The effect of precipitation and application rate on dicyandiamide persistence and efficiency in two Irish grassland soils

peer-reviewedThe nitrification inhibitor dicyandiamide (DCD) has had variable success in reducing nitrate (NO3-) leaching and nitrous oxide (N2O) emissions from soils receiving nitrogen (N) fertilisers. Factors such as soil type, temperature and moisture have been linked to the variable efficacy of DCD. Since DCD is water soluble it can be leached from the rooting zone where it is intended to inhibit nitrification. Intact soil columns (15 cm diameter by 35 cm long) were taken from luvic gleysol and haplic cambisol grassland sites and placed in growth chambers. DCD was applied at 15 or 30 kg DCD ha-1, with high or low precipitation. Leaching of DCD, mineral N and the residual soil DCD concentrations were determined over eight weeks High precipitation increased DCD in leachate and decreased recovery in soil. A soil x DCD rate interaction was detected for the DCD unaccounted (proxy for degraded DCD). In the cambisol degradation of DCD was high (circa 81%) and unaffected by DCD rate. In contrast DCD degradation in the gleysol was lower and differentially affected by rate, 67 and 46% for the 15 and 30 kg ha-1 treatments, respectively. Differences DCD degradation rates between soils may be related to differences in organic matter content and associated microbiological activity. Variable degradation rates of DCD in soil, unrelated to temperature or moisture, may contribute to varying DCD efficacy. Soil properties should be considered when tailoring DCD strategies for improving nitrogen use efficiency and crop yields, through the reduction of reactive nitrogen loss.This research was financially supported under the National Development Plan, through the Research Stimulus Fund, administered by the Department of Agriculture, Food and the Marine under grants 07519 and 07545

Mustard catch crop enhances denitrification in shallow groundwater beneath a spring barley field

The study was funded by Department of Agriculture and Food through the Research Stimulus Fund Programme (Grant RSF 06383) in collaboration with the Department of Civil, Structural & Environmental Engineering, Trinity College Dublin, Ireland.peer-reviewedOver-winter green cover crops have been reported to increase dissolved organic carbon (DOC) concentrations in groundwater, which can be used as an energy source for denitrifiers. This study investigates the impact of a mustard catch crop on in situ denitrification and nitrous oxide (N2O) emissions from an aquifer overlain by arable land. Denitrification rates and N2O-N/(N2O-N + N2-N) mole fractions were measured in situ with a push–pull method in shallow groundwater under a spring barley system in experimental plots with and without a mustard cover crop. The results suggest that a mustard cover crop could substantially enhance reduction of groundwater nitrate NO3--N via denitrification without significantly increasing N2O emissions. Mean total denitrification (TDN) rates below mustard cover crop and no cover crop were 7.61 and 0.002 μg kg−1 d−1, respectively. Estimated N2O-N/(N2O-N + N2-N) ratios, being 0.001 and 1.0 below mustard cover crop and no cover crop respectively, indicate that denitrification below mustard cover crop reduces N2O to N2, unlike the plot with no cover crop. The observed enhanced denitrification under the mustard cover crop may result from the higher groundwater DOC under mustard cover crop (1.53 mg L−1) than no cover crop (0.90 mg L−1) being added by the root exudates and root masses of mustard. This study gives insights into the missing piece in agricultural nitrogen (N) balance and groundwater derived N2O emissions under arable land and thus helps minimise the uncertainty in agricultural N and N2O-N balances

Improving and disaggregating N2O emission factors for ruminant excreta on temperate pasture soils

pre-printCattle excreta deposited on grazed grasslands are a major source of the greenhouse gas (GHG) nitrous oxide (N2O). Currently, many countries use the IPCC default emission factor (EF) of 2% to estimate excreta-derived N2O emissions. However, emissions can vary greatly depending on the type of excreta (dung or urine), soil type and timing of application. Therefore three experiments were conducted to quantify excreta-derived N2O emissions and their associated EFs, and to assess the effect of soil type, season of application and type of excreta on the magnitude of losses. Cattle dung, urine and artificial urine treatments were applied in spring, summer and autumn to three temperate grassland sites with varying soil and weather conditions. Nitrous oxide emissions were measured from the three experiments over 12 months to generate annual N2O emission factors. The EFs from urine treated soil was greater (0.30–4.81% for real urine and 0.13–3.82% for synthetic urine) when compared with dung (− 0.02–1.48%) treatments. Nitrous oxide emissions were driven by environmental conditions and could be predicted by rainfall and temperature before, and soil moisture deficit after application; highlighting the potential for a decision support tool to reduce N2O emissions by modifying grazing management based on these parameters. Emission factors varied seasonally with the highest EFs in autumn and were also dependent on soil type, with the lowest EFs observed from well-drained and the highest from imperfectly drained soil. The EFs averaged 0.31 and 1.18% for cattle dung and urine, respectively, both of which were considerably lower than the IPCC default value of 2%. These results support both lowering and disaggregating EFs by excreta type.This research was financially supported under the National Development Plan, through the Research Stimulus Fund, administered by the Department of Agriculture, Food and the Marine (Grant numbers RSF10/RD/SC/716 and 11S138)

Museomics of a rare taxon: placing Whalleyanidae in the Lepidoptera Tree of Life

https://doi.org/10.1111/syen.12503Museomics is a valuable approach that utilizes the diverse biobanks that are natural history museums. The ability to sequence genomes from old specimens has expanded not only the variety of interesting taxa available to study but also the scope of questions that can be investigated in order to further knowledge about biodiversity. Here, we present whole genome sequencing results from the enigmatic genus Whalleyana (comprising two species - occurring in drier biomes of Madagascar - previously placed in a monotypic superfamily, Whalleyanoidea), as well as from certain species of the families Callidulidae and Hyblaeidae (Calliduloidea and Hyblaeoidea, respectively). Library preparation was carried out on four museum specimens and one existing DNA extract and sequenced with Illumina short reads. De novo assembly resulted in highly fragmented genomes with the N50 ranging from 317 to 2078 bp. Mining of a manually curated gene set of 331 genes from these draft genomes had an overall gene recovery rate of 64-90%. Phylogenetic analysis places Whalleyana as sister to Callidulidae and Hyblaea as sister to Pyraloidea. Since the former sister-group relationship turns out to be also supported by ten morphological synapomorphies, we propose to formally assign the Whalleyanidae to the superfamily Calliduloidea. These results highlight the usefulness of not only museum specimens but also existing DNA extracts, for whole genome sequencing and gene mining for phylogenomic studies.Peer reviewe

Cardiac safety in cluster headache patients using the very high dose of verapamil (≥720 mg/day)

Use of high doses of verapamil in preventive treatment of cluster headache (CH) is limited by cardiac toxicity. We systematically assess the cardiac safety of the very high dose of verapamil (verapamil VHD) in CH patients. Our work was a study performed in two French headache centers (Marseilles–Nice) from 12/2005 to 12/2008. CH patients treated with verapamil VHD (≥720 mg) were considered with a systematic electrocardiogram (EKG) monitoring. Among 200 CH patients, 29 (14.8%) used verapamil VHD (877 ± 227 mg/day). Incidence of EKG changes was 38% (11/29). Seven (24%) patients presented bradycardia considered as nonserious adverse event (NSAE) and four (14%) patients presented arrhythmia (heart block) considered as serious adverse event (SAE). Patients with EKG changes (1,003 ± 295 mg/day) were taking higher doses than those without EKG changes (800 ± 143 mg/day), but doses were similar in patients with SAE (990 ± 316 mg/day) and those with NSAE (1,011 ± 309 mg/day). Around three-quarters (8/11) of patients presented a delayed-onset cardiac adverse event (delay ≥2 years). Our work confirms the need for systematic EKG monitoring in CH patients treated with verapamil. Such cardiac safety assessment must be continued even for patients using VHD without any adverse event for a long time

Improving monitoring techniques by exploiting TerraSAR-X data: an application to Campi Flegrei (Naples, Italy)

Geodetic monitoring of the Neapolitan Volcanic District, including the Campi Flegrei caldera on the west of the city of Naples (Italy), is carried out via an integration between ground based networks and space-borne DInSAR techniques, exploiting the SAR sensors onboard ERS1-2 and ENVISAT satellites. This allowed, for instance, to follow the time evolution of the small uplift events which took place in 2000 and 2005-2006. Unfortunately, the use of the ENVISAT C-band could result sometimes in no information when dealing with very low deformation rates, as in the 2005-2006 case, when only continuous ground stations were able to detect the very beginning of the uplift event. To overcome this problem, from December 2009 we decided to use an high resolution SAR sensor operating in the X band, i.e. TerraSAR-X from DLR. TerraSAR-X High Resolution Spotlight scenes covering the main part of the Campi Flegrei caldera and centred on the Solfatara crater were used for a DInSAR analysis, using the GENESIS DLR’s software. The first two scenes (Dec. 15 and 26) were acquired with a temporal baseline of only one repetition cycle (11 days) and formed an interferogram with a very small perpendicular baseline (16.5 m). Apart from some minor atmospheric effects, the interferogram shows a small but clear deformation signal in the Pisciarelli area, close to the east side of the Solfatara crater. The ellipse shaped uplift area extends approximately 30 meters in E-W and 20 meters in N-S directions and the maximum deformation is up to 10 mm in the centre of the uplifted area. The availability of a new scene (06/01/2010) allowed three possible combinations. The deformation event highlighted by this analysis is consistent with geochemical observations carried out in Pisciarelli by INGV-OV. Pisciarelli area is seat of a fumarolic field systematically monitored in the frame of the volcanic surveillance of the Campi Flegrei caldera. Two field surveys highlighted that, during the period of SAR images acquisition, a new and strong fumarolic vent appeared in the centre of the uplifted area. In fact the vent, firstly observed on Dec. 21, was absent on Dec. 16. The two independent observations, field surveys and SAR data, suggest that the opening of the fumarolic vent was preceded by the pressurization of a small part of the fumarolic field highlighted by the documented uplift. The correlation between the dynamics of the fumarolic field and the deformation signal is confirmed by the fact that in the 26/12/2009-06/01/2010 interferogram the deformation signal is no more detectable. Finally, this case proves the high potentiality of TerraSAR-X High Resolution Spotlight data in monitoring volcanic activity with a resolution suitable for detecting also minor, but possibly dangerous, changes of the systems, as it could be in the early recognition of the signals generated by impending phreatic eruptions. TerraSAR-X High Resolution Spotlight acquisitions will continue every cycle and PS-InSAR and SBAS algorithms will be applied to carefully monitor any further changes in the activity of the Campi Flegrei volcanic system

Poultry farm vulnerability and risk of avian influenza re-emergence in Thailand

Highly pathogenic avian influenza (HPAI) remains of concern as a major potential global threat. This article evaluates and discusses the level of vulnerability of medium and small-scale commercial poultry production systems in Thailand related to avian influenza virus re-emergence. We developed a survey on 173 farms in Nakhon Pathom province to identify the global level of vulnerability of farms, and to determine which type of farms appears to be more vulnerable. We used official regulations (the Good Agricultural Practices and Livestock Farm Standards regulations) as a reference to check whether these regulations are respected. The results show that numerous vulnerability factors subsist and could represent, in case of HPAI re-emergence, a significant risk for a large spread of the disease. Bio-security, farm management and agro-commercial practices are particularly significant on that matter: results show that these practices still need a thorough improvement on a majority of farms. Farms producing eggs (especially duck eggs) are more vulnerable than farms producing meat. Those results are consistent with the type of farms that were mostly affected during the 2004–2008 outbreaks in Thailand

The interactive effects of various nitrogen fertiliser formulations applied to urine patches on nitrous oxide emissions in grassland

peer-reviewedPasture-based livestock agriculture is a major source of greenhouse gas (GHG) nitrous oxide (N2O). Although a body of research is available on the effect of urine patch N or fertiliser N on N2O emissions, limited data is available on the effect of fertiliser N applied to patches of urinary N, which can cover up to a fifth of the yearly grazed area. This study investigated whether the sum of N2O emissions from urine and a range of N fertilisers, calcium ammonium nitrate (CAN) or urea ± urease inhibitor ± nitrification inhibitor, applied alone (disaggregated and re-aggregated) approximated the N2O emission of urine and fertiliser N applied together (aggregated). Application of fertiliser to urine patches did not significantly increase either the cumulative yearly N2O emissions or the N2O emission factor in comparison to urine and fertiliser applied separately with the emissions re-aggregated. However, there was a consistent trend for approximately 20% underestimation of N2O loss generated from fertiliser and urine applied separately when compared to figures generated when urine and fertiliser were applied together. N2O emission factors from fertilisers were 0.02%, 0.06%, 0.17% and 0.25% from urea ± dicyandiamide (DCD), urea + N-(n-butyl) thiophosphoric triamide (NBPT) + DCD, urea + NBPT and urea, respectively, while the emission factor for urine alone was 0.33%. Calcium ammonium nitrate and urea did not interact differently with urine even when the urea included DCD. N2O losses could be reduced by switching from CAN to urea-based fertilisers

In situ denitrification rates in shallow groundwater beneath a springbarley - mustard cover crop system

Abstract of Conference poster presentatio