Tolerable versus actual soil erosion rates in Europe

Erosion is a major threat to soil resources in Europe, and may impair their ability to deliver a range of ecosystem goods and services. This is reflected by the European Commission's Thematic Strategy for Soil Protection, which recommends an indicator-based approach for monitoring soil erosion. Defined baseline and threshold values are essential for the evaluation of soil monitoring data. Therefore, accurate spatial data on both soil loss and soil genesis are required, especially in the light of predicted changes in climate patterns, notably frequency, seasonal distribution and intensity of precipitation. Rates of soil loss are reported that have been measured, modelled or inferred for most types of soil erosion in a variety of landscapes, by studies across the spectrum of the Earth sciences. Natural rates of soil formation can be used as a basis for setting tolerable soil erosion rates, with soil formation consisting of mineral weathering as well as dust deposition. This paper reviews the concept of tolerable soil erosion and summarises current knowledge on rates of soil formation, which are then compared to rates of soil erosion by known erosion types, for assessment of soil erosion monitoring at the European scale

On-farm benefits from soil organic matter in England and Wales

Soil organic carbon (SOC) is increasingly recognised as an important component in the global carbon cycle and as a potential C sequestration pool for mitigation of the enhanced greenhouse effect. Recent appeals have prompted research into the potential of storing C in arable fields and the concomitant impact for on-farm economics. This project was instigated to answer the question “Does soil organic matter (SOM), or its management, provide arable on-farm benefit, in England and Wales?”. A methodological design was developed which integrates social science with soil science. From the National Soil inventory (NSI) database, attainable SOC ranges were estimated for different SOC physiotopes, i.e. landscape units for which the environmental factors governing SOC contents are similar. Significant differences were found, e.g for a dry-sandy physiotope and a wet-clayey physiotope, the ranges were estimated at 0.5-1.6% and 2.0-5.4% SOC (w/w), respectively. A list of qualified ‘SOM benefit’ indicators was developed using an iterative process involving the scientific literature and interviews with ‘expert farmers’. Perceptions of the indicators were investigated within a stratified random sample of commercial farmers. On balance, farmers perceived that benefits of SOM outweighed the disbenefits (i.e. lodging, weeds, and slugs). N fertiliser reduction, increased yield quantity, and enhanced ease of tillage were recognised as the most valuable benefits. However, the values were low to moderate, and perceived to be influenced substantially by physiotope, crop type, and SOM management type. Farmers’ perceptions and valuations were investigated for 101 fields on commercial farms, selected from the NSI database to represent the attainable SOC content ranges. No correlations were found between SOC and any performance indicator. The full range of reported performances was found for fields with similar SOC contents. This implied that SOC contents and SOM management may have little importance to on-farm economics when compared to the quality of overall farm management. These results expose the marginal extent of on-farm benefits from increased SOC contents and SOM management. Implications for future research and policy are discussed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Representativeness of European biochar research : part II – pot and laboratory studies

Biochar research is extensive and there are many pot and laboratory studies carried out in Europe to investigate the mechanistic understanding that govern its impact on soil processes. A survey was conducted in order to find out how representative these studies under controlled experimental conditions are of actual environmental conditions in Europe and biomass availability and conversion technologies. The survey consisted of various key questions related to types of soil and biochar used, experimental conditions and effects of biochar additions on soil chemical, biological and physical properties. This representativeness study showed that soil texture and soil organic carbon contents used by researchers are well reflected in the current biochar research in Europe (through comparison with published literature), but less so for soil pH and soil type. This study provides scope for future work to complement existing research findings, avoiding unnecessary repetitions and highlighting existing research gaps.Peer reviewe

Representativeness of European biochar research: part II–pot and laboratory studies

Biochar research is extensive and there are many pot and laboratory studies carried out in Europe to investigate the mechanistic understanding that govern its impact on soil processes. A survey was conducted in order to find out how representative these studies under controlled experimental conditions are of actual environmental conditions in Europe and biomass availability and conversion technologies. The survey consisted of various key questions related to types of soil and biochar used, experimental conditions and effects of biochar additions on soil chemical, biological and physical properties. This representativeness study showed that soil texture and soil organic carbon contents used by researchers are well reflected in the current biochar research in Europe (through comparison with published literature), but less so for soil pH and soil type. This study provides scope for future work to complement existing research findings, avoiding unnecessary repetitions and highlighting existing research gaps. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group]

Gas-phase metallicity profiles of the Bluedisk galaxies: Is metallicity in a local star formation regulated equilibrium?

As part of the Bluedisk survey, we analyse the radial gas-phase metallicity profiles of 50 late-type galaxies. We compare the metallicity profiles of a sample of H I-rich galaxies against a control sample of H I-`normal' galaxies. We find the metallicity gradient of a galaxy to be strongly correlated with its H I mass fraction (M(H I) / M_{*}). We note that some galaxies exhibit a steeper metallicity profile in the outer disc than in the inner disc. These galaxies are found in both the H I-rich and control samples. This contradicts a previous indication that these outer drops are exclusive to H I-rich galaxies. These effects are not driven by bars, although we do find some indication that barred galaxies have flatter metallicity profiles. By applying a simple analytical model, we are able to account for the variety of metallicity profiles that the two samples present. The success of this model implies that the metallicity in these isolated galaxies may be in a local equilibrium, regulated by star formation. This insight could provide an explanation of the observed local mass-metallicity relation

The MeerKAT Fornax Survey

We present the science case and observations plan of the MeerKAT Fornax Survey, an HI and radio continuum survey of the Fornax galaxy cluster to be carried out with the SKA precursor MeerKAT. Fornax is the second most massive cluster within 20 Mpc and the largest nearby cluster in the southern hemisphere. Its low X-ray luminosity makes it representative of the environment where most galaxies live and where substantial galaxy evolution takes place. Fornax's ongoing growth makes it an excellent laboratory for studying the assembly of clusters, the physics of gas accretion and stripping in galaxies falling in the cluster, and the connection between these processes and the neutral medium in the cosmic web. We will observe a region of 12 deg$^2$ reaching a projected distance of 1.5 Mpc from the cluster centre. This will cover a wide range of environment density out to the outskirts of the cluster, where gas-rich in-falling groups are found. We will: study the HI morphology of resolved galaxies down to a column density of a few times 1e+19 cm$^{-2}$ at a resolution of 1 kpc; measure the slope of the HI mass function down to M(HI) 5e+5 M(sun); and attempt to detect HI in the cosmic web reaching a column density of 1e+18 cm$^{-2}$ at a resolution of 10 kpc.Comment: Proceedings of Science, "MeerKAT Science: On the Pathway to the SKA", Stellenbosch, 25-27 May 201

Representativeness of European biochar research : Part I - field experiments

A representativeness survey of existing European Biochar field experiments within the Biochar COST Action TD1107 was conducted to gather key information for setting up future experiments and collaborations, and to minimise duplication of efforts amongst European researchers. Woody feedstock biochar, applied without organic or inorganic fertiliser appears over-represented compared to other categories, especially considering the availability of crop residues, manures, and other organic waste streams and the efforts towards achieving a zero waste economy. Fertile arable soils were also over-represented while shallow unfertile soils were under-represented. Many of the latter are likely in agroforestry or forest plantation land use. The most studied theme was crop production. However, other themes that can provide evidence of mechanisms, as well as potential undesired side-effects, were relatively well represented. Biochar use for soil contamination remediation was the least represented theme; further work is needed to identify which specific contaminants, or mixtures of contaminants, have the potential for remediation by different biochars.Peer reviewe

Biochar standardization and legislation harmonization

It is a relatively new concept to use biochar as soil amendment and for climate change mitigation. For this reason, the national and supranational legislation in the EU is not yet adequately prepared to regulate both the production and the application of biochar. Driven by this “regulatory gap”, voluntary biochar quality standards have been formed in Europe with the European Biochar Certificate, in the UK with the Biochar Quality Mandate and in the USA with the IBI Standard which is intended to be used internationally. In parallel to this, biochar producers and biochar users in a number of EU countries were partly successful in fitting the new biochar product into the existing national legislation for fertilisers, soil improvers and composts. The intended revision of the EC Regulation 2003/2003 on fertilisers offers the opportunity to regulate the use of biochar at the EU level. This publication summarizes the efforts on biochar standardization which have been carried out by voluntary products standards and illustrates existing legislation in EU member states, which apply to the production and use of biochar. It describes existing and planned EU regulations, which impact biochar applications and it develops recommendations on the harmonization of biochar legislation in the EU.  First published online: 24 Jan 201

Representativeness of European biochar research: part I–field experiments

A representativeness survey of existing European Biochar field experiments within the Biochar COST Action TD1107 was conducted to gather key information for setting up future experiments and collaborations, and to minimise duplication of efforts amongst European researchers. Woody feedstock biochar, applied without organic or inorganic fertiliser appears over-represented compared to other categories, especially considering the availability of crop residues, manures, and other organic waste streams and the efforts towards achieving a zero waste economy. Fertile arable soils were also over-represented while shallow unfertile soils were under-represented. Many of the latter are likely in agroforestry or forest plantation land use. The most studied theme was crop production. However, other themes that can provide evidence of mechanisms, as well as potential undesired side-effects, were relatively well represented. Biochar use for soil contamination remediation was the least represented theme; further work is needed to identify which specific contaminants, or mixtures of contaminants, have the potential for remediation by different biochars. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group]

The Bluedisks project, a study of unusually H I-rich galaxies - I. H I sizes and morphology

<p>We introduce the 'Bluedisk' project, a large programme at the Westerbork Synthesis Radio Telescope that has mapped the H i in a sample of 23 nearby galaxies with unusually high H i mass fractions, along with a similar-sized sample of control galaxies. This paper presents the sample selection, observational set-up, data reduction strategy and a first analysis of the sizes and structural properties of the H i discs. We find that the H i-rich galaxies lie on the same H i mass versus H i size relation as normal spiral galaxies, extending it to total H i masses of 2 x 10(10) M-circle dot and radii R1 of similar to 100 kpc. The H i-rich galaxies have significantly larger values of H i-to-optical size ratio and more clumpy H i discs than those of normal spirals. There is no evidence that the discs of H i-rich galaxies are more disturbed. In fact, the centre of the H i distribution corresponds more closely with the centre of the optical light in the H i-rich galaxies than in the controls. All these results argue against a scenario in which new gas has been brought in by mergers. It is possible that they may be more consistent with cooling from a surrounding quasi-static halo of warm/hot gas.</p>