@article {70,
	title = {Ammonia emission from field applied manure and its reduction{\textemdash}invited paper},
	journal = {European Journal of Agronomy},
	volume = {15},
	year = {2001},
	pages = {1-15},
	abstract = {Emissions of ammonia to the atmosphere are considered a threat to the environment and both United Nation treaty and European Union legislation increasingly limit emissions. Livestock farming is the major source of atmospheric NH3 in Europe and field applied manure contributes significantly to the emission of NH3 from
agriculture. This paper presents a review of studies of NH3 emission from field-applied animal manure and of the methods available for its reduction. It is shown that there is a complex relationship between the NH3 emission rate from slurry and the slurry composition, soil conditions and climate. It is concluded that simple empirical models cannot be used to predict ammonia emission from the wide range of circumstances found in European agriculture and
that a more mechanistic approach is required. NH3 emission from applied solid manure and poultry manure has been studied less intensively than slurry but appear to be controlled by similar mechanisms. The use of trail hoses, pre- or post-application cultivation, reduction in slurry viscosity, choice of application rate and timing and slurry injection were considered as reduction techniques. The most effective methods of reducing ammonia emissions were concluded to be incorporation of the animal slurry and farmyard manure or slurry injection. Incorporation should be as close to the application as possible, especially after slurry application, as loss rates are high in the 1st hours after application. Injection is a very efficient reduction technique, provided the slurry is applied at rates that can be contained in the furrows made by the injector tine.},
	keywords = {EPNB},
	author = {Sommer, S. G, Hutchings, N. J}
}
@article {73,
	title = {A detailed ammonia emission inventory for Denmark},
	journal = {Atmospheric Environment},
	volume = {35},
	year = {2001},
	abstract = {This paper describes the method used to create an ammonia inventory for Denmark and presents the emission factors used and their justi"cation. The total Danish emission for 1996 was 92,700 t NH4-N, with agriculture accounting for nearly 99\%. Emissions from animal manure accounted for 76\% of agricultural emissions. We conclude that there will be a continued demand for inventories based on emission factors, despite their lack of physical and chemical realism, but that they will become more complex. This will place increased demands on the statistical information available and on the knowledge of the underlying science.},
	keywords = {EPNB},
	author = {Hutchings, N. J and Sommer, S. G and Andersen, J. M and Asman, W. A. H}
}
@article {67,
	title = {Nitrogen balance and mineral nitrogen content in the soil in a long experiment with maize under different systems of N fertilization.},
	journal = {Plant Soil Environment},
	volume = {49},
	year = {2003},
	pages = {554-559},
	abstract = {The effect of different systems of N fertilization on nitrogen balance and N transformation in the soil was studied in
long-term stationary experiments (1991{\textendash}2002) with successive growing of maize. Average dry matter yield for the control
without fertilization in the period 1991{\textendash}2002 was 11.67 t of dry matter per ha, which was by 2{\textendash}2.9 t less than for
fertilization treatments. Statistically significant differences between the control and fertilization treatments were determined
for the first time in the 4th experimental year. Average nitrogen uptake by the aboveground biomass was 116 kg N/ha
for the control, 162{\textendash}170 kg N/ha for fertilization treatments. All experimental treatments had a negative balance of N inputs
and outputs, and it was {\textendash}1394 kg N/ha for the control (for 12 experimental years). After the application of mineral
fertilizers, a lower content of total carbon and nitrogen was measured in the topsoil compared to the control and treatments
with organic fertilization. The changes in the nitrogen regime of soil were characterized by the content of extractable
nitrogen and carbon in extractions by 0.01M CaCl2. With respect to the content of mineral nitrogen and easily
extractable organic nitrogen and carbon in the topsoil the control was most stable followed by farmyard manure treatment.
Soil lysimeters were installed in these experiments (depth 60 cm, size 0.2 m2). For an eight-year period (1994/2002)
11.78 kg N-NO3 {\textendash}/ha were determined in lysimetric waters. These values for fertilization treatments ranged from 21.0 to
58.2 kg N-NO3 {\textendash}/ha. Straw application reduced nitrate contents in lysimetric waters.},
	keywords = {EPNB},
	author = {Balik, J and Cerny, J and Tlustos, P and Zitkova, M}
}
@article {75,
	title = {Processes controlling ammonia emission from livestock slurry in the field},
	journal = {European Journal of Agronomy},
	volume = {19},
	year = {2003},
	pages = {465-486},
	abstract = {The processes of NH3 emission from field-applied slurry are reviewed and their relative importance assessed. In achieving this objective, the study served to focus on a number of features that have not previously been highlighted. These include the effect of the size of the area to which slurry is applied, the interaction between solar radiation input and wind speed, the role of the solid chemistry and the interaction between slurry NH4 and the slurry/soil cation exchange capacity (CEC). The most important processes controlling NH3 volatilisation were considered to be turbulent and molecular diffusion in the atmosphere, meteorological processes controlling evaporation and surface temperature, the ion production and buffering processes controlling the pH of the slurry/soil liquid, the solid chemistry that
determines precipitation of NH4  to slurry dry matter, the physical processes controlling the movement of slurry liquid into and within the soil, and the interaction of slurry liquid with soil CEC.},
	keywords = {EPNB},
	author = {Sommer, S. G and Genermont, S and Cellier, P and Hutchings, N. J and Olesen, J. E, Morvan, T}
}
@article {66,
	title = {Reducing nitrogen surplus from dairy farms. Effects of feeding and management.},
	journal = {Livestock Production Science},
	year = {2003},
	pages = {165-178},
	abstract = {The objective of the present paper is to review the factors which can affect N flow and surplus both at farm and at cow
level in order to point out areas with scope for future improvement. Special attention is given to management factors and
feeding. Besides information from the literature the paper is based on meta-analyses of our own and published results. With
regard to effects of production systems, mainly Danish surveys have been chosen as examples demonstrating the effects
obtained under practical conditions. A positive correlation between stocking rate and N surplus per hectare at farm gate level
is demonstrated, but there is also a considerable variation in N surplus per hectare at a given stocking rate. A number of
factors influencing N surplus and loss have been identified, and their impact on N surplus and production efficiency has been
estimated. N excretion per animal is an important factor for N turnover at farm level. Analysis of herd data indicates that
feeding strategy, breed and milk yield, together with energy conversion and the protein content of the diet, are important
factors explaining N excretion and N efficiency of cows. Reduction of N intake by optimal synchronisation of energy and
protein supply over time, especially in pasture-based systems, is one way of reducing N excretion from cows. Furthermore,
the ideal profile of absorbed amino acids should be identified, and models to estimate amino acid supply to the intestine
should be further improved. The effect of reducing N excretion from cows has to be evaluated at farm level as manure is
used as fertiliser for crop production. Overall, it seems possible to reduce the N surplus through better management and
feeding without reducing production efficiency.},
	keywords = {EPNB},
	author = {Borsting, C. F and Kristensen, T and Misciattelli, L and Hvelplund, T and Weisbjerg, M. R}
}
@article {76,
	title = {The development of the EMEP/CORINAIR Guidebook with respect to the emissions of different nitrogen and carbon species from animal production.},
	journal = {Agriculture, Ecosystems and Environment},
	volume = {112},
	year = {2006},
	abstract = {The reduction of emissions of air pollutants is subject of international conventions, which include reporting of emissions in accordance with guidelines or guidebooks provided. Within the Convention on the Long-range Transboundary Air Pollution, the Atmospheric Emission Inventory Guidebook describes the methodology. With respect to emissions from agricultural sources, in particular from animal husbandry, this guidebook at present undergoes major modifications: the calculation procedure making use of partial emission factors for the various sources of emissions (animal house, storage, manure application, etc.) is being replaced by a mass flow concept for both nitrogen and carbon species. The current state of the Guidebook, present activities to update it and future plans are described. The necessity to update both the Guidebook and the IPCC Guidelines as complementary tools to describe agricultural emissions and mass flows is emphasized.},
	keywords = {EPNB},
	author = {Daemmgen, U and Webb, J}
}
@article {68,
	title = {Nutrient losses from manure management in the European Union},
	journal = {Lifestock Science},
	volume = {112},
	year = {2007},
	pages = {261-272},
	abstract = {Manure management systems are conducive to nutrient and carbon losses, but the magnitude of the loss highly depends on the
nutrient element, the manure management system and the environmental conditions. This paper discusses manure management
systems in the 27 Member States of the European Union (EU-27) and nutrient losses from these systems, with emphasis on
nitrogen (N). In general, losses decrease in the order: C, NNNSNK, Na, Cl, BNP, Ca, Mg, metals. Assessments made with the
integrated modeling tool MITERRA-EUROPE indicate that the total N excretion in 2000 by livestock in EU-27 was \~{}10,400 kton.
About 65\% of the total N excretion was collected in barns and stored for some time prior to application to agricultural land. Almost
30\% of the N excreted in barns was lost during storage; approximately 19\% via NH3 emissions, 7\% via emissions of NO, N2O and
N2, and 4\% via leaching and run-off. Differences between Member States in mean N losses from manure storages were large (range
19.5{\textendash}35\%). Another 19\% of the N excreted in animal housing systems was lost via NH3 emissions following the application of the
manure to land. The results indicate that maximally 52\% of the N excreted in barns was effectively recycled as plant nutrient.
Various emission abatement measures can be implemented and have been implemented already in some Member States to reduce
the emissions of NH3 and N2O, and the leaching of N and P. There is scope to reduce NH3 emissions by \~{}30\% relative to the
reference year 2000, although the uncertainty in estimated emissions and in the estimated effects of emission abatement measures is
relatively large.},
	keywords = {EPNB},
	author = {Oenema, O and Oudendag, D and Velthof, G. L}
}
@article {71,
	title = {A whole-farm assessment of the efficacy of slurry acidification in reducing ammonia emissions},
	journal = {European Journal of Agronomy},
	volume = {28},
	year = {2007},
	pages = {148-154},
	abstract = {Livestock slurry in animal houses, in manure stores and applied on fields is in Denmark the most important source of ammonia (NH3) in the atmosphere. The emitted NH3 is a source of NH3 and ammonium (NH4 +) deposition, which causes eutrophication of N-deficient ecosystems and may form NH4 +-based particles in the air, which are a risk to health. This study examines the reductions in NH3 emissions from pig houses, manure stores and manure applied in the field achieved by acidifying the slurry in-house. Sulphuric acid was used to acidify pig slurry to pH < 6 and the system was constructed is such a way as to prevent foaming in the animal house as well as during storage. Acidification of the pig slurry reduced the NH3 emission from pig houses by 70\% compared with standard techniques. Acidification reduced NH3 emission from stored slurry to less than 10\% of the emission from untreated slurry, and the NH3 emission from applied slurry was reduced by 67\%. The mineral fertilizer equivalent (MFE) of acidified slurry was 43\% higher compared with the MFE of untreated slurry when applied to the soil. The odour emission from the slurry was not affected significantly by the treatment. The slurry acidification system is approved Best Available Technology (BAT) in Denmark.},
	keywords = {EPNB},
	author = {Kai, P and Pedersen, P and jensen, J. E and Hansen, M. N and Sommer, S. G}
}
@article {78,
	title = {Ammonia in the environment: From ancient times to the present},
	journal = {Environmental Pollution},
	volume = {156},
	year = {2008},
	pages = {583-604},
	abstract = {Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and
environmental impacts. This paper reviews the achievements and places them in their historical context.
It considers the role of ammonia in the development of agricultural science and air chemistry, showing
how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies
the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as
a compound of key human interest through the centuries, with a central role played by sal ammoniac in
alchemy and the emergence of modern science. The review highlights how recent environmental
research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize
the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams
and volcanoes. Present estimates of ammonia emissions from these sources are based on few
measurements, which should be a future priority.},
	keywords = {Air chemistry, Alchemy, Deposition, Emissions, EPNB, NH3 sal ammoniac, Nushadir},
	author = {Mark A. Sutton and Jan Willem Erisman and Frank Dentener and Detlev M{\"o}ller}
}
@article {65,
	title = {Emissions of gaseous nitrogen species from manure management: A new approach},
	journal = {Environmental Pollution},
	year = {2008},
	pages = {488-497},
	abstract = {A procedure for the assessment of emissions of nitrogen (N) species (ammonia, nitrous oxide, nitric oxide, di-nitrogen) from the manure
management system is developed, which treats N pools and flows including emissions strictly according to conservation of mass criteria. As
all relevant flows in the husbandry of mammals are depicted, the methodology is considered a Tier 3 approach in IPCC terminology or a detailed
methodology in UN ECE terminology. The importance of accounting for all N species is illustrated by comparing emission estimates obtained
using this approach with those obtained from the application the present detailed/Tier 2 methodology.},
	keywords = {EPNB},
	author = {Daemmgen, U and Hutchings, N. J}
}
@article {74,
	title = {A simple model for assessing ammonia emission from ammoniacal fertilisers as affected by pH and injection into soil},
	journal = {Atmospheric Environment},
	volume = {42},
	year = {2008},
	pages = {4656-4664},
	abstract = {Ammonia (NH3) volatilisation following the application of ammoniacal fertilisers and liquid manure to agricultural land is a significant source of atmospheric NH3, which not only poses a risk to the environment, but may also result in a loss of plant available nitrogen (N). This study examined the potential for reducing NH3 emission through acidifying an ammoniacal solution and by injecting the solution. The combination of the two technologies was studied and a model for predicting the most optimal treatment was developed. In the laboratory, ammonium (NH4 +) hydroxide (aqueous NH3) was dissolved in water (pH 11) and injected into a loamy sand soil. The NH3 emission was measured with a dynamic chamber technology. Injecting the solution to 10mm below the soil surface reduced NH3 emission by 10\% compared to surface application, and injection to 30mm reduced emission by 20\% compared to surface application. Acidifying the ammoniacal solution by adding sulphuric acid and reducing pH to 10 reduced the emission by 60\% at a 10mm injection depth and 90\% at 30mm compared with non-acidified and surface-spread ammoniacal solution. The results show that there is an important interaction of pH and injection depth and that there is a need for models predicting a combined effect. This type of model could contribute to reduce cost and energy (traction force) by providing the optimal combination of acidifying and injection depth that gives a specific reduction in NH3 emission, which in this study was reducing pH to 10 and inject the fertiliser to 30mm below surface. This study showed that relatively simple models can predict the NH3 emission from injected ammoniacal fertilisers, but that there is still a need for developing algorithms that predict the effect of pH, including the pH buffering capacity of the fertiliser and the soil.},
	keywords = {EPNB},
	author = {Nyord, T and Schelde, K. M and Sogaard, K. T and Jensen, L. S and Sommer, S. G}
}
@article {72,
	title = {Validation of model calculation of ammonia deposition in the neighbourhood of a poultry farm using measured NH3 concentrations and N deposition},
	journal = {Atmospheric Anvironment},
	volume = {43},
	year = {2008},
	abstract = {Substantial emission of ammonia (NH3) from animal houses and the related high local deposition of NH3- N are a threat to semi-natural nitrogen-deficient ecosystems situated near the NH3 source. In Denmark, there are regulations limiting the level of NH3 emission from livestock houses near N-deficient ecosystems that are likely to change due to nitrogen (N) enrichment caused by NH3 deposition. The models used for assessing NH3 emission from livestock production, therefore, need to be precise, as the regulation will affect both the nature of the ecosystem and the economy of the farmer. Therefore a study was carried out with the objective of validating the Danish model used to monitor NH3 transport, dispersion and deposition from and in the neighbourhood of a chicken farm. In the study we measured NH3 emission with standard flux measuring methods, NH3 concentrations at increasing distances from the chicken houses using passive diffusion samplers and deposition using 15N-enriched biomonitors and field plot studies. The dispersion and deposition of NH3 were modelled using the Danish OML-DEP
model. It was also shown that model calculations clearly reflect the measured NH3 concentration and N deposition. Deposition of N measured by biomonitors clearly reflected the variation in NH3 concentrations and showed that deposition was not significantly different from zero (P < 0.05) at distances greater
than 150{\textendash}200 m from these chicken houses. Calculations confirmed this, as calculated N deposition 320 m away from the chicken farm was only marginally affected by the NH3 emission from the farm. There was agreement between calculated and measured deposition showing that the model gives true estimates of the deposition in the neighbourhood of a livestock house emitting NH3},
	keywords = {EPNB},
	author = {Sommer, S. G and Ostergard, H. S and Lofstrom, P and Andersen, H. V and Jensen, L. S}
}
@article {77,
	title = {Hintergrundpapier zu einen multimedialen Stickstoffemissionsminderungs-Strategie},
	journal = {Umwelt Bundes Amt},
	year = {2009},
	keywords = {EPNB},
	author = {Geupel, Jering, Frey, Gohlisch, Lambrecht, Jaschinski, Koppe, M{\"o}nch, M{\"a}der, Nissler, Strogies, Mathan, Schneider, Mohaupt, Glant}
}
@article {69,
	title = {Ammonia emissions from mineral fertylisers and fertylised crops },
	journal = {Advances in Agronomy},
	volume = {82},
	year = {In Press},
	abstract = {A thorough understanding of the physical and chemical processes involved in NH3 emission from inorganic N fertilizers and fertilized crops is required
if reliable and operational NH3 emission factors and decision support systems for inorganic fertilizers are to be developed, taking into account the actual
soil properties, climatic conditions and management factors. For this reason, the present review focuses on processes involved in NH3 volatilization from
inorganic nitrogen fertilizers and the exchange of ammonia between crop foliage and the atmosphere. The proportion of nitrogen lost from N fertilizers due to NH3 volatilization may range from <0 to .50\%, depending on fertilizer type, environmental conditions (temperature, wind speed, rain), and soil properties (calcium
content, cation exchange capacity, acidity). The risk for high NH3 losses may be reduced by proper management strategies including, e.g., incorporation of
the fertilizer into the soil, use of acidic fertilizers on calcareous soils, use of fertilizers with a high content of carbonate-precipitating cations, split
applications to rice paddies or application to the soil surface beneath the crop canopy. The latter takes advantage of the relatively low wind speed
within well-developed canopies, reducing the rate of vertical NH3 transport and increasing foliar NH3 absorption. Conversely, NH3 is emitted from
the leaves when the internal NH3 concentration is higher than that in the ambient atmosphere as may often be the case, particularly during periods
with rapid N absorption by the roots or during senescence induced N-remobilization from leaves. Between 1 and 4\% of shoot N may be lost in this way.},
	keywords = {EPNB},
	author = {Sommer, S. G and Schjoerring, J. K and Denmead, O. D}
}
