面板数据,论文采用内生转换模型,实证分析了稻农通过采用保护性耕作应对干旱或洪涝的效果,并分别估计了采用者和未采用者的水稻单产情况。实证结果表明:1)采用者的水稻单产远远高于未采用者的水稻单产;2)在反事实假设情况下,如果采用者未采用保护性耕作,其水稻产量将相应减产457.95 kg/hm~2(约7%);如果未采用者采用保护性耕作,其水稻产量将相应增产225 kg/hm~2(约4%);3)户主种植经验、受教育年限和公共服务可得性正向影响稻农的采用行为。最后,论文建议政府应大力推广保护性耕作技术,加大对抗逆水稻品种的培育,加强对农业生产资料的投入和管理,扩大公共服务的覆盖范围。     

重污染河道中浮游植物初级生产力特征

通过对苏州城市河道的调查研究发现,城市河道的浮游植物初级生产力与其它水体有明显不同。从2004年6月至2005年5月通过取样分析苏州苗家河水体浮游植物种类、数量和叶绿素a含量变化及采用黑白瓶法测定浮游植物产氧能力,结果表明:该河道氮、磷含量较高,浮游植物群落为绿藻-硅藻型,种类少,季节变化明显,水体中表层叶绿素a的含量低于底层。分析表层水体和底层水体叶绿素a的产氧能力发现,河道中浮游植物的光合产氧能力普遍较低。本文揭示了重污染河道中大量悬浮颗粒附着在浮游植物的体表,影响了浮游植物的光合产氧能力,是整个水体和底泥中的溶氧普遍较低的重要原因之一。探讨了重污染河道溶氧偏低产生黑臭的原因,为重污染河道的综合治理提供了参考。     

Major shifts in Amazon wildlife populations from recent intensification of floods and drought

In the western Amazon Basin, recent intensification of river‐level cycles has increased flooding during the wet seasons and decreased precipitation during the dry season. Greater than normal floods occurred in 2009 and in all years from 2011 to 2015 during high‐water seasons, and a drought occurred during the 2010 low‐water season. During these years, we surveyed populations of terrestrial, arboreal, and aquatic wildlife in a seasonally flooded Amazonian forest in the Loreto region of Peru (99,780 km²) to study the effects of intensification of natural climatic fluctuations on wildlife populations and in turn effects on resource use by local people. Shifts in fish and terrestrial mammal populations occurred during consecutive years of high floods and the drought of 2010. As floods intensified, terrestrial mammal populations decreased by 95%. Fish, waterfowl, and otter (Pteronura brasiliensis) abundances increased during years of intensive floods, whereas river dolphin and caiman populations had stable abundances. Arboreal species, including, macaws, game birds, primates, felids, and other arboreal mammals had stable populations and were not affected directly by high floods. The drought of 2010 had the opposite effect: fish, waterfowl, and dolphin populations decreased, and populations of terrestrial and arboreal species remained stable. Ungulates and large rodents are important sources of food and income for local people, and large declines in these animals has shifted resource use of people living in the flooded forests away from hunting to a greater reliance on fish.     

Investigation on the role of traffic volume in accidents on urban highways

Introduction

Roadway safety is a major concern for the general public and public agencies, as roadway crashes claim many lives and cause substantial economic loss each year. In Iran, a large number of vehicles are involved in road accidents each year, which cause many deaths and extensive property damage; such accidents are among the major causes of death and disability in the country. Method: To reduce roadway accidents, the factors that affect the occurrence and severity of accidents should be scrutinized to prevent or reduce their effect. The method that many researchers have adopted to determine the effective parameters surrounding road accidents in recent years is through statistical modeling of accidents. In this article, the role of different kinds of vehicles in traffic flow are investigated separately in terms of the likelihood of crashes on urban highways, and the vehicles are divided into three groups: passenger cars, heavy vehicles, and light non-passenger car vehicles. Poisson and negative binomial (NB) regression models were applied to model the accidents in this research, which were categorized into two groups: no injury (property damage only) accidents and more severe (injury and fatal) accidents. Results: Ultimately, we conclude that light non-passenger car vehicles (i.e., taxis and motorcycles) play the largest role in the occurrence of crashes on urban highways for both types of accidents.     

2013~2021年邢台PM2.5重污染过程输送和增长特性

利用河北邢台2013~2021年的PM_2.5、气象要素和模拟资料,着重针对重度及以上污染过程（SAAP）中PM_2.5增长速率、来源及其与大气环流和风场的关联性进行分析.结果表明,2013~2021年邢台共发生PM_2.5污染过程164次,SAAP 103次.地面环流中倒槽型出现概率较低,但出现污染概率最高（61.1%）,其次为高压控制型;500 hPa为平直西风带控制时重度及以上污染概率最高（20.7%）,槽后型次之（16.1%）.SAAP中PM_2.5小时变化率（ΔPM_2.5）主要在±150 μg ·（m³ ·h）^-1,PM_2.5小时变化率为正（+ΔPM_2.5）贡献约61.7%,其中暴发增长占比约13.9%.北偏东风为与重度及以上污染关联最为紧密的风向.中等风速条件下SAAP中ΔPM_2.5平均值大多低于静小风,但东偏北和南偏西部分风向区间中,中等风速ΔPM_2.5平均值显著高于静小风（与污染传输有关）;较大风速对ΔPM_2.5影响复杂.后向轨迹表明,SAAP中缓慢、快速和暴发增长的后向轨迹可分为北偏西、北偏东和偏南3个主要路径,随增长速度加快,北偏西气团来向占比增大.缓慢增长气团相对湿度（RH）较大（80%以上RH>50%）,快速增长气团RH分布较集中（主要为35%~55%）,暴发增长中的低RH （RH<50%）气团占比明显增加（约63%）.模拟表明SAAP可分为本地累积、北部偏东输送、北部偏西输送、混合输送型和偏南输送这5类,其中混合输送型占比最高,其次为北部偏西输送型.偏南输送、本地累积和北部偏东输送型中出现概率最高的高低空配置均为高空槽后配合地面均压场;北部偏西输送型中地面高压配合高空槽后出现概率最高;混合输送中多种环流配比相对均衡.     

1960～2012年中国东南沿海地区降水变化特征及重涝灾害趋势判断

基于东南沿海地区46个气象站点逐年实测降水数据,采用线性回归、Mann-Kendall检验法、Z指数法等气候诊断方法分析了1960~2012年东南沿海降水量时空变化特征,利用可公度、蝴蝶结构图和可公度结构系等灾害时间对称性方法,对重涝灾害未来趋势进行判断。结果表明:1)1960~2012年东南沿海地区降水整体呈增加趋势,增加速率为1.91mm/a;2)在空间变化上,降水量高值区域,降水呈现下降趋势,而降水量低值区域,降水则呈现上升趋势;降水呈下降趋势的区域集中在降水高值区,由南向北降水呈下降趋势站点逐渐减少,区域洪涝灾害风险逐渐增大;3)东南沿海旱涝变化具有明显的年际变化趋势,主要表现为20世纪60~70年代整体偏旱,80~90年代涝灾逐年增多,2000年后旱涝灾害频发,形成"重旱-重涝并重"的格局;4)东南沿海地区重涝时间序列具有明显的时间对称结构,经可公度、蝴蝶结构图和可公度结构系三种方法综合判断,2016年重涝信号较强,有可能发生较严重的涝灾,需要相关部门予以重视,完善区域自然灾害防御应急体系。