The effect of total carbon on microscopic soil properties and implications for crop production

Soil structure is a dynamic property affected by physical, chemical, and microbiological processes. Addition of organic matter to soils and the use of different management practices have been reported to impact soil structure and crop production. Moderation in soil temperature and increases in microbial activity and soil water retention are often suggested as reasons for the rise in crop yield when organic matter is added to the soil. Less is known about the direct effect of changes in soil structure on crop production. A field experiment was conducted to study the effect of summer cover crop and in-season management system on soil structure. The experiment was a nested design with summer cover crop as the main plot and management system as the subplot. Summer cover crop treatments included cowpea （Vigna unguiculata L. Walp.） incorporated into the soil in the fall （CI）, cowpea used as mulch in the fall （CM）, sudangrass （Sorghum vulgare） incorporated into the soil in the fall （S）, and dry fallow or bare ground （B）. Management systems were organic （ORG） and conventional （CNV） systems. Lettuce （Lactuca sativa L.） and cantaloupes （Cucumis melo L.） were cultivated in rotation in the plots for three consecutive years using the same cover crops and management systems for each plot. Disturbed and undisturbed soil cores were collected at the end of the third year and used for laboratory experiments to measure physical, chemical, and hy- draulic properties. Image analysis was used to quantify soil structure properties using a scanning electron micro- scope on thin sections prepared from the undisturbed soil cores. We found that total soil carbon was correlated with porosity, saturation percentage, and pore roughness. Pore roughness was correlated with crop production in gen- eral and with marketable production in particular. We found that the higher the complexity of the pore space, the more water retained in the soil, which may increase soil water residence and reduce plant water stress.

A Culture-Independent and Culture-Dependent Study of the Bacterial Community from the Bedrock Soil Interface

In nutrient limited soils, minerals constitute a major reservoir of bio-essential elements. Consequently, the release of nutritive elements during weathering is crucial. Bacteria have been shown to enhance weathering rates;however, there has been limited work that has focused on the bacterial weathering of bedrock or parent rock, which are the major sources of minerals, in nutrient limiting soils. In this study, both a culture-independent and culture-dependent approach was used to study the bacterial community at the interface between basaltic bedrock and nutrient limiting soil in Cadiar Idris region of Snowdonia National Park, United Kingdom. High throughput sequencing method, Ion Torrent, was used to characterise the bacterial community, which generated over 250,000 sequences. Taxonomical assignment demonstrated that approximately 50% (125,000 sequences) of the community consisted of the orders Actinomycetales, Burkholderiales, Clostridales, Bacillales, Rhizobiales and Acidobacterium, with unclassified sequences representing 44% ± 1.46% (110,000 ± 3650). Bacteria belonging to the genera Serratia, Pseudomonas, Bacillus, Paenibacillus, Chromobacterium, Janthinobacterium, Burkholderia and Arthrobacter, were isolated from the sample site. All of the isolates were able to grow in a minimal growth medium, which contained glucose, ammonium chloride with basalt as the sole source of bio-essential elements. Seventy percent of the isolates significantly enhanced basalt dissolution (p < 0.05). The rate of dissolution correlated to the production of oxalic acid and acidification of the growth medium. The findings of this work suggest that at the interface between bedrock and soil heterotrophic members of the bacterial community can enhance weathering, an essential part of biogeochemical cycling in nutrient limiting soil.

A Study of the Microbial Community at the Interface between Granite Bedrock and Soil Using a Culture-Independent and Culture-Dependent Approach

The dissolution of minerals plays an important role in the formation of soils and sediments. In nutrient limiting soils, minerals constitute a major reservoir of bio-essential cations. Of particular interest is granite as it is the major rock type of the continental land mass. Although certain bacteria have been shown to enhance weathering of granite-forming minerals, little is known about the dissolution of granite, at the whole rock scale, and the microbial community involved. In this study, both culture-independent and culture-dependent approaches were used to study the bacterial community at the interface between granite bedrock and nutrient limiting soil in Dartmoor National Park, United Kingdom. High throughput sequencing demonstrated that over 70% of the bacterial population consisted of the bacterial classes Bacilli, Beta-proteobacteria and Gamma-proteo-bacteria. Bacteria belonging to the genera Serratia, Pseudomonas, Bacillus, Paenibacillus, Chromo-bacterium and Burkholderia were isolated from the sample site. All of the isolates were able to grow in a minimal growth medium, which contained glucose and ammonium chloride, with granite as the sole source of bio-essential elements. Sixty six percent of the isolates significantly enhanced basalt dissolution (p < 0.05). Dissolution of Si, K, Ca and Mg correlated with production of oxalic acid and acidification. The results of this study suggest that microorganisms in nutrient limiting soils can enhance the rate of granite dissolution, which is an important part of the biogeochemical cycle.

Strong direct and indirect influences of climate change on water yield confirmed by the Budyko framework

Research findings concerning the main processes influencing water resources differ substantially,and so the topic remains controversial.Recent studies indicate that the changes in water yield,expressed through the n-parameter of Budyko framework,are associated with vegetation coverage changes.Here,we use runoffmeasurements and outputs from 13 dynamic global vegetation models,to investigate the underlying drivers of the n-parameter changes.Unlike previous studies,we instead find that climate change is the primary driver of adjustments on water resources.Changing climatic characteristics,particularly the intensity and seasonality of rainfall,modulates the runoffgeneration process.Indirect effects of climate change occur through altering vegetation properties,which in turn also impact river flow.We also find that in the arid and sparse vegetation regions,water yield is more sensitive to changes in n-parameter.Thus,the Budyko framework provides a reliable parameter-sparse representation of runoffchanges,and reveals that terrestrial water cycle is changing substantially under climate change.This climate forcing requires on-going investigation to generate more refined and reliable projections of future water availability.

Assessing the Risk of Impact of Farming Intensification on Calcareous Grasslands in Europe:A Quantitative Implementation of the MIRABEL Framework

农业措施的集约化仍然是欧洲生物多样性损失的一个主要驱动力，尽管已经实施了许多政策来逆转这个趋势。以前研究出来的一个叫做MIRABEL的概念框架，可以对农业集约化对生态上有价值的生境的影响进行专家本位的定量评价。我们利用最近出现的泛欧洲压力和处于风险中的生境的空间直观数据对以前的评价进行了定量升级。定量评价表明，欧洲潜在存在富营养化和过度放牧风险的石灰质草原的数量正在急速增加。1990～2000年之间发生的氮过剩和牲畜密度减少到生态极限以下的值很少。与此同时，相当大比例迄今为止农业集约化指标值较低的石灰质草原已经经历了1990～2000年之间的增长，在不久的将来可能会成为农业集约化的高风险区。因此，本评价是一个早期的警告信号，特别是对于那些位于传统上就进行密集农业的地区的生境来说。将本评价的结果与以往MIRABEL定性评价的结果相比较发现，如果泛欧洲的数据对于评价压力的强度是有效的，那就需要做更多的工作来识别生物多样性对这些压力的反应的地区差异。这时就应该利用基于地区专家的定性方法来补充数据驱动的评价。

毛竹小RNA高通量测序及病毒分析

以毛竹叶片为材料,采用小RNA高通量测序结合生物信息学对小RNA数据库进行组装,进一步分析了毛竹中存在的病毒和类病毒,并采用RT-PCR和RACE进行验证。结果表明:在竹子样品中存在水稻东格鲁病毒(RTBV),覆盖率达到91.0%。在毛竹样品中扩增得到1 992 bp RTBV病毒类似序列,占其基因组的24.9%。RTBV病毒在多个毛竹样品中存在且不存在多态性。RTBV病毒可能是一个古老的植物病毒,在进化过程中禾本科植物将其序列整合到基因组中来防御RTBV病毒的浸染。

蝴蝶在生境和生物小区之间的移位伴随着对外来蜜源的利用(英文)

在发育成熟的温带环境中,植食性昆虫群落能迅速适应引入植物并将其作为幼虫的食物和花蜜。我们研究了经过森林砍伐的热带环境中蝴蝶对利用引入植物作为蜜源植物的适应快慢程度,并研究了蝴蝶-显花植物在新的生物小区中出现的范围,发现蝴蝶对引入显花植物的利用和探访多于本地植物,这与引入植物在调查地点、生物小区和植物丰度中的普遍性有关。此外,取食花蜜的蝴蝶和显花植物与正在形成的的生物小区有关,例如路边、农田、集约耕地以及花园。在这些新生物小区中,引入植物很重要,因为它们为蝴蝶提供了蜜源。

GREENHOUSE GAS AND AMMONIA EMISSION MITIGATION PRIORITIES FOR UK POLICY TARGETS

Agriculture is essential for providing food and maintaining food security while concurrently delivering multiple other ecosystem services. However,agricultural systems are generally a net source of greenhouse gases and ammonia. They, therefore, need to substantively contribute to climate change mitigation and net zero ambitions. It is widely acknowledged that there is a need to further reduce and mitigate emissions across sectors, including agriculture to address the climate emergency and emissions gap. This discussion paper outlines a collation of opinions from a range of experts within agricultural research and advisory roles following a greenhouse gas and ammonia emission mitigation workshop held in the UK in March 2022. The meeting identified the top mitigation priorities within the UK's agricultural sector to achieve reductions in greenhouse gases and ammonia that are compatible with policy targets. In addition, experts provided an overview of what they believe are the key knowledge gaps, future opportunities and cobenefits to mitigation practices as well as indicating the potential barriers to uptake for mitigation scenarios discussed.

中欧和东欧国家生物多样性保护和人类活动之间的冲突

生物多样性和人类活动之间的冲突通常具有重要的政治、经济和环境响应,欧盟(EU)已经并将持续加强对这种冲突的关注。欧盟利用一整套自上而下和自下而上的方式来处理这些冲突,取得了不同程度的成功。欧洲目前面临的新挑战是10个新国家整合到欧盟的一体化,以及欧盟立法涵盖了一系列附加的生物多样性富集生境。中欧和东欧国家(CEEC)丰富的生物多样性很可能面临着这一一体化过程中某些方面的威胁,预计会出现一些生物多样性保护和人类活动之间的冲突。本文评述了中欧和东欧国家生物多样性保护和人类活动之间存在的一些冲突,预测了特别是新政策新立法执行后与欧盟一体化有关的冲突,最后,探讨了可能的冲突管理措施。

The Quadrennial Ozone Symposium 2016

1. Overview The 2016 Quadrennial Ozone Symposium （QOS-2016） was held on 4-9 September 2016 in Edinburgh, UK. The Symposium was organized by the International Ozone Commission （IO3C）, the NERC Centre for Ecology ＆ Hydrology and the University of Edinburgh, and was co-sponsored by the International Union of Geodesy and Geophysics, the International Association of Meteorology and Atmospheric Sciences, and the World Meteorological Organization.

Semantic linking of complex properties,monitoring processes and facilities in web-based representations of the environment

Where a virtual representation of the Earth must contain data values observed within the physical Earth system,data models are required that allow the integration of data across the silos of various Earth and environmental sciences domains.Creating a mapping between the well-defined terminologies of these silos is a stubborn problem.This paper presents a generalised ontology for use within Web 3.0 services,which builds on European Commission spatial data infrastructure models.The presented ontology acknowledges that there are many complexities to the description of environmental properties which can be observed within the physical Earth system.The ontology is shown to be flexible and robust enough to describe concepts drawn from a range of Earth science disciplines,including ecology,geochemistry,hydrology and oceanography.This paper also demonstrates the alignment and compatibility of the ontology with existing systems and shows applications in which the ontology may be deployed.

Nucleotide bias of DCL and AGO in plant anti-virus gene silencing

Plant Dicer-like(DCL)and Argonaute(AGO)are the key enzymes involved in anti-virus post-transcriptional gene silencing(AV-PTGS).Here we show that AV-PTGS exhibited nucleotide preference by calculating a relative AV-PTGS efficiency on processing viral RNA substrates.In comparison with genome sequences of dicot-infecting Turnip mosaic virus(TuMV)and monocot-infecting Cocksfoot streak virus(CSV),viral-derived small interfering RNAs(vsiRNAs)displayed positive correlations between AV-PTGS efficiency and G+C content(GC%).Further investigations on nucleotide contents revealed that the vsiRNA populations had G-biases.This finding was further supported by our analyses of previously reported vsiRNA populations in diverse plant-virus associations,and AGO associated Arabidopsis endogenous siRNA populations,indicating that plant AGOs operated with G-preference.We further propose a hypothesis that AV-PTGS imposes selection pressure(s)on the evolution of plant viruses.This hypothesis was supported when potyvirus genomes were analysed for evidence of GC elimination,suggesting that plant virus evolution to have low GC%genomes would have a unique function,which is to reduce the host AV-PTGS attack during infections.

Redevelopment of urban brownfield sites in China:Motivation,history,policies and improved management

Rapid urbanisation in China has resulted in an increased demand for land in towns and cities.To upgrade and modernise,China has also moved many major industries from urban centres to less populated areas.With the high economic value of urban land,the transformation and utilisation of brownfield areas have become important economically and socially.The Chinese government has recognised the need for strong frameworks to safeguard soil and groundwater quality,with brownfield sites a key category for management.Strong scientific,regulatory and decision-making frameworks are needed and being adopted to ensure practical,careful and wise use of central and localised government resources,to manage the reuse and regeneration of these brownfield sites.This paper reviews the context,policies and management procedures of developing brownfield sites in countries with a history of brownfield management and discusses China’s current situation and priorities for brownfield governance and redevelopment.These include(1)clarification of brownfield site soil contamination risk control standards and risk assessment procedures,(2)the responsibilities of different national and local agencies,(3)the establishment of a national expert committee to advise on best practices,policy and process,(4)the use of registered brownfield databases at national,provincial,municipal and county levels,and(5)the set up of soil pollution prevention fund at the provincial level.

Interaction between pollution and climate change augments ecological risk to a coastal ecosystem

Pollution and climate change are among the most challenging issues for countries with developing economies,but we know little about the ecological risks that result when these pressures occur together.We explored direct effects of,and interactions between,environmental pollution and climate change on ecosystem health in the Bohai Sea region of Northern China.We developed an integrated approach to assess ecological risks to this region under four scenarios of climate change.Although ecological risks to the system from pollution alone have been declining,interactions between pollution and climate change have enhanced ecological risks to this coastal/marine ecosystem.Our results suggest that current policies focused strictly on pollution control alone should be changed to take into account the interactive effects of climate change so as to better forecast and manage potential ecological risks.

Building the new international science of the agriculture-food-water-environment Nexus in China and the world

The multiple,complex and systemic problems of the agriculture-food-water-environment nexus(“Nexus”)are among the most significant challenges of the 21st century.China is a key site for Nexus research amidst profound socio-environmental problems.The policy implications of these problems have been authoritatively summarized elsewhere.This study presents discussions at an international workshop in Guangzhou that asked instead“What science is needed to deliver the growing policy commitments regarding these challenges?And,What changes are needed to the science itself?”Understanding and effective intervention regarding the Nexus calls for a paradigm shift:to a new kind of science of(capacity for)international,interdisciplinary,and impactful research working with and within complex socio-natural systems.We here argue that science must become proactive in approach,striving only for“minimal harm”not“silver bullet”solutions,and adopting an explicitly long-term strategic perspective.Together,these arguments lead to calls for reorienting science and science policy in three ways:from short-term remediation to longer-term optimization;from a focus on environmental threats to one on the opportunities for international collaborative learning;and toward supporting new forms of scientific career.We bring these points together by recommending a new form of scientific institution:a global network of collaborative Nexus Centres,under the umbrella of a global Food Nexus Organization akin to those of the human genome and proteome.

Terrestrial ecosystem health under long-term metal inputs:modeling and risk assessment

Metal contamination of soils may pose long-term risks to ecosystem health if not proper-ly managed.Future projection of contamination trends,coupled with ecological assessment,is needed to assess such risks.This can be achieved by coupling dynamic models of soil metal accumulation and loss with risk assessment on the basis of projected metal levels.In this study,we modeled the long-term dy-namics of Cu,Zn,and Cd in agricultural topsoils of a northern Chinese catchment(Guanting reservoir)and related projected metal levels to 2060 to ecological risk.Past metal dynamics were simulated using historical metal inputs from atmospheric deposition,irrigation,fertilizers,and animal manures.Model-ing future dynamics was done using scenarios of projected metal input rates.Ecological risk assessment was done using the Potentially Affected Fraction(PAF)approach to estimate the combined toxic pressure due to the three metals.Modeled labile soil metals agreed well with measurements from monitoring in 2009 following adjustment of the porewater dissolved organic concentration.Metals were predicted to be largely retained in the topsoil.Projections were sensitive to changes in imposed soil pH,organic mat-ter,and porewater dissolved organic carbon.Modeling suggests that decreases in input rates to between 5%and 7.5%of 2009 levels are required to prevent further accumulation.Computed PAFs suggest zinc makes the greatest contribution to ecological risk.Under the most conservative estimate of PAF,the threshold of potential ecological risk was reached before 2060 in two of the three future input scenarios.

Towards a better understanding of pathways of multiple co-occurring erosion processes on global cropland

Soil erosion is a complex process involving multiple natural and anthropic agents,causing the deterio-ration of multiple components comprising soil health.Here,we provide an estimate of the spatial pat-terns of cropland susceptibility to erosion by sheet and rill,gully,wind,tillage,and root crops harvesting and report the co-occurrence of these processes using a multi-model approach.In addition,to give a global overview of potential future changes,we identify the locations where these multiple concurrent soil erosion processes may be expected to intersect with projected dry/wet climate changes by 2070.Of a modelled 1.48 billion hectares(B ha)of global cropland,our results indicate that 0.56 B ha(-36%of the total area)are highly susceptible(classes 4 and 5)to a single erosion process,0.27 B ha(-18%of the total area)to two processes and 0.02 B ha(1.4%of the total area)to three or more processes.An estimated 0.82 B ha of croplands are susceptible to possible increases in water(0.68 B ha)and wind(0.14 B ha)erosion.We contend that the presented set of estimates represents a basis for enhancing our founda-tional knowledge on the geography of soil erosion at the global scale.The generated insight on multiple erosion processes can be a useful starting point for decision-makers working with ex-post and ex-ante policy evaluation of the UN Sustainable Development Goal 15(Life on Land)activities.Scientifically,this work provides the hitherto most comprehensive assessment of soil erosion risks at the global scale,based on state-of-the-art models.

Guiding phosphorus stewardship for multiple ecosystem services

The essential role of phosphorus(P)for agriculture and its impact on water quality has received decades of research attention.However,the benefits of sustainable P use and management for society due to its downstream impacts on multiple ecosystem services are rarely acknowledged.We propose a conceptual framework-the“phosphorus-ecosystem services cascade”(PESC)-to integrate the key ecosystem processes and functions that moderate the relationship between P released to the environment from human actions and ecosystem services at distinct spatial and temporal scales.Indirect pathways in the cascade via soil and aquatic processes link anthropogenic P to biodiversity and multiple services,including recreation,drinking water provision,and fisheries.As anthropogenic P cascades through catchments,it often shifts from a subsidy to a stressor of ecosystem services.Phosphorus stewardship can have emergent ecosystem service co-benefits due to synergies with other societal or management goals(e.g.,recycling of livestock manures and organic wastes could impact soil carbon storage).Applying the PESC framework,we identify key research priorities to align P stewardship with the management of multiple ecosystem services,such as incorporating additional services into agri-environmental P indices,assessing how widespread recycling of organic P sources could differentially impact agricultural yields and water quality,and accounting for shifting baselines in P stewardship due to climate change.Ultimately,P impacts depend on site-specific agricultural and biogeophysical contexts,so greater precision in targeting stewardship strategies to specific locations would help to optimize for ecosystem services and to more effectively internalize the downstream costs of farm nutrient management.

Ecosystem health towards sustainability

Ecosystems are becoming damaged or degraded as a result of stresses especially associated with human activities.A healthy ecosystem is essential to provide the services that humans and the natural environment require and has tremendous social and economic value.Exploration of the definition of ecosystem health includes what constitutes health and what it means to be healthy.To evaluate ecosystem health,it is necessary to quantify ecosystem conditions using a variety of indicators.In this paper,the main principles and criteria for indicator selection,classification of indicators for different kinds of ecosystems,the most appropriate indicators for measuring ecosystem sustainability,and various methods and models for the assessment of ecosystem health are presented.Drivers,sustainability,and resilience are considered to be critical factors for ecosystem health and its assessment.Effective integration of ecological understanding with socioeconomic,biophysical,biogeochemical,and public-policy dimensions is still the primary challenge in this field,and devising workable strategies to achieve and maintain ecosystem health is a key future challenge.

Vertical profiles of biogenic volatile organic compounds as observed online at a tower in Beijing

Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reactiontime of flight-mass spectrometry(PTR-ToF-MS) at heights of 3,15,32,64,and 102 m above the ground on the Institute of Atmospheric Physics(IAP) tower in central Beijing during the winter of 2016 and the summer of 2017.Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone.Isoprene mixing ratios were the highest at the 32 m in summer(1.64±0.66 ppbV) and at 15 m in winter(1.41±0.64 ppbV) with decreasing concentrations to the ground and to the 102 m,indicating emission from the tree canopy of the surrounding parks.Monoterpene mixing ratios were the highest at the 3 m height in both the winter(0.71±0.42 ppbV) and summer(0.16±0.10 ppbV) with a gradual decreasing trend to 102 m,indicting an emission from near the ground level.The lowest isoprene and monoterpene mixing ratios all occurred at 102 m,which were 0.71±0.42 ppbV(winter) and 1.35±0.51 ppbV(summer) for isoprene,and 0.42±0.22 ppbV(winter) and0.07±0.06 ppbV(summer) for monoterpenes.Isoprene in the summer and monoterpenes in the winter,as observed at the five heights,showed significant mutual correlations.In the winter monoterpenes were positively correlated with combustion tracers CO and acetonitrile at 3 m,suggesting possible anthropogenic sources.