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)

Temperate Grassland Yields and Nitrogen Uptake Are Influenced by Fertilizer Nitrogen Source

This research was supported under the National Development Plan through the Research Stimulus Fund administered by the Department of Agriculture, Food and the Marine (Grants RSF10-/RD/SC/716 and RSF11S138) and from the Department of Agriculture and Rural Development for Northern Ireland and by the Teagasc Walsh Fellowship Scheme.peer reviewedIn temperate grasslands, N source influences greenhouse gas emissions. Nitrification and urea hydrolysis inhibitors can reduce these losses. The objective of this study was to evaluate the impact of N source, urease inhibitors, and nitrification inhibitors on temperate grassland yields and N uptake. Experiments were conducted at three locations over 2 years (6 site-years) on the island of Ireland, covering a range of soils and climatic conditions. Results showed that calcium ammonium nitrate (CAN), urea+N-(n-butyl) thiophosphoric triamide (NBPT), urea+NBPT+dicyandiamide (DCD), and urea had equal annual dry matter yield. Urea+DCD had lower dry matter yield than CAN for 3 site-years. Calcium ammonium nitrate and urea+NBPT consistently had the same N uptake, urea+DCD had lower N uptake than CAN in 4 of 6 site-years, urea had lower N uptake than CAN in 2 site-years, and urea+NBPT+DCD had lower N uptake than CAN in 1 site-year. Urea+NBPT is a cost-effective alternative to CAN, which is consistently equal in terms of yield and N uptake in temperate grassland.Teagasc Walsh Fellowship ProgrammeDepartment of Agriculture and Rural Development for Northern IrelandDepartment of Agriculture, Food and the Marin

Effects of urease and nitrification inhibitors on yields and emissions in grassland and spring barley

We thank the Department of Agriculture, Food and the Marine (Grant No. 11/S/138), the Agricultural Greenhouse Gas Research Initiative for Ireland (Grant No. 10/RD/SC/716), Department of Agriculture, Environment and Rural Affairs, Northern Ireland and the Walsh Fellowship Scheme for the funding provide to Ms Mary Harty and Ms Leanne Roche.Conference paper presented to the International Fertiliser Society at a Conference in Cambridge, United Kingdom, on 9th December 2016.In trials conducted in the temperate maritime climate of Ireland on a range of acidic soils, calcium ammonium nitrate (CAN) and urea gave comparable yield performance. There was little evidence of reduced yields by using urea for grassland or spring barley. Our finding that urea produced annual yields that were not significantly different from CAN differs from previous studies which found that yields from urea were lower than those from ammonium nitrate or nitrate based fertiliser in the UK. However, there are also published results from trials conducted in temperate Irish grassland showing equal yield performance of CAN and urea in the 1970s. Based on yield performance and the cost of fertiliser there is scope to dramatically increase the level of urea usage in straight and blended fertilisers in the temperate maritime climate of Ireland in both grassland and spring barley. Such an increase will bring substantial benefits in terms of reducing direct nitrous oxide (N2O) emissions from fertiliser applied to soil, particularly in poorly draining soils subject to high levels of precipitation. Nitrogen recovery by plants tends to be more sensitive to differences in fertiliser efficiency than is yield. Although yields did not differ between urea and CAN; urea had a lower nitrogen recovery indicating that urea usage will also result in a reduced level of fertiliser use efficiency. Reduced efficiency is less tangible to farmers who tend to be primarily concerned with dependable yield results. Reduced efficiency is a problem nonetheless, particularly as it is closely linked to NH3 emissions in urea usage. European countries including Ireland have committed to reduce national NH3 emissions to comply with the revised National Emission Ceilings Directive (2001/81/EC) in Europe. Increased urea usage, which looks attractive from a yield, cost and direct N2O perspective in Ireland, runs counter to meeting these commitments. Additionally, NH3 is a source of indirect N2O emissions that will negate some of the N2O savings from urea. Due to the issues of yield dependability, fertiliser efficiency, N2O and NH3 emissions the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) is a particularly attractive option for making urea use more efficient by addressing its key weakness in the area of variable NH3 loss and efficiency. The urease inhibitor NBPT along with the nitrification inhibitor dicyandiamide (DCD) were tested with urea in comparison with calcium ammonium nitrate (CAN). The nitrification inhibitor DCD was very effective in reducing fertiliser N associated N2O emissions. Indeed, its usage allowed N2O levels to be reduced to levels comparable to where no application of N fertiliser was made at some site-years. However, at the DCD incorporation rate tested, DCD contributed to variability in NH3 loss from urea and suppressed both yield response and fertiliser efficiency. Use of the urease inhibitor NBPT in addition to DCD went a substantial way to resolving these shortcomings. Continuing work is needed to tailor the rate of existing and new urease and nitrification inhibitors to optimise the balance between suppression of gaseous N emissions, agronomic performance and economic considerations.We thank the Department of Agriculture, Food and the Marine (Grant No. 11/S/138), the Agricultural Greenhouse Gas Research Initiative for Ireland (Grant No. 10/RD/SC/716), Department of Agriculture, Environment and Rural Affairs, Northern Ireland and the Walsh Fellowship Scheme for the funding provide to Ms Mary Harty and Ms Leanne Roche

Biotic and abiotic predictors of potential N2O emissions from denitrification in Irish grasslands soils: A national-scale field study

Publication history: Accepted - 18 March 2022; Published - 25 March 2022.Large-scale information regarding nitrous oxide (N2O) emissions is needed as an evidence base to underpin land use policy and mitigation approaches. However, the highly variable rates of denitrification make the prediction of N2O emission demanding. Here, we evaluated the role of abiotic and biotic factors on the potential denitrification of Irish soils, in order to identify the key factors regulating potential N2O emissions at a large scale. To do so, we collected 136 soil samples from 32 sites across Ireland, and characterised the soil physico-chemical properties, the prokaryotic and fungal community composition, the abundance of N-cycling genes and evaluated the soil potential nitrification, denitrification and end product N2O/(N2O + N2). We found large differences in soil potential denitrification between sites (up to 41.5 mg N2O–N kg 1 soil day 1) with most of the emissions released in the form of N2O rather than N2. Soils with highest potential nitrification rates also exhibited the highest potential denitrification rates, and similar parameters were linked to both processes. The factors most predictive of soil potential denitrification were soil physico-chemical properties and the prokaryotic community composition. Soil phosphorus content was as important for predicting potential denitrification as was pH and total nitrogen. Soil microbial community structure, rather than denitrifier abundance, was an important predictor of the potential denitrification and the end-product N2O/(N2O + N2). The prokaryotic community composition was more strongly associated with denitrification rates and the resulting end-products than fungal communities. Increased relative abundance of the prokaryotic phyla Actinobacteriota and Crenarchaeota, were positively correlated to complete denitrification. Altogether, these results lay the foundation for a better understanding of the key factors regulating the potential denitrification in soils and identify important properties that enhance prediction of the potential denitrification at larger scales.This research and CD, JR and PRP were financially supported under the National Development Plan, through the Research Stimulus Fund, administered by the Irish Department of Agriculture, Food and the Marine (Grant number 15S655: MINE project)

Can the agronomic performance of urea equal calcium ammonium nitrate across nitrogen rates in temperate grassland?

Department of Agriculture, Environment and Rural Affairs in Northern Ireland, the Teagasc Walsh Fellowship Schemepeer-reviewedIn temperate grassland, urea has been shown to have lower nitrous oxide emissions compared to ammonium nitrate-based fertilizer and is less expensive. However, nitrogen (N) loss via ammonia volatilization from urea raises questions regarding yield performance and efficiency. This study compares the yield and N offtake of grass fertilized with urea, calcium ammonium nitrate (CAN) and urea treated with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) at six site-years. Five annual fertilizer N rates (100–500 kg N/ha) were applied in five equal splits of 20–100 kg N/ha during the growing season. On average, urea produced slightly better yields than CAN in spring (103.5% of CAN yield) and slightly poorer yields in summer (98.4% of CAN yield). There was no significant difference in annual grass yield between urea, CAN and urea + NBPT. Urea had the lowest cost per tonne of DM grass yield produced. However, the urea treatment had lower N offtake than CAN and this difference was more pronounced as the N rate increased. There was no difference in N offtake between urea + NBPT and CAN. While this study shows that urea produced yields comparable to CAN, urea apparent fertilizer N recovery (AFNR) tends to be lower. Urea selection in place of CAN will increase national ammonia emissions which is problematic for countries with targets to reduce ammonia emissions. Promisingly, NBPT allows the agronomic performance of urea to consistently equal CAN across N rates by addressing the ammonia loss limitations of urea.Department of Agriculture, Environment and Rural Affairs in Northern IrelandTeagasc Walsh Fellowship ProgrammeDepartment of Agriculture, Food and the Marin

La influencia de la posición anatómica sobre la capacidad de retención del agua y sobre la blandura de la carne de caballo

Cilj istraživanja bio je utvrditi sposobnost zadržavanja vode (kalo odmrzavanja, kalo kuhanja) i mekoću (silu presijecanja) najdužeg leđnog mišića (LT) i polutetivastog mišića (ST) konjskog mesa izuzetih nakon uobičajene klaoničke prakse. Prosječna vrijednost kala odmrzavanja LT mišića bila je 8,65 %, dok je prosječna vrijednost kala odmrzavanja ST mišića bila 6,69 %. Prosječna vrijednost kala kuhanja LT mišića bila je 19,35 %. Znatno veća prosječna vrijednost kala kuhanja utvrđena je u ST mišiću (23,41 %). Prosječna vrijednost sile presijecanja LT mišića bila je 28,10 N. Prosječna vrijednost sile presijecanja ST mišića bila je znatno veća od one utvrđene u LT mišiću te je iznosila 45,64 N. Usporednom analizom razlika srednjih vrijednosti kala odmrzavanja, kala kuhanja i mekoće utvrđene su statistički značajne razlike između LT i ST (p<0,0001) mišića konjskog mesa. Nadalje, rezultati potvrđuju umjereno visoku i pozitivnu korelaciju (r=0,60; p<0,0001) kala odmrzavanja između LT i ST mišića. Zaključno, anatomska pozicija je čimbenik kojeg je potrebno uzeti u obzir ne samo u istraživanjima nego i pri tehnološkoj obradi te izboru i kupnji konjskog mesa.The aim of the study was to investigate water-holding capacity (thawing loss, cooking loss) and tenderness (shear force) of longissimus thoracis muscle (LT) and semitendinosus muscle (ST) of horse meat. The thawing loss value for LT muscle was 8.65%, whereas for ST muscle was 6.69%. The cooking loss for LT muscle was 19.35%, whereas for ST muscle was 23.41%. The shear force for LT muscle was 28.10 N, whereas for ST muscle was higher (45.64 N). Paired t-test analysis showed significant differences for thawing loss, cooking loss, and shear force between LT and ST muscles (p<0.0001). Furthermore, the results showed high correlation (r=0.60; p<0.0001) for cooking loss between LT and ST muscles. Finally, it could be concluded that the anatomical location is a trait that surely must be considered in further investigations, in meat processing and purchasing of horse meat.Ziel dieser Arbeit bestand darin, das Wasserhaltevermögen (Wasserverlust beim Auftauen, Wasserverlust beim Kochen) und die Zartheit (Scherkraft) des längsten Rückenmuskels (LT) und des halbsehnigen Muskels (ST) beim Pferdefleisch zu untersuchen, deren Proben nach der üblichen Schlachtpraxis entnommen wurde. Der durchschnittliche Wert des Wasserverlusts beim Auftauen betrug beim LT Muskel 8,65%, während der durchschnittliche Wert des Wasserverlusts beim Auftauen beim ST Muskel 6,69% betrug. Der durchschnittliche Wert des Verlusts beim Kochen betrug beim LT Muskel 19,35%, während beim ST Muskel ein bedeutend höherer mittlerer Wert des Verlusts beim Kochen festgelegt wurde (23,41%). Der mittlere Wert der Scherkraft betrug beim LT Muskel 28,10 N. Der mittlere Wert der Scherkraft beim ST Muskel war mit einem Wert von 45,64 N bedeutend höher als beim LT Muskel. Bei einer vergleichenden Auswertung der mittleren Werte des Verlusts beim Auftauen, Kochen und bei der Zartheit wurden zwischen dem LT und ST Muskel beim Pferdefleisch statistisch relevante Unterschiede festgestellt (p<0,0001). Die Ergebnisse bestätigen darüber hinaus eine relativ hohe und positive Korrelation (r=0,60; p<0,0001) des Verlustes beim Auftauen zwischen dem LT und ST Muskel. Als Schlussfolgerung kann konstatiert werden, dass die anatomische Lage ein Faktor ist, der nicht nur bei Untersuchungen berücksichtigt werden sollte, sondern auch bei der technologischen Verarbeitung sowie bei der Wahl und dem Kauf von Pferdefleisch.Lo scopo della ricerca è consistito nell\u27accertare la capacità di trattenere l\u27acqua (calo da scongelamento, calo da cottura) e la tenerezza (forza di taglio) del muscolo lunghissimo (LT) e del muscolo semitendinoso (ST) della carne equina prelevati dopo la consueta prassi di macellazione. Circa il calo da scongelamento del muscolo LT, la ricerca ha evidenziato un valore medio dell\u278,65%, mentre, riguardo al calo da scongelamento del muscolo ST, ha evidenziato un valore medio del 6,69%. Circa il calo da cottura del muscolo LT, la ricerca ha evidenziato un valore medio del 19,35%. Il valore medio del calo da cottura evidenziato riguardo al muscolo ST è stato di molto maggiore (23,41%). Il valore medio della forza di taglio del muscolo LT è risultato di 28,10 N. Il valore medio della forza di taglio del muscolo ST, pari a 45,64 N, è risultato molto maggiore del valore medio registrato riguardo al muscolo LT. Mediante l\u27analisi comparativa delle differenze dei valori medi del calo da scongelamento, del calo da cottura e della tenerezza, sono state accertate differenze statisticamente significative tra il muscolo LT e il muscolo ST (p<0,0001) della carne equina. I risultati confermano anche una correlazione mediamente elevata e positiva (r=0,60; p<0,0001) del calo da scongelamento tra i muscoli LT e ST. In conclusione, la posizione anatomica è un fattore che va preso in considerazione non soltanto in sede di ricerca, ma anche nel processo tecnologico, nella scelta e nell\u27acquisto della carne equina.El fin de esta investigación fue determinar la capacidad de retención del agua (merma por descongelación, merma por cocción) y la blandura (fuerza de corte) del músculo más largo de la espalda (LT) y el músculo ST de la carne de caballo tomadas después de la práctica habitual en el matadero. El valor medio de la merma por descongelación del músculo LT fue 8,65%, mientras el valor medio de la merma por descongelación del músculo ST fue 6,69%. El valor medio de la merma por cocción del músculo LT fue 19,35%. El valor medio de la merma por cocción del músculo ST fue considerablemente más alto, (23,41%). El valor medio de la fuerza de corte del músculo LT fue 28,10 N. El valor medio de la fuerza de corte del músculo ST fue considerablemente más alto que el valor determinado para el músculo LT y fue 45,64 N. Por el análisis comparativo de los valores medio de la merma por descongelación, de la merma por cocción y de la blandura fueron determinadas diferencias estadísticamente significantes entre los músculos LT y ST (p<0,0001) de carne de caballo. Además, los resultados confirman la correlación positiva moderada (r=0,60; p<0,0001) de la merma por descongelación entre los músculos LT y ST. En conclusión, la posición anatómica es un factor que hay que tomar en cuenta no sólo en las investigaciones sino también durante el procesamiento tecnológico y en la compra de la carne de caballo

Gross nitrogen transformations in grassland soil react differently to urea stabilisers under laboratory and field conditions

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 RSF11S138) and from the Department of Agriculture, Environment and Rural Affairs for Northern Ireland. The first author gratefully acknowledges funding received from the Teagasc Walsh Fellowship Scheme.peer-reviewedA laboratory and a field study were conducted on a permanent grassland soil in Northern Ireland to investigate the effects of urea in combination with N process inhibitors such as the urease inhibitor N-(butyl) thiophosphoric triamide (NBPT) and/or the nitrification inhibitor dicyandiamide (DCD) on soil N dynamics. Urea enriched with n-butyl 15N to 60 atom % was applied to soil at a rate of 100 μg N g−1 dry soil in the laboratory and 100 kg N ha−1 in the field. A numerical 15N tracing model was used to quantify several simultaneously occurring gross N transformation rates in both studies. The changes in soil nitrate (NO3−) and ammonium (NH4+) concentrations and 15N enrichment over a 25-day period as well as the concentration and 15N enrichment of plant N at harvest were used to model soil gross N transformations. The results showed that the effect of N process inhibitors varied firstly between laboratory and field studies and secondly whether the inhibitors were applied individually or in combination. Overall DCD had a greater effect on the major soil N transformations than NBPT; reducing oxidation of NH4+, total nitrification, net NO3− produced, total mineralisation and the net adsorption of NH4+ at both laboratory and field scale. The effect of DCD was similar for these transformations whether applied alone or co-applied with NBPT. In contrast NBPT had no significant effect on oxidation of NH4+, total nitrification, total mineralisation or total immobilisation compared to urea in the field, while the effect on these transformations in the laboratory was significant. The contrasting effects of inhibitors on gross N transformations between laboratory and field may relate to the differences in experimental conditions, e.g. soil preparation, environmental conditions and the contribution of plant biomass. To obtain a more realistic assessment of gross soil N transformations in situ, it is essential that laboratory experiments are supplemented with field studies.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 RSF11S138) and from the Department of Agriculture, Environment and Rural Affairs for Northern Ireland. The first author gratefully acknowledges funding received from the Teagasc Walsh Fellowship Scheme

Differing effects of increasing calcium ammonium nitrate, urea and urea + NBPT fertiliser rates on nitrous oxide emission factors at six temperate grassland sites in Ireland

peer-reviewedThe present study evaluated the impact of three nitrogen (N) fertiliser formulations, applied at five N rates, on nitrous oxide (N2O) fluxes and annual direct N2O-N emission factors (EF) in temperate grassland. Closed static chambers were used to measure direct N2O fluxes at three geographically dispersed locations in Ireland over a two-year period, generating a total of 90 EFs across the six site-years and treatments. The three fertiliser formulations tested were calcium ammonium nitrate (CAN), urea, and urea amended with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) at 100, 200, 300, 400 and 500 kg N ha−1 yr−1. All treatments were applied in five equal split applications ranging from 20 to 100 kg N ha−1 split-1 over the growing season. The N2O-N EFs for CAN ranged from 0.39 − 4.68 with a mean of 1.62 (cv. 81 %), for urea from 0.04 – 1.7 with a mean of 0.46 (cv. 77 %) and for urea + NBPT from 0.18 – 1.7 with a mean of 0.60 (cv. 59 %). A significant positive relationship was found between the N rate and the annual N2O-N EFs in three (CAN), five (urea) and two (urea + NBPT) of six the site-years. For the remainder of the site-years EF was unaffected by N rate. These results indicate that fertiliser N choice and rate can be management factors that enable farmers to alter N2O losses in temperate grassland. Notably, the response of EF to increasing N rate was not consistent across the fertilisers, with the EF from urea being the most sensitive to the increasing N rate, urea + NBPT the least sensitive and CAN being intermediate. The accuracy of national greenhouse gas accounting could be improved by including N fertiliser formulation and its rate of application. Further research is also needed to understand the inconsistency in EF response to N rate across sites.Northern Ireland Department of Agriculture Environment and Rural Affair

Prospectively predicting Pseudomonas aeruginosa infection/s using routine data from the UK cystic fibrosis register

RATIONALE AND AIMS: Lung health of people with cystic fibrosis (PwCF) can be preserved by daily use of inhaled therapy. Adherence to inhaled therapy, therefore, provides an important process measure to understand the success of care and can be used as a quality indicator. Defining adherence is problematic, however, since the number of prescribed treatments varies considerably between PwCF. The problem is less pronounced among those with Pseudomonas aeruginosa (PA), for whom at least three daily doses of nebulized therapy should be prescribed and who thus constitute a more homogeneous group. The UK CF Registry provides routine data on PA status, but data are only available 12 months after collection. In this study, we aim to prospectively identify contemporary PA status from historic registry data.METHOD: UK CF Registry data from 2011 to 2015 for PwCF aged ≥16 was used to determine a pragmatic prediction rule for identifying contemporary PA status using historic registry data. Accuracy of three different prediction rules was assessed using the positive predictive value (PPV). The number and proportion of adults predicted to have PA infection were determined overall and per center for the selected prediction rule. Known characteristics linked to PA status were explored to ensure the robustness of the prediction rule.RESULTS: Having CF Registry defined chronic PA status in the two previous years is the selected definition to predict a patient will have PA infection within the current year (population-level PPV = 96%-97%, centre level PPV = 85%-100%). This approach provides a subset of data between 1852 and 1872 patients overall and a range of 8 to 279 patients per center.CONCLUSION: Historic registry data can be used to contemporaneously identify a subgroup of patients with chronic PA. Since this patient group has a narrower treatment schedule, this can facilitate a better benchmarking of adherence across centers.</p

Linkages between extracellular enzyme activities and the carbon and nitrogen content of grassland soils

International audienceImportant biochemical reactions in soils are catalyzed by extracellular enzymes, which are synthesized by microbes and plant roots. Although enzyme activities can significantly affect the decomposition of soil organic matter and thus influence the storage and cycling of carbon (C) and nitrogen (N), it is not clear how enzyme activities relate to changes in the C and N content of different grassland soils. Here we address whether the activity of C-acquiring (b-1,4-glucosidase, BG) and N-acquiring (L-leucine amino-peptidase (LAP) and b-1,4-N-acetyl-glucosaminidase (NAG)) enzymes is linked to changes in the C and N content of a variety of human-managed grassland soils. We selected soils which have a well-documented management history going back at least 19 years in relation to changes in land use (grazing, mowing, ploughing), nutrient fertilization and lime (CaCO 3) applications. Overall we found a positive relationship between BG activity and soil C content as well as between LAP þ NAG activity and soil N. These positive relationships occurred across grasslands with very different soil pH and management history but not in intensively managed grasslands where increases in soil bulk density (i.e. high soil compaction) negatively affected enzyme activity. We also found evidence that chronic nutrient fertilization contributed to increases in soil C content and this was associated with a significant increase in BG activity when compared to unfertilized soils. Our study suggests that while the activities of C-and N-acquiring soil enzymes are positively related to soil C and N content, these activities respond significantly to changes in management (i.e. soil compaction and nutrient fertilization). In particular, the link between BG activity and the C content of long-term fertilized soils deserves further investigation if we wish to improve our understanding of the C sequestration potential of human-managed grassland soils