Modelling spatial and inter-annual variations of nitrous oxide emissions from UK cropland and grasslands using DailyDayCent

This work contributes to the Defra funded projects AC0116: ‘Improving the nitrous oxide inventory’, and AC0114: ‘Data Synthesis, Management and Modelling’. Funding for this work was provided by the UK Department for Environment, Food and Rural Affairs (Defra) AC0116 and AC0114, the Department of Agriculture, Environment and Rural Affairs for Northern Ireland, the Scottish Government and the Welsh Government. Rothamsted Research receives strategic funding from the Biotechnology and Biological Sciences Research Council. This study also contributes to the projects: N-Circle (BB/N013484/1), U-GRASS (NE/M016900/1) and GREENHOUSE (NE/K002589/1).Peer reviewedPublisher PD

Greenhouse gas and ammonia emission mitigation priorities for UK policy targets

Acknowledgements Many thanks to the Association of Applied Biologist’s for organising and hosting the ‘Agricultural greenhouse gases and ammonia mitigation: Solutions, challenges, and opportunities’ workshop. This work was supported with funding from the Scottish Government’s Strategic Research Programme (2022-2027, C2-1 SRUC) and BBSRC (BBS/E/C/000I0320 and BBS/E/C/000I0330). We also acknowledge support from UKRI694 BBSRC (United Kingdom Research and Innovation-Biotechnology and Biological Sciences 695 Research Council; United Kingdom) via grants BBS/E/C/000I0320 and BBS/E/C/000I0330. and Rothamsted Research's Science Initiative Catalyst Award (SICA) supported by BBSRC.Peer reviewedPublisher PD

Retention of As and Sb in ombrotrophic peat bogs: records of As, Sb and Pb depositiona at four Scottish sites

Possible postdepositional As migration in ombrotrophic peat bogs was investigated by comparing depth profiles of As with those of Sb and Pb, two elements considered to be essentially immobile in peat, and those of redox-sensitive, potentially mobile nutrient elements such as Mn, Fe, P, and S in 210Pb-dated cores from four Scottish bogs. Concentration profiles of As were similar to those of Sb and Pb rather than these other elements, indicating that As is bound strongly to organic matter and is relatively immobile in ombrotrophic peat. Historical records of atmospheric anthropogenic As, Sb, and Pb deposition during the industrial and postindustrial periods were derived, site-specific maxima (up to 1.55, 1.33, and 45 mg m−2 y−1, respectively) occurring between the late 1890s and 1960s, reflecting emissions from diverse sources such as mining and smelting, coal combustion, and also, in the case of Pb, exhaust emissions from the use of leaded gasoline. Since the mid-1980s, fluxes of Pb decreased (4−7 fold) more rapidly than those of As and Sb (2−3 fold), attributable to both the gradual elimination of leaded gasoline and recent new sources of the latter elements. Relative trends in derived anthropogenic As, Sb, and Pb deposition largely agreed with other Scottish peat and moss archive records, direct measurements of deposition, and UK emissions, i.e., four different types of data source

Scottish peat bog records of atmospheric vanadium deposition over the past 150 years: comparison with other records and emission trends

Cores from four Scottish ombrotrophic peat bogs were used to reconstruct the historical record of atmospheric vanadium (V) deposition in Scotland over the last 150 years. The general similarity of V and Pb concentration profile trends in 210Pb-dated cores from each of the sites strongly suggested that V, like Pb, is essentially immobile in ombrotrophic peat. After allowance via use of the conservative element Ti for the contribution of soil dust V, the deposition of anthropogenic V was found to be greatest (1.3 to 2.0 mg m−2 y−1) in the mid-20th century before decreasing to 0.1–0.3 mg m−2 y−1 in the early years of the 21st century. The latter values were in good agreement with directly measured atmospheric V fluxes at nearby sites, a finding also observed in the case of Pb. The decline in peat-core-derived fluxes for both V and Pb from 1970 to 2004, however, was not as large as the decline in official UK emission estimates for the two metals during this period. This, along with an order of magnitude discrepancy between the anthropogenic V/Pb ratios at the peat core surface and the higher values of the ratio for UK emissions in the early 2000s, suggests that the recently revised UK emissions data for V may perhaps still be overestimated and/or that some previously deposited Pb is being resuspended in the atmosphere

A comparisonof antimony and lead profiles over the past 2500 years in Flanders Moss ombrotrophic peat bog, Scotland

Two cores collected in 2001 and 2004 from Flanders Moss ombrotrophic peat bog in central Scotland were dated (14C, 210Pb) and analysed (ICP-OES, ICP-MS) to derive and compare the historical atmospheric deposition records of Sb and Pb over the past 2500 years. After correction, via Sc, for contributions from soil dust, depositional fluxes of Sb and Pb peaked from ca. 1920-1960 A.D., with >95% of the anthropogenic inventories deposited post-1800 A.D. Over the past two centuries, trends in Sb and Pb deposition have been broadly similar, with fluctuations in the anthropogenic Sb/Pb ratio reflecting temporal variations in the relative input from emission sources such as the mining and smelting of Pb ores (in which Sb is commonly present, as at Leadhills/Wanlockhead in southern Scotland), combustion of coal (for which the Sb/Pb ratio is approximately an order of magnitude greater than in Pb ores) and exhaust emissions (Pb from leaded petrol) and abrasion products from the brake linings (Sb from heat-resistant Sb compounds) of automobiles. The influence of leaded petrol has been most noticeable in recent decades, firstly through the resultant minima in Sb/Pb and 206Pb/207Pb ratios (the latter arising from the use of less radiogenic Australian Pb in alkylPb additives) and then, during its phasing out and the adoption of unleaded petrol, complete by 2000 A.D., the subsequent increase in both Sb/Pb and 206Pb/207Pb ratios. The extent of the 20th century maximum anthropogenic enrichment of Sb and Pb, relative to the natural Sc-normalised levels of the Upper Continental Crust, was similar at approximately 50- to 100-fold. Prior to 1800 A.D., the influence of metallurgical activities on Sb and Pb concentrations in the peat cores during both the Mediaeval and Roman/pre-Roman periods was discernible, small Sb and Pb peaks during the latter appearing attributable, on the basis of Pb isotopic composition, to the mining/smelting of Pb ores indigenous to Britain

Historical accumulation rates of mercury in four Scottish ombrotrophic peat bogs over the past 2000 years

The historical accumulation rates of mercury resulting from atmospheric deposition to four Scottish ombrotrophic peat bogs, Turclossie Moss (northeast Scotland), Flanders Moss (west-central), Red Moss of Balerno (east-central) and Carsegowan Moss (southwest), were determined via analysis of 210Pb- and 14C-dated cores up to 2000 years old. Average pre-industrial rates of mercury accumulation of 4.5 and 3.7 μg m− 2 y− 1 were obtained for Flanders Moss (A.D. 1–1800) and Red Moss of Balerno (A.D. 800–1800), respectively. Thereafter, mercury accumulation rates increased to typical maximum values of 51, 61, 77 and 85 μg m− 2 y− 1, recorded at different times possibly reflecting local/regional influences during the first 70 years of the 20th century, at the four sites (TM, FM, RM, CM), before declining to a mean value of 27 ± 15 μg m− 2 y− 1 during the late 1990s/early 2000s. Comparison of such trends for mercury with those for lead and arsenic in the cores and also with direct data for the declining UK emissions of these three elements since 1970 suggested that a substantial proportion of the mercury deposited at these sites over the past few decades originated from outwith the UK, with contributions to wet and dry deposition arising from long-range transport of mercury released by sources such as combustion of coal. Confidence in the chronological reliability of these core-derived trends in absolute and relative accumulation of mercury, at least since the 19th century, was provided by the excellent agreement between the corresponding detailed and characteristic temporal trends in the 206Pb/207Pb isotopic ratio of lead in the 210Pb-dated Turclossie Moss core and those in archival Scottish Sphagnum moss samples of known date of collection. The possibility of some longer-term loss of volatile mercury released from diagenetically altered older peat cannot, however, be excluded by the findings of this study

Soil compaction effects on grassland silage yields and soil structure under different levels of compaction over three years

Soil compaction has been estimated to be responsible for 33 million ha of soil degradation in Europe, reducing crop yields, however there is limited data on grassland silage yields loss. Extended grazing periods, increased size and weight of farm vehicles and more extreme weather have fostered concern over the consequences of grassland management on reduced grass yield and soil quality. This work aimed at studying the effect of increased animal trampling and mechanical (tractor) soil compaction on grassland silage mean dry matter (DM) yields and soil structure over a three year period at two UK sites. These sites were on two established perennial ryegrass fields with contrasting soil textures; an imperfectly drained silty clay loam in SW Scotland and a well drained sandy loam from central England. Results showed trampling and tractor compaction decreased mean DM yields over three years and by the third year DM yield for the trampled area was 11.4% less on the soil with greater clay content soil and 12.0% less on the more sandier soil than the no compaction control. DM yield for the tractor compaction, by the third year, was 14.5% less than no compaction DM yield, on both soil types. Compaction treatments gave the greatest reductions for the first silage cut DM yields annually, for both soil types. The largest reductions (19.0% for trampling and 37.7% for tractor) were on the soil with the greater clay content in the second year, with the coolest start to the growing season. Compaction reduced N uptake, decreased drainage and increased water filled pore spaces (WFPS). Linear regression of visual evaluation of soil structure (VESS) scores and bulk densities provided evidence that VESS is an effective tool for detecting grassland compaction and would assist with the management of moderately compacted soils where deteriorate soil conditions may result in yield loss