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Modelling ammonia volatilization from animal slurry trail hose applied to cereals
Abstract
In Europe ammonia (NH3), volatilization from animal manure is the major source of NH3 in the atmosphere. From March to July 1997, NH3 volatilization from trail hose applied slurry was measured for seven days after application in six experiments. A statistical analysis of data showed that NH3 volatilization rate during the first 4–5 h after slurry application increased significantly (P<5%) with wind speed and soil slurry surface water content. NH3 volatilization in the six measuring periods during the experiments increased significantly (P<5%) with relative water content of the soil slurry surface, global radiation, pH, and decreased with increasing rainfall during each measuring period and rainfall accumulated from onset of each experiment. A mechanistic model of NH3 volatilization was developed. Model inputs are climate variables, soil characteristics and total ammoniacal nitrogen (TAN=ammonium+ammonia) in the soil surface layer. A pH submodel for predicting pH at the surface of the soil slurry liquid was developed. The measured NH3 volatilization was compared with model simulations. The simulated results explained 27% of the variation in measured NH3 volatilization rates during all seven days, but 48% of measured volatilization rates during the first 24 h. Calculations with the model showed that applying slurry in the morning or in the afternoon reduced volatilization by 50% compared with a noon application. Spreading the slurry with trail hoses to a 60 cm high crop reduced losses by 75% compared with a spreading onto bare soil. Ammonia volatilization was 50% lower when the soil had dried out after slurry application compared with a wet slurry surface.
... The effects of rainfall and relative humidity on NH 3 loss were not consistent in different studies. Generally, rainfall could suppress ammonia volatilization (Gordon and Schuepp, 1994;Sommer and Olesen, 2000), but increase NH 3 loss if it occurred within one hour before urea application (Kissel et al., 2004). Cabrera et al. (2010) has reported that relatively high initial soil water content followed by consistently higher air relative humidity (RH) at the height of 2 m led to larger NH 3 loss. ...
... Diversely, NH 3 flux of applying urea at dusk generally didn't peak on the day of fertilization, and maximum of that was only 33.69 g N ha − 1 h − 1 appearing at noon of the next day. Moreover, cumulative NH 3 loss with application timing of dusk could be significantly reduced compared to the morning and noon, which was in good agreement with the result of Gordon et al. (2001) and Sommer and Olesen (2000). The significant reduction of NH 3 loss by applying urea at dusk for sprinkler fertigation might because the changes in meteorological parameters within a day. ...
... Furthermore, under sprinkler fertigation in 2017, significant positive correlation was also obtained between radiation and NH 3 loss. That might because radiation can contribute to heating of the soil surface where liquid NH 3 is in equilibrium with the atmospheric NH 3 (Sommer et al. 2000). In addition, instantaneous NH 3 flux was negatively correlated with relative humidity under sprinkler fertigation in 2017, which was consistent with the result reported by Nathan and Malzer (1994). ...
Ammonia (NH3) volatilization from agricultural activities contributes to climate change and nitrogen (N) loss. Nitrogen management method has an important effect on NH3 volatilization. The purpose of this study was to evaluate the influence of N application rate, method and timing on NH3 loss from alfalfa field. In 2017 and 2018, NH3 volatilization was measured by the calibrated Dräger-Tube method under banding, surface broadcasting and center-pivot fertigation methods with three N application rates (27.6, 48.3, 69.0 kg N ha⁻¹ for each alfalfa cutting). Different application timing (7:00, 12:00, 17:00) was applied for sprinkler fertigation in 2017. The results showed that with irrigation method of center pivot, the two-year averaged cumulative NH3 loss under sprinkler fertigation was 6.80 kg N ha⁻¹, was similar to that under broadcasting and 32.55 % higher than that under banding. With the increase of N application rates, the cumulative NH3 loss increased but NH3 loss rate decreased. For different treatments, NH3 loss rate ranged from 1.76 % to 3.88 %. Cumulative NH3 loss for a growing season was only 5.00 kg N ha⁻¹ for sprinkler fertigation at dusk, which could be significantly reduced by 20.38 % and 23.31 % compared with those in the morning and at noon, and even lower than that under banding. Meanwhile, instantaneous NH3 loss flux had a significantly positive correlation with temperature in the two years. Based on our results, in order to minimize NH3 loss, sprinkler fertigation at dusk was more recommendable to the urea application for alfalfa in the North China.
... Un modèle est par définition ce que l'on reproduit par imitation (Loubet, 2000 Goh (1984-1985) dynamic Génermont and Cellier (1997) dynamic B.S. +F.C. slurry ** ** yes cognitive + predictive Sommer and Olesen (2000) dynamic BS + crops + F.C. slurry ** ** cognitive + predictive Wu et al. (2003) dynamic B.S. + F.C. swine slurry ** ** yes cognitive + predictive. ...
... L'isotherme d'échange est rarement pris en compte sauf dans le modèle de Fleisher et al. (1987). Les deux grandes paramétrisations des constantes acido-basique et de Henry en fonction de la température sont celles de Hales et Drewes (1979) utilisée par van der Molen et al. (1990a, b) ou de Beutier et Renon (1978), utilisée par Génermont et Cellier (1997), Sommer et Olesen (2000) et Wu et al. (2003). La particularité des modèles de Rachhpal- Singh et Nye (1986a, b, c) et de Fleisher et al. (1987) -seuls modèles conçus à partir d'expérimentations de laboratoire et pour des fertilisants minéraux -est de ne pas proposer de corrections de la constante d'acidité en fonction de la température ce qui les rend non utilisables en l'état pour des études au champ. ...
... Cette paramétrisation est celle qui se rapproche le plus d'une modélisation empirique. Le terme de transfert peut être également calculé par la somme des différentes résistances (résistance dans la couche limite de surface, résistance de la couche limite atmosphérique et résistance du sol) s'opposant au transfert d'ammoniac (Sommer et Olesen, 2000 ;van der Molen et al., 1990a, b). Cette approche a l'avantage de tenir compte des conditions de stabilité de l'atmosphère, mais deux des résistances impliquées (couche limite atmosphérique et sol) sont calculées de façon empirique. ...
*UMR INRA INAPG Environnement et Grandes Cultures de Grignon Diffusion du document : UMR INRA INAPG Environnement et Grandes Cultures de Grignon Diplôme : Dr. Ing.
... As a consequence, NH 3 emission from anaerobi- Fig. 4. Effect of crop height on the reduction in NH 3 emission from slurry after application with trail hoses. Emissions are related to NH 3 emission from slurry broadspread to soil or crops (adapted from data in Sommer et al., 1997 andOlesen, 2000). 5. Reduction in NH 3 emission due to application technique related to ammonia losses from animal slurry broadspread onto soil or a plant covered soil (from Dö hler, 1991; Kowalewsky, 1990;Pain et al., 1990c;Klarenbeek and Bruins, 1991;Phillips et al., 1991;Sommer and Petersen, 1992;Larsen et al., 1992;Rubaek et al., 1996;Sommer and Ersbøll, 1994;Bless et al., 1991;Thompson et al., 1987). ...
... Choosing to apply manure when conditions do not favour volatilisation may reduce losses of NH 3 , e.g. during the coolest part of the day or when rain is expected. It has been calculated, that avoiding applications during times of the day with a high potential for NH 3 losses could reduce the total emission of NH 3 from applied slurry by half (Sommer and Olesen, 2000). How useful this technique may be in practice will depend on the farmer's flexibility in the choice of application date and time. ...
... ln(DM) 4 Y is the mean solar radiation for the period (W m −2 ) +0.067Y 5 is the soil water content, l (H 2 O) l −1 pH=7.87-0.52(ln ) 2 0-6 days F c = F *(−0.011+0.914x) 0-6 h Emission F c from manure applied with trail hoses to a cereal 6 crop, x is crop height (cm) Sources: (1) ; (2) ; (3) Bussink et al. (1994); (4) Braschkat et al. (1997); (5) Sommer and Olesen (2000); (6) Calculated through linear regression of data from the articles of and Sommer and Olesen (2000). Fig. 6. ...
... The factors that control the NH3 flux were soil NH4 + , water input (irrigation and precipitation), soil pH, air temperature, and wind speed [42][43][44][45]. After being applied to the soil, urea hydrolyzes firstly. ...
... [51] also proved that AV rate from soil irrigated immediately following fertilizer application is considerably higher than that from soil irrigated 5 h after fertilization. However, too much water input has the potential to carry urea or BS into the soil, minimizing loss of volatilization [7,38,45]. Previous studies found that rainfall increased infiltration of NH4 + into the soil, contributing to a reduction in AV. In this study, after rainfall on 23 and 24 July, AV decreased due to the loss of NH4 + concentration. ...
Digestate and biogas slurry (BS) are the byproduct of biogas engineering that could be used for elevating plant growth. However, the consequent emissions of ammonia from BS are considered a severe threat to the atmosphere. Herein, we conducted two consecutive field experiments with wheat–maize rotations to find out the optimum ratio of BS to combine with chemical fertilizer (CF) to reduce ammonia volatilization (AV) while keeping the stable crop yield. In maize season, 226.5 kg N/ha of CF was applied. In wheat season, 226.5 kg N/ha was applied at different ratios (100%, 80%, and 50%) between BS and CF. Our results found that the maximum yield of 6250 kg/ha was produced by CF, and this yield could be obtained through a combined application of 38% BS mixed with CF. Highest AV produced of 16.08 kg/ha by CF. BS treatments significantly reduced the emission from 18% to 32% in comparison to CF. The combined application of BS-CF produced the highest yield due to essential nutrients coming from both BS-CF. Subsequently, it reduced the AV depending on fertilizer type and fertilizer rate. An optimal ratio of 38% BS was recommended to produce the highest yield and lowest ammonia emissions. The application of BS together with different ratios of CF could be an alternative agricultural strategy to obtain desired crop yield and reduce AV in North China Plain (NCP).
... In both years, application dependent NH3 volatilization showed the same trends, whereas the dimension of gaseous NH3 losses was strongly regulated by environmental factors. The strong effect of environmental factors on NH3 release has also been reported by Mattila (2006); ; and Sommer and Olesen (2000). Thus, the comparison of NH3 volatilization between different studies may become difficult if environmental conditions are not comparable. ...
... Results from banded slurry application without incorporation were in accordance with the results from and Sommer and Olesen (2000) and showed that, given bare soil, surface application without incorporation is only an alternative for farmers, if infiltration is guaranteed through rainfalls immediately after application. This result also verifies the current German legislation which prohibits leaving slurry on the surface of bare soils (DüV, 2017). ...
In a time of climate change and against the background of intensive animal husbandry and biogas production in Germany, strategies for mitigation of greenhouse gas (GHG) release and Nitrogen (N) losses from silage maize production become increasingly important, especially for organic fertilizers. Consequently, the main objective of this study was to determine the height of GHG release from silage maize production on a medium textured soil which is typical for this region in Southwest Germany and to evaluate useful fertilization opportunities to mitigate carbon dioxide (CO2) footprint per yield unit. To identify management factors improving GHG budget from silage maize, annual nitrous oxide (N2O) and methane (CH4) measurements were carried out during maize growth and subsequent black fallow at least weekly. Investigations were conducted over two years on two adjacent fields (one for each study year). Amounts of ammonia (NH3) volatilizations after fertilization and nitrate (NO3-) leaching losses were also included in GHG balances. In dependence on available data, determined or estimated values were used. Additionally, yield and N removal from maize plants were quantified. The basic treatments of this study which investigated impact of fertilizer form and application techniques, were an unfertilized control (CON), a mineral fertilization (MIN), a banded cattle slurry application by trailing hose and subsequent incorporation (INC) and a cattle slurry injection (INJ). As confirmed repeatedly, in contrast to broadcast slurry incorporation, slurry injection efficiently reduced the risk of NH3 losses by direct slurry placement into the soil, but simultaneously provoked N2O formation more strongly, probably due to the anaerobic conditions in the injection slot favoring denitrification. For reducing N2O release from slurry injection, the applicability of six single or combined nitrification inhibitors (NIs) concerning potential GHG reduction were investigated. This N2O reduction should be reached through the desynchronized availability of carbon (C) and NO3-, derived from nitrified slurry ammonium (NH4+). Thus, in the period after slurry application, N2O losses from denitrification as well as from nitrification should be reduced through NIs. For final evaluation, collection of measured and estimated data (including direct and indirect N2O losses (NH3, NO3-), CH4 budget, pre-chain emissions from mineral fertilizer and fuel consumption) were converted into CO2 equivalents and summarized as area- or yield-related GHG balances. Except for one of the INJ treatments with NI (exclusively investigated in the first year) and one INC treatment with NI (exclusively investigated in the second year), all remaining treatments were tested in both experimental years. The height of NH3 emissions from INC treatment (12-23 % of applied NH4+-N) was more weather-dependent than those from INJ treatment (12-15 % of applied NH4+-N). In mean over both years, cumulative N2O emission from INJ treatment (13.8 kg N2O-N ha-1 yr-1), was significantly higher than from CON, MIN, and INC which recorded 2.8, 4.7, and 4.4 kg N2O-N ha-1 yr-1. NIs decreased the fertilization-induced N2O emissions from injection by 36 % (mean over all NIs and years) by an order of magnitude comparable to slurry incorporation. The NIs investigated tended to be categorized in inhibitors with prior and delayed inhibitory maximum. Whether low persistence, or poor biological degradability was an advantage, depended on environmental conditions. A combination of two NIs, one with putative prior and one with delayed release behavior reached the highest N2O reduction. In the additional INC treatment, this NI combination tended to reduce annual N2O release by 20 % in comparison to incorporation without inhibitor. Beside the potential of reducing fertilization-induced N2O emissions, NIs might also help to improve CH4 budgets in silage maize production. In general, CON, MIN and INC were net CH4 sinks in both years with mean uptakes of 460, 127, and 793 g CH4-C ha-1 yr-1, respectively. Conversely, slurry injection resulted in net CH4 emissions of 3144 g CH4-C ha-1 yr-1 (mean over both years). However, NIs tended to reduce CH4 emissions from injection by around 48 % and increased CH4 consumption from slurry incorporation by 20 %. Across all treatments and years, direct N2O emissions were the major contributor to total GHG balance. Yield-related GHG budgets from both years were lowest for CON, followed by INC or MIN treatment and significantly highest for sole slurry injection. NIs decreased fertilization-induced GHG release from injection in mean over both years by order of magnitude comparable with slurry incorporation. Consequently, alongside slurry incorporation and broadcast mineral fertilization, slurry injection combined with recommended NIs was evaluated as an equally appropriate fertilization strategy in terms of the atmospheric burden for livestock farmers.
... Ammonia volatilization from land applied slurry is reduced by trailing hose/shoe application (band spreading) (Sommer et al., 1997). However, the NH3 reduction effect of band spreading is in general higher when used in growing crops (Sommer et al., 2000;Smith et al., 2000), due to lower temperatures and wind speeds in the crop canopy and due to leaf absorption of emitted NH3 (Sommer et al. 1997). Nevertheless, to our knowledge no models on NH3 emission incorporate the effect of crop and crop height in the calculation of NH3 emission from trailing hose/shoe applied slurry. ...
... Data were obtained from field studies of NH3 emission from livestock slurry applied to cropped and bare soil. (Sommer et al., 1997;Sommer et al., 2000;Misselbrook et al., 2002;Misselbrook et al., 1996;Rodhe and Johanson, 1996). ...
... Several mechanistic volatilization models have been built for ammonia volatilization after slurry application, a.o. by Van der Molen et al. (1990), Wu et al. (2003), Génermont and Cellier (1997; Volt'Air model), Sommer and Olesen (2000) and Beuning et al. (2008;AGRIN model). They were developed so as to find a middle road between the two types of models presented above, the agronomic ones and the SVAT ones. ...
... In fact, the results of the simulations mean that the Volt'air calculations represent well the fact that the ammoniacal N in the soil contributes relatively little to the volatilization of ammonia, compared with the contribution of slurry left on top of the soil. Consequently, correct modelling of the volatilization at the interface of slurry and air is of great importance for the ability to predict volatilization, as was also reported by Sommer and Olesen (2000), Sommer et al. (2003) and Garcia et al. (2012). ...
The high variability of the total ammonia emission after manure application on agricultural land in the Netherlands can partly be linked to the application method, slurry characteristics and the meteorological conditions by statistical analysis of experimental results. Mechanistic models may improve the explanation of the high variability and better reveal the role of certain factors in the volatilization process provided that the simulated results agree well with field results. The performance of the French model Volt’air for simulation of NH3 volatilization from field-applied manure was explored for the conditions of manure, soil, weather that occurred in a number of Dutch field experiments. First results showed that the simulated ammonia emission after surface spreading on bare soil agreed reasonably well with measured values in some field experiments. Simulated trends in effects of soil type, incorporation of the manure, air temperature, rain after application on the total emission were generally as expected from the field experiments, but very high initial NH3 fluxes were simulated compared with measured values. Further development of the model and analysis of the effect of various factors on the emission is recommended to improve the fit of simulated and measured emissions.
... Therefore, increasing the height of the canopy section will increase the resistance to emission in the laminar boundary air layer and reduce emissions (Smith & Watts, 1994;Saha et al., 2011); changing the height of the canopy may affect the measured emission more than changing the air flow through the canopy from 0.1 to 0.6 m/s (Saha et al., 2011). The air flow pattern affects NH 3 emission through its influence on the resistance to transfer in the air layers immediately above the emitting surface, as related to release, transport and exchange processes at the interface between air and the source surface (van der Molen et al., 1990;Sommer & Olesen, 2000). The Henry's constant for the NH 3 (liquid)/ NH 3 (gas) equilibrium does not favour resistance to transport in one of the two phases (Liss & Slater, 1974;Hudson & Ayoko, 2008;Parker et al., 2010). ...
... Considering the release and emission of NH 3 at a wind speed above a certain level (related to surface roughness) (NH 3 (g) is ammonia concentration in the air just above the liquid surface and NH 3,a is ambient ammonia concentration), the aerodynamic (r a, s/m) and the laminar air (r b, s/m) resistances are low compared with the interfacial resistance (r c, s/m). In a study measuring emission with the IHF technique at wind speeds between 1.6 and 4.1 m/s, Sommer & Olesen (2000) concluded that 'the resistance of the laminar air boundary (r b ) is always considerably smaller than the other resistances and less variable. The surface and crop canopy resistance (r c ) is generally the largest of the three resistance terms and also less variable than the aerodynamic resistance (r a )'. ...
Ammonia (NH3) emission from livestock manure constitutes a loss of crop-available nitrogen (N) and poses a threat to the environment. Therefore, low NH3 emission slurry application technologies have been developed, the reduction efficiency of which has typically been estimated through measurements using wind tunnels or integrated horizontal flux (IHF) micrometeorological techniques. A recovery of 100% of released NH3 can be obtained if wind tunnels are designed to avoid pulses of wind into the tunnel through the canopy opening and leaks from the tunnels. The NH3 emission measured with wind tunnels adjusted to an air flow of 1 m/s deviated significantly (P < 0.05) from the emission measured using IHF methods, which are generally considered to give reliable emission estimates for ambient conditions. If wind tunnel air flow was adjusted to the ambient wind speed at height 0.25–0.30 m, then measured emissions were not significantly different from those measured using IHF methods. Wind tunnels influence the air flow pattern and cause turbulent convection in the air layers above the emitting surface, so the similarity in measured emissions for the two measuring techniques is perhaps surprising. This may be because the soil surface resistance to NH3 transport is often the most important rate-regulating variable, so that the absence of a laminar boundary air layer resistance as caused by wind tunnels is of minor importance. It is concluded that the wind tunnels are well suited to test the emission reduction efficiency of new technologies.
... Smith et al. 2009, Ni et al. 2012. Similarly, the calculations by Sommer and Olesen (2000) indicate that slurry application early in the morning or the evening can considerably reduce ammonia emissions compared to application at midday. The results of Rana and Mastrorilli (1998) also show that a substantial proportion of ammonia is emitted around midday. ...
Chemical additives can reduce ammonia emissions from ammonium-containing fertilisers. We aimed to investigate the effect of an additive based on carboxylic acid derivatives on ammonia emissions from slurry. In
a randomised multi-plot field trial, three slurry treatments with increasing amounts of the additive based on carbo-
xylic acid derivates were tested in comparison to untreated slurry and mineral fertiliser. Ammonia emissions were measured with so-called passive samplers, a method already used in numerous studies. However, problems arose during the evaluation of the collected data, so we examined the methodology used in more detail. The results of the measurements were analysed with regard to their spatial distribution and temporal variation. The results show that the more additives were used, the less ammonia was emitted, up to an emission reduction of 48% at the highest additive application rate. However, the spatial distribution of ammonia emissions reveals a drift of ammonia and, thus, an interaction between the plots. Thus, even in unfertilised plots, ammonia emissions of up to 50% of the treatment with the highest emissions were determined. Furthermore, it was also proven that the different times at which the slurry was applied influenced the level of ammonia emissions. Due to the interaction between the plots and the temporal differences in the application of the slurry, measuring ammonia emissions with passive samplers in multi-plot field trials, as presented in this study, is not suitable to quantify differences between the ammonia emissions from different treatments. Based on these results, recommendations for the use of passive samplers to measure ammonia emissions in field trials are proposed.
... For instance, Dowling (2012) reported appreciable reductions in EFs after evening spreading of slurry relative to daytime spreading under Irish conditions, irrespective of the slurry application method (splashplate and trailing shoe). Similarly, studies conducted in France and Denmark show that slurry application between evening and early morning has the potential to reduce emissions by up to 50% (Moal et al., 1995;Sommer & Olesen, 2000). The lower reductions after evening spreading relative to daytime spreading can be attributed to factors such as higher humidity, lower temperatures and lower wind velocity at night. ...
Ammonia (NH 3 ) emissions from livestock production contribute to environmental pollution. To address this challenge, the European Union (EU) National Emission Reduction Commitments Directive 2016/2284 (NECD) sets NH 3 reduction targets for EU member states. In order to achieve these targets, several strategies have been evaluated under Irish conditions. A compilation of emission factors (EFs) from studies which evaluated these strategies is necessary to assess their effectiveness. This paper reports NH 3 EFs from cattle production under Irish conditions. The results from the review show that the mean EFs from the deposition of dung, urine and urea applied to urine patches on grasslands were 4%, 9% and 8% total nitrogen (TN), respectively. EFs from the application of urea to urine patches were reduced by 28% after the addition of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) to urea. The mean EF of 28% TN reported for urea fertiliser was almost 7 times higher than calcium ammonium nitrate (CAN). The inclusion of urease inhibitors with urea fertilisation on grassland led to EF reduction of up to 86%. The mean EFs from cattle houses, concrete yards, slurry storage pits and slurry landspreading were approximately 13%, 35%, 60% and 59% total ammoniacal nitrogen (TAN), respectively. The most effective NH 3 abatement strategies for concrete yards and slurry storage were immediate cleaning of concrete floors (up to 89% reduction) after excreta deposition and the application of chemical amendments (sulphuric acid, acetic acid, alum and ferric chloride) to slurry in storage pits (up to 98% reduction), respectively. Low-emission spreading strategies and slurry acidification were effective at abating EFs after slurry application to land.
... This background-adjusted NH 3 concentration is then used to calculate NH 3 -N raw fluxes. Subsequently, the raw flux is adjusted for the wind speed at the time of measurement by an empirical formula since the wind would affect actual in-field NH 3 emissions [29,30], but the chamber system inhibits those effects [19]. Two empirical formulas were developed for different canopy heights [19]. ...
Easy and inexpensive methods for measuring ammonia emissions in multi-plot field trials allow the comparison of several treatments with liquid manure application. One approach that might be suitable under these conditions is the dynamic tube method (DTM). Applying the DTM, a mobile chamber system is placed on the soil surface, and the air volume within is exchanged at a constant rate for approx. 90 s. with an automated pump. This procedure is assumed to achieve an equilibrium ammonia concentration within the system. Subsequently, a measurement is performed using an ammonia-sensitive detector tube. Ammonia fluxes are calculated based on an empirical model that also takes into account the background ammonia concentration measured on unfertilized control plots. Between measurements on different plots, the chamber system is flushed with ambient air and cleaned with paper towels to minimize contamination with ammonia. The aim of this study was to determine important prerequisites and boundary conditions for the application of the DTM. We conducted a laboratory experiment to test if the ammonia concentration remains stable while performing a measurement. Furthermore, we investigated the cleaning procedure and the effect of potential ammonia carryover on cumulated emissions under field conditions following liquid manure application. The laboratory experiment indicated that the premeasurement phase to ensure a constant ammonia concentration is not sufficient. The concentration only stabilized after performing more than 100 pump strokes, with 20 pump strokes (lasting approximately 90 s) being the recommendation. However, the duration of performing a measurement can vary substantially, and linear conversion accounts for those differences, so a stable concentration is mandatory. Further experiments showed that the cleaning procedure is not sufficient under field conditions. Thirty minutes after performing measurements on high emitting plots, which resulted in an ammonia concentration of approx. 10 ppm in the chamber, we detected a residual concentration of 2 ppm. This contamination may affect measurements on plots with liquid manure application as well as on untreated control plots. In a field experiment with trailing hose application of liquid manure, we subsequently demonstrated that the calculation of cumulative ammonia emissions can vary by a factor of three, depending on the degree of chamber system contamination when measuring control plots. When the ammonia background values were determined by an uncontaminated chamber system that was used to measure only control plots, cumulative ammonia emissions were approximately 9 kg NH3-N ha−1. However, when ammonia background values were determined using the contaminated chamber system that was also used to measure on plots with liquid manure application, the calculation of cumulative ammonia losses indicated approximately 3 kg NH3-N ha−1. Based on these results, it can be concluded that a new empirical DTM calibration is needed for multi-plot field experiments with high-emitting treatments.
... Those techniques are based either on lowering the pH of the liquid organic fertilizer [27] or on reducing the contact area of the applied organic fertilizer with the atmosphere. The application by trailing shoe [28,29] or direct injection into the soil [30] are two prominent means to reduce the contact area to the atmosphere. Applying organic fertilizers with injection technique is oftentimes combined with the use of a nitrification inhibitor (NI) in order to reduce emission of the greenhouse gas N 2 O [11], as well as nitrate leaching [31]. ...
Ammonia emissions following liquid manure application impair human health and threaten natural ecosystems. In growing arable crops, where immediate soil incorporation of the applied liquid manure is not possible, best-available application techniques are required in order to decrease ammonia losses. We determined ammonia emission, crop yield and nitrogen uptake of winter wheat in eight experimental sites across Germany. Each individual experiment consisted of an unfertilized control (N0), broadcast calcium ammonium nitrate (CAN) application as well as four different techniques to apply cattle slurry (CS) and biogas digestate (BD). Fertilizer was applied to growing winter wheat at a total rate of 170 kg N ha−1 split into two equal dressings. The following application techniques were tested for both liquid manure types: (i) trailing hose (TH) application using untreated and (ii) acidified (~pH 6) liquid manure (+A), as well as (iii) a combination of open slot injection (SI) for the first dressing and trailing shoe (TS) application for the second dressing without and (iv) with the addition of a nitrification inhibitor (NI) for the first dressing. The highest ammonia emissions (on average 30 kg N ha−1) occurred following TH application of BD. TH application of CS led to significantly lower emissions (on average 19 kg N ha−1). Overall, acidification reduced ammonia emissions by 64% compared to TH application without acidification for both types of liquid manures. On average, the combination of SI and TS application resulted in 23% lower NH3 emissions in comparison to TH application (25% for the first application by SI and 20% for the second application by TS). Supplementing an NI did not affect ammonia emissions. However, decreasing ammonia emissions by acidification or SI did not increase winter wheat yield and nitrogen uptake. All organically fertilized treatments led to similar crop yield (approx. 7 t ha−1 grain dry matter yield) and above-ground biomass nitrogen uptake (approx. 150 kg ha−1). Yield (8 t ha−1) and nitrogen uptake (approx. 190 kg ha−1) were significantly higher for the CAN treatment; while for the control, yield (approx. 4.5 t ha−1) and above-ground biomass nitrogen uptake (approx. 90 kg ha−1) were significantly lower. Overall, our results show that reducing NH3 emissions following liquid manure application to growing crops is possible by using different mitigation techniques. For our field trial series, acidification was the technique with the greatest NH3 mitigation potential.
... The organic form of nitrogen present in the wastewater was converted to nitrate (NO 3 − ) under aerobic and anaerobic conditions while ammonia nitrogen (NH 3 -N) was removed via hydrophytes absorption, volatilization, nitrification, and denitrification in the constructed wetland [9,10]. Percentage NH 4 removal of 48.1% for well 4 for the constructed wetland at Worms was in agreement with 41% reported by [5] but significantly lower than 94% reported by [6]. ...
This paper evaluates the performance of a subsurface flow constructed wetland at Worms Germany used for the treatment of black and grey water from a non-residential facility. Snap black water samples from four wells made up of a clarifying unit, an activated carbon unit and an aeration unit were analysed insitu using the HACH HQ40d multimeter and exsitu using Sensafe water metals check strips for preliminary metal detection onsite. HACH bar code reagents, a HACH Digital Reactor Block 200 (DRB200) and a HACH DR 3900 Spectrophotometer were subsequently used for the analysis of lead (Pb), chromium (Cr), cadmium (Cd), biochemical oxygen demand (BOD), Chemical Oxygen demand (COD), Ammonium (NH 4 -N) and Nitrate (NO 3 -N) in the lab. The removal efficiency for the constructed wetland was in the order BOD > Cr > COD > NH 4 -N > NO 3 -N > Pb. The 57.90% removal efficiency of COD for the constructed wetland was due to the higher fractions of inert COD which constitutes a part black water. This makes the use of the BOD/COD ratios of 0.69 and 0.5 for wells 1 and 4 an unreliable index for the determination of amenability of COD in black water with regards to microbial activity at the wetland at Worms. The pH range of 7.2–8.4 of the blackwater is conducive for the growth microbes necessary for the breakdown of organic matter in the black water. Further investigation including plant and sediment analysis over different seasons has to be undertaken if the efficiency of the constructed wetland for nutrients and metals removal is to be optimized.
... Hoses drag across the soil surface, depositing slurry in bands between crop rows, reducing ESA and NH3 volatilization compared to broadcast, full-width spreading [20]. Placing slurry beneath the canopy of a growing crop has also been shown to reduce NH3 emissions [9,21,22] and is, therefore, a method well suited to springtime application in established winter cereals. However, trailing hoses are prone to side-to-side shifting during operation and may bounce on top of the soil, causing some splashing; thus, hoses are not ideal when targeting fertilizer placement in close proximity to crop rows. ...
Ammonia (NH3) emissions resulting from the field application of livestock slurry has both negative human health and environmental impacts. However, decreasing the exposed surface area (ESA) of slurry upon application can reduce NH3 volatilization by limiting its atmospheric exposure. In the present study, three strategies for depositing slurry within a growing crop were studied, including: 1. standard trailing hoses (SAhose), 2. trailing shoes (SAshoes), and 3. the combination of rigid tines and trailing shoes (SAtines+shoes). Application methods interact with the soil to varying degrees and were evaluated within the context of contemporary weed management practices, namely in cereals receiving inter-row hoeing. SAhose, SAshoes, and SAtines+shoes were compared in three coinciding experiments that assessed slurry ESA, NH3 emissions, and crop and weed effects. SAtines+shoes resulted in smallest ESA, 70–72% and 61–66% less than SAhose and SAshoes, respectively. However, in only one of three site–years did SAshoes and SAtines+shoes reduce NH3 emissions compared to SAhose, by 46% and 29%, respectively. Crop yields, nitrogen (N) accumulation in crop biomass, and intra-row weed biomass were unaffected by the placement method. In heavily crusted soils, the SAtines+shoes prototype worked well; however, the functional differences among placement strategies were not great enough to detect crop and NH3 effects.
... As a result, nitrate removal accounted for the majority of total nitrogen (TN) removal. Hydrophytes absorption, volatilization, and nitrification/denitrification were the three primary mechanisms involved in NH3-N removal [15]. Nitrogen is required for optimum plant growth. ...
The constructed wetland (CW) technology for eliminating contaminants from wastewater is environmentally favorable. A one-year pilot study was conducted at ICRISAT in Hyderabad (Telangana) to evaluate the efficacy of subsurface flow-constructed wetlands (SSF-CWs). To treat and evaluate their suitability for irrigation reuse, urban domestic wastewater was continuously fed into non-vegetative and vegetative wetland chambers with combination vegetation of Typhalatifolia & Ageratum conyzoids (CW-T) and Canna indica & Ageratum conyzoids (CW-C) and Control (non-vegetative). For one year, raw wastewater and treated wastewater were collected monthly and analyzed for quality. pH, BOD, COD, Total Solids, Total Suspended Solids, Total Dissolved Solids, Nitrogen, Sulphates, Ammonia, and Phosphorus were all investigated. The concentrations of all parameters are reduced by 60 to 90 percent in this constructed wetland (approx.). Water quality parameters were analyzed using statistical approaches such as principal component analysis (PCA), correlation analysis, time series analysis, and cluster analysis. In this investigation, PCA identified a reduced number of two primary components, showing that 95% of changes affect water quality. The first factor explained 51% of the variance in EC, TDS, COD, Nitrates, and Ammonia. The second factor accounted for 44% of the remaining variance in pH, BOD, Phosphates, and Sulphates. Between EC, TDS, Nitrates, Ammonia, and COD, the dendrogram of physicochemical parameter similarity revealed a maximum similarity of 76.85 percent. The SSF-CWs for the treatment of urban wastewater achieved more than 80% removal efficiency with no running expenses, minimal maintenance costs, enhances the environment, provides a natural habitat for birds, is odor-free, and can be recommended for agricultural use, according to this study.
... Therefore, NH3-N removal mainly contributed to total nitrogen (TN) removal. Three main processes involved in NH3-N removal were: hydrophytes uptake, volatilization and nitrification/denitrification (Sommer, 2000).Total Nitrogen is normally reduced by denitrification, adsorption and incorporation into cell mass (Al-Omari, 2003). Plants need Nitrogen for their growth and reproduction. ...
Land areas which are wet during part or all of the year are referred as wetlands. Constructed wetlands are manmade systems that mimic the functions of natural wetlands and applied for wastewater treatment. Aim of the present study is to investigate the feasibility of using a Tracheophyte, Phragmiteskarka in constructed wetland for treatment of wastewater in an public park. The daily inlet and outlet wastewater physico-chemical parameters were analysed during the period of two months. The parameters studied were pH, BOD, COD, DO, Total Suspended Solids, Total Dissolved Solids, Nitrogen and Phosphorus. The percentage removal of the parameters were analysed and studied until the percent removal rate gets stabilized. The study showed that the subsurface flow constructed wetlands are best alternative among modern treatments.
... Only NH 3 can be emitted from the soil surface into the air and only this form can be detected by the optode. Several theoretical models exist that account for those as well as other chemical and physical processes, but they still fall short of fully predicting the emission of NH 3 (Hafner et al., 2019;Ni, 1999;Sommer and Olesen, 2000); likely due to the problem of accurately modeling local heterogeneities. ...
The application of fertilizers and manure on fields is the largest source of ammonia (NH3) in the atmosphere.·NH3 emission from agriculture has negative environmental consequences and is largely controlled by the chemical microenvironment and the respective biological activity of the soil. While gas phase and bulk measurements can describe the emission on a large scale, those measurements fail to unravel the local processes and spatial heterogeneity at the soil air interface. We report a two dimensional (2D) imaging approach capable of visualizing three of the most important chemical parameters associated with NH3 emission from soil. Besides the released NH3 itself also O2 and pH microenvironments are imaged using reversible optodes in real-time with a spatial resolution of <100 µm. This combined optode approach utilizes a specifically developed NH3 optode with a limit of detection of 2.11 ppm and a large working range (0-1800 ppm) ideally suited for studying NH3 volatilization from soil. This NH3 optode will contribute to a better understanding of the driving factors for NH3 emission on a microscale and has the potential to become a valuable tool in studying NH3 dynamics.
... This phenomenon causes the effect of increasing the surface area of liquid fertilizer and air, thereby increasing the ammonia emission flux [36]. With this in mind, liquid fertilizer applications that can reduce ammonia emissions have been studied through the use of crop height, adjustment of viscosity, timing of application, injection, and more [36][37][38]. In this section, washed and dried GWS was used, and the initial water content was not considered, and so there is a limit to continuously using 5 cm. ...
This study was conducted with the aim of improving the dynamic camber-capture system, which estimates ammonia emissions during the application of liquid fertilizer from livestock manure. We focused on the volume of the chamber and headspace, the height of the solid media, the flow rate of the pump, and the ventilation rate. Total ammoniacal nitrogen (NH3 + NH4 +) is an important factor affecting ammonia volatilization. Even though the characteristics of liquid fertilizer were changed, the effect of total ammoniacal nitrogen on ammonia volatilization remained the largest. Increasing the thickness of solid media inside the chamber has the effect of reducing ammonia emission by reducing the contact area between liquid fertilizer and air. Although it is very difficult to measure and control the wind velocity in a chamber using a general vacuum pump, it can be indirectly evaluated through the ventilation rate in the macroscopic aspect. The higher the ventilation rate, the faster the flow of air in the chamber, which is linear with the increase in ammonia emission flux. We find that it may be necessary to improve the steady wind velocity within the chamber and of the linkages to upscale the wind tunnel system.
... In both years, application dependent NH 3 volatilization showed the same trends, whereas the extent of the gaseous NH 3 losses was strongly regulated by environmental factors. The strong effect of environmental factors on NH 3 release has also been reported by Mattila (2006), Sommer et al. (2003), Sommer and Hutchings (2001), and Sommer and Olesen (2000). Thus, the comparison of management effects on NH 3 volatilization between different studies may become difficult if environmental conditions are not comparable. ...
We determined N2O fluxes from an unfertilized control (CON), from a treatment with mineral N‐fertilizer (MIN), from cattle slurry with banded surface application and subsequent incorporation (INC), and from slurry injection (INJ) to silage maize (Zea mays, L.) on a Haplic Luvisol in southwest Germany. In both years, amount of available N (total N fertilized + Nmin content before N application) was 210 kg N ha−1. In the slurry treatment of the 1st year, 140 kg N ha−1 were either injected or incorporated, whereas 30 kg N ha−1 were surface applied to avoid destruction of the maize plants. In the 2nd year, all fertilizers were applied with one single application. We calculated greenhouse gas emissions (GHG) on field level including direct N2O emissions (calculated from the measured flux rates), indirect N2O emissions (NH3 and NO3 - induced N2O emission), net CH4 fluxes, fuel consumption and pre‐chain emissions from mineral fertilizer. NH3 losses were measured in the 2nd year using the Dräger‐Tube Method and estimated for both years. NH3 emission was highest in the treatment without incorporation. It generally contributed less than 5% of the greenhouse gas (GHG) emission from silage maize cultivation. The mean area‐related N2O emission, determined with the closed chamber method was 2.8, 4.7, 4.4 and 13.8 kg N2O‐N ha−1 y−1 for CON, MIN, INC, and INJ, respectively. Yield‐related N2O emission showed the same trend. Across all treatments, direct N2O emission was the major contributor to GHG with an average of 79%. Trail hose application with immediate incorporation was found to be the optimum management practice for livestock farmers in our study region.
... As such, most of the losses in urea and UAN treated with inhibitor in the field study would have been avoided by the rain event, whereas the losses from the untreated urea and UAN would still be large, as much of the volatilization occurred before the rainfall event. In addition, under field condition without a chamber, the canopy from canola leaves may provide conditions that would reduce ammonia volatilization from unhydrolyzed urea during the later days of sampling (Sommer and Olesen 2000). However, this would not have any effect on ammonia volatilization from untreated urea as most of the losses had occurred before the leaves were large enough to provide such canopy. ...
N-(n-Butyl)thiophosphoric triamide (NBPT) has been reported to reduce ammonia volatilization from surface-applied urea and urea ammonium nitrate (UAN). A new NBPT formulation (ARM U™, 18% NBPT) that contains a polymer allowing for lower application rate of NBPT was evaluated for its efficacy relative to Agrotain ® (30% NBPT) and Arborite ® (24% NBPT). Trials consisted of (i) a greenhouse study that compared two rates of ARM U-treated urea (360 and 540 mg NBPT kg ⁻¹ urea) with Arborite- or Agrotain-treated urea (480 and 600 mg NBPT kg ⁻¹ urea, respectively) and (ii) a field study that compared urea and UAN treated with either ARM U (360 mg NBPT kg ⁻¹ urea) or Agrotain (600 mg NBPT kg ⁻¹ urea) at two sites. Static chambers fitted with acid-charged discs were used to measure ammonia volatilization at six or seven dates over 28 d. In the greenhouse study, ammonia volatilization was reduced by 96% with either ARM U or Agrotain and 95% with Arborite. In the field study, ARM U and Agrotain reduced ammonia volatilization from urea by 80% and 66%, respectively, across sites. Similarly, ammonia volatilization from UAN was reduced by 46% and 60% with ARM U and Agrotain, respectively. Despite the lower NBPT application rates with ARM U, ammonia reduction by ARM U, Agrotain, and Arborite was not significantly different. The addition of ARM U to urea and UAN enabled lower application rate of NBPT without compromising its efficacy.
... Models for predicting NH 3 emission can be used to assess mitigation strategies, develop emission inventories, and optimize field application of manure and other fertilizers. In the last two decades, several models have been developed to predict NH 3 emission from manure applied to fields (Braschkat et al., 1997;Genermont and Cellier, 1997;Menzi et al., 1998;Sommer and Olesen, 2000;Søgaard et al., 2002;Misselbrook et al., 2005;Smith et al., 2009;Gericke et al., 2012;Congreves et al., 2016). Many of these models are process-based or mechanistic, meaning that emission rate is based on a mathematical representation of relatively low-level physical or chemical processes (Cuddington et al., 2013). ...
This work describes a semi-empirical dynamic model for predicting ammonia volatilization from field-applied slurry. Total volatilization is the sum of first-order transfer from two pools: a "fast" pool representing slurry in direct contact with the atmosphere, and a "slow" one representing fractions less available for emission due to infiltration or other processes. This simple structure is sufficient for reproducing the characteristic course of emission over time. Values for parameters that quantify effects of the following predictor variables on partitioning and transfer rates were estimated from a large data set of emission from cattle and pig slurry (490 field plots in 6 countries from the ALFAM2 database): slurry dry matter, application method, application rate, incorporation (shallow or deep), air temperature, wind speed, and rainfall rate. The effects of acidification were estimated using a smaller dataset. Model predictions generally matched the measured course of emission over time in a reserved data subset used for evaluation , although the model over-or underestimated emission for many individual plots. Mean error was ca. 12% of applied total ammoniacal nitrogen (and as much as 82% of measured emission) for 72 h cumulative emission, and model efficiency (fraction of observed variation explained by the model) was 0.5-0.7. Most of the explanatory power of the model was related to application method. The magnitude and sign of (apparent) model error varied among countries, highlighting the need to understand why measured emission varies among locations. The new model may be a useful tool for predicting fertilizer efficiency of field-applied slurries, assessing emission factors, and quantifying the impact of mitigation. The model can readily be applied or extended, and is available as an R package (ALFAM2, https://github.com/sashahafner/ALFAM2) or a simple spreadsheet (http://www.alfam.dk).
... For the control bioreactor at 40°C, since no NO 2 − or NO 3 − was observed, the decrease of NH 4 + concentrations could probably be attributed to total loss of ammonium in the form of ammonia gas. In fact, as the temperature rises, the rate of NH 3 volatilization increases significantly (Fan et al., 2011;Sommer and Olesen, 2000). However, the possibility of ammonium immobilization could not be ruled out. ...
Aquaculture has experienced a burgeoning growth worldwide in the last decade resulting in nearly 50% of seafood originating from aquaculture farms. However, there are less studies on the utilization of the manure produced by aquatic organisms in comparison to warm-blooded livestock. Aquaponics offers more efficient utilization of nutrients and can reduce the operational costs in aquaculture. This paper presents the results of a study to identify the optimal settings to digest fish manure through a microbial-assisted aerobic bioprocess, using endogenous heterotrophic and nitrifying bacteria. The effects of pH (5.5, 6.0 and 6.5), temperature (30, 35 and 40 °C) and duration (1–30 days) on kinetics of nitrogen mineralization were investigated and compared to a control bioreactor (carried out without pH adjustment). The mineralization dynamics for all pH-controlled bioreactors revealed that only ammonification occurred. No nitrification was observed for all three-temperature conditions and throughout the entire bioprocessing period. The mineralization process in the control bioreactor, on the other hand, followed the typical non-inhibited nitrogen mineralization (i.e., release of ammonium followed by oxidation into nitrate). However, nitrate was only observed at temperatures <40 °C indicating a complete suppression of nitrification at higher temperatures. Analytical data and modeled parameters indicated that the bioprocessing of aquaculture solid waste for 15 days at 35 °C using either pH 6.0 or 6.5 maximized nitrogen bioconversion in the form of ammonium ions (NH4⁺). This study indicates the importance of temperature and pH optimization for more efficient processing of aquaculture solid waste such as fish manure.
... On the other hand, an exceptionally high value of the measured emissions is unlikely because a rainfall event started during the second half of the grazing period and lasted almost 2 days with a precipitation amount of about 40 mm (data not shown). Typically, smaller volatilisation of NH 3 is expected during such weather periods (Sommer and Olesen, 2000). A delayed onset of emissions was observed as described in Móring et al. (2016) after the rain event stopped. ...
The quantification of ammonia (NH3) emissions is still a challenge and the corresponding emission factor for grazed pastures is uncertain. This study presents NH3 emission measurements of two pasture systems in western Switzerland over the entire grazing season 2016. During the measurement campaign, each pasture system was grazed by 12 dairy cows in an intensive rotational management. The cow herds on the two pastures differed in the energy to protein balance of the diet. NH3 concentrations were measured upwind and downwind of a grazed subplot with line-integrating open path instruments that were able to retrieve small horizontal concentration differences (< 0.2 µg NH3 m-3). The NH3 emission fluxes were calculated by applying a backward Lagrangian stochastic (bLS) dispersion model to the difference of paired concentration measurements and ranged from 0 to 2.5 µg N–NH3 m-2 s-1. The fluxes increased steadily during a grazing interval from previous non-significant values to reach maximum emissions at the end of the grazing interval. Afterwards they decreased exponentially to near zero-values within 3–5 days. A default emission curve was calculated for each of the two systems and adopted to each rotation in order to account for missing data values and to estimate inflow disturbances due to grazing on upwind paddocks. Dung and cow location were monitored to account for the non-negligible inhomogeneity of cow excreta on the pasture. The average emission (± SD of individual rotation values) per grazing hour was calculated as 0.64±0.11 g N–NH3 cow-1 h-1 for the herd with the N-balanced diet (system M) and 1.07±0.06 g N–NH3 cow-1 h-1 for the herd with the protein-rich grass-only diet (system G). Surveys of feed intake, body weight and milk yield of the cow herds were used to estimate the nitrogen (N) excretion by an animal N budget model. Based on that, mean relative emission factors of 6.4±2.0 % and 8.7±2.7 % of the applied urine N were found for the systems M and G, respectively. The results can be used to validate the Swiss national emission inventory and demonstrate the positive effect of an N-balanced diet on pasture NH3 emissions.
... Organic nitrogen and ammonia nitrogen (NH 3 -N) represent the main type of nitrogen in wastewater [35]. The decreasing of Nt values result from: hydrophytes uptake, volatilization and nitrification-denitrification [41,36]. Lavrova and Koumanova [37] found that the fully removal of the ammonium-nitrogen was achieved for twelve days using lab-scale subsurface vertical-flow wetland. ...
Removal of wastewater pollution by natural treatment systems such as wetlands is achieved using filter media and macrophytes plants. The functioning of constructed wetlands relies on physical, chemical and biological processes. The aim of the present study is to evaluate the performance of the Phragmites australis for domestic wastewater treatment under an arid climate. Experiments were conducted during three months (February, March and April). Results indicate that the variation of pH values of raw and treated wastewater is not significant. The electrical conductivity increases strongly during March and April. It was also found that dissolved oxygen in planted filter exceeds that of the unplanted one. Also, the higher performance in BOD and Ntot removal by the planted filter confirms the important role of this plant in the treatment process.
... The non-linear model of Sommer and Olesen (2000;also Sommer et al. 2003), which utilises this temperature-difference relationship, may be applicable in generalising from one site to another for the effect of temperature on NH 3 emission where the environmental and physical factors may fall outside of those at this site. This could be the case, for example, where wind speed, friction velocity and other factors determine the slope and shape of the temperature-difference relationship with emission. ...
The nitrogen (N) excreted at intensive livestock operations is vulnerable to volatilisation, and, subsequently, may form a source of indirect nitrous oxide (N2O) emissions. The present study simultaneously investigated volatilisation and deposition of N at a beef feedlot, semi-continuously over a 129-day period. These data were examined relative to pen manure parameters, management statistics and emission-inventory calculation protocols. Volatilisation measurements were conducted using a single, heated air-sampling inlet, centrally located in a feedlot pen area, with real time concentration analysis via cavity ring-down spectroscopy and backward Lagrangian stochastic (bLS) modelling. Net deposited mineral-N was determined via two transects of soil-deposition traps, with samples collected and re-deployed every 2 weeks. Total volatilised ammonia amounted to 210 tonnes of NH3-N (127 g/animal.day), suggesting that the inventory volatilisation factor probably underestimated volatilisation in this case (inventory, 30% of excreted N; 65 g N volatilised/animal.day; a value of ~60% of excreted N is indicated). Temperature contrast between the manure and air was observed to play a significant role in the rate of emission (R² = 0.38; 0.46 Kendall’s tau; P < 0.05). Net deposition within 600 m of the pen boundary represented only 1.7% to 3% of volatilised NH4⁺-N, between 3.6 and 6.7 tonnes N. Beyond this distance, deposition approached background rates (~0.4 kg N/ha.year).
... Process-based models attempt to replicate the effects of meteorology on the formation of NH 3 from an N r source. NH 3 volatilization has been shown to increase at both high temperatures and high wind speeds (Demmers et al., 1998;Sommer and Christensen, 1991), while rain events may cause NH 3 emissions to drop to almost zero, as illustrated by Sommer and Olesen (2000) for liquid manure spreading in Denmark. Most recent models calculate NH 3 fluxes using Henry's Law, i.e. the dissociation reactions of ammonium and NH 3 in solution is used to calculate the NH 3 gas on the surface, with the flux estimated using a resistance-based approach (e.g. ...
Many studies in recent years have highlighted the ecological implications of adding reactive nitrogen (Nr) to terrestrial ecosystems. Seabird colonies represent a situation with concentrated sources of Nr, through excreted and accumulated guano, often occurring in otherwise nutrient-poor areas. To date, there has been little attention given to modelling N flows in this context, and particularly to quantifying the relationship between ammonia (NH3) emissions and meteorology. This paper presents a dynamic mass-flow model (GUANO) that simulates temporal variations in NH3 emissions from seabird guano. While the focus is on NH3 emissions, the model necessarily also treats the interaction with wash-off as far as this affects NH3. The model is validated using NH3 emissions measurements from seabird colonies across a range of climates, from sub-polar to tropical. In simulations for hourly time-resolved data, the model is able to capture the observed dependence of NH3 emission on environmental variables. With temperature and wind speed having the greatest effects on emission for the cases considered. In comparison with empirical data, the percentage of excreted nitrogen that volatilizes as NH3 is found to range from 2% to 67% (based on measurements), with the GUANO model providing a range of 2%–82%. The model provides a tool that can be used to investigate the meteorological dependence of NH3 emissions from seabird guano and provides a starting point to refine models of NH3 emissions from other sources.
... comparing initial fluxes, and to apply and develop process oriented models (e.g. van der Molen et al., 1990;Hutchings al., 1996;Génermont and Cellier, 1997;Sommer and Olesen, 2000;Beuning et al., 2008). The present assessment signifies that current emission inventories likely need to be updated including the findings of the new generation of field scale NH 3 emission measurements. ...
The EMEP/EEA guidebook 2009 for agricultural emission inventories reports average ammonia (NH3) emission factors (EF) by volatilisation of 55% of the applied total ammoniacal nitrogen (TAN) content for cattle slurry, and 35% losses for pig slurry, irrespective of the type of surface or slurry characteristics such as dry matter content and pH. In this review article, we compiled over 350 measurements of EFs published between 1991 and 2011. The standard slurry application technique during the early years of this period, when a large number of measurements were made, was spreading by splash plate, and as a result reference EFs given in many European inventories are predominantly based on this technique. However, slurry application practices have evolved since then, while there has also been a shift in measurement techniques and investigated plot sizes. We therefore classified the available measurements according to the flux measurement technique, measurement plot size, the year of measurement, and the year of publication. Medium size plots (usually circles between 20 to 50 m radius) generally yielded the highest EFs. The most commonly used measurement setups at this scale were based on the Integrated Horizontal Flux method (IHF or the ZINST method (a simplified IHF method)). Several empirical models were published in the years 1993 to 2003 predicting NH3 EFs as a function of meteorology and slurry characteristics (Menzi et al., 1998; Søgaard et al., 2002). More recent measurements that appeared subsequently show substantially lower EFs, and appear to indicate a need for a revision of the EF in emission inventories.
... In these studies, the oasis effect has been quantified using resistance and advection models for situations in which animal slurry was applied to land. A resistance framework can be used to model vertical transfer through the laminar and atmospheric boundary layers (Monteith and Unsworth 1990) and has been adapted for use with NH 3 by Sommer and Olesen (2000). Unlike a 1-D resistance model, an advection model incorporates height and distance from the edge of the field (e.g., Loubet et al. 2001). ...
The validity of emission factors derived from small-scale measurements of ammonia (NH3) volatilization has been questioned in the literature because gaseous NH3 concentration gradients differ at the edge of the measurement plot and may result in higher emissions than at field scale. We studied this "oasis effect" using two very long (22 m) wind tunnels constructed indoors over soil plots fertilized with surface-applied urea (20 g N m⁻²). We hypothesized that NH3 flux would be highest at the start of the tunnel and decrease with distance. Air NH3 concentration was measured every 2 m along each tunnel for 2 wk after urea application; NH3 flux did not decrease along the length of the tunnels. Of the 60 measurement periods, when there was significant NH3 volatilization, only two had a significant nonlinear relationship (P ≤ 0.05) between NH3 concentration and distance. For the other periods, the NH3 concentration increased linearly with distance (P ≤ 0.05). The background NH3 concentration difference between halves of the tunnels was not significantly related to NH3 flux difference (P > 0.1). Our results indicate that wind tunnel measurements of NH3 volatilization fertilized using urea are not impacted by a measurable oasis effect.
... This is consistent with the findings from previous studies (e.g. Sommer and Olesen, 2000) and can be explained by the higher NH 3 emission potential at noon (Spirig et al., 2010) in combination with the high fraction of total loss occurring soon after application. ...
Loss of ammonia (NH3) after field application of livestock slurry contributes between 30% and 50% of agricultural NH3 emissions from European countries. The objectives of this study were to re-evaluate NH3 emissions following application of cattle and pig slurry to grassland in Switzerland and to investigate the effectiveness of abatement techniques. In 17 field experiments, NH3 emissions were determined with a micrometeorological approach, relating the emission to the measured concentration by means of atmospheric dispersion modelling. The cattle slurry applied exhibited an average dry matter content of 3.3% (range between 1.0% and 6.7% dry matter). The emission after application of cattle slurry spread with a splash plate (referred to as reference technique) ranged from 10% to 47% of applied Total Ammoniacal Nitrogen (% of TAN) and averaged to 25% of TAN. This range of losses is lower by approx. a factor of two compared to measurements from earlier Swiss experiments. Applications with trailing hose and trailing shoe systems yielded an average reduction of 51% and 53%, respectively, relative to the reference technique. A regression analysis showed that the dry matter content of the slurry and the air temperature are important drivers for NH3 emission.
... 9 Fig. 6Fig. 7 and nitrification/denitrification (Sommer, 2000). Total Nitrogen is normally reduced by denitrification, adsorption and incorporation into cell mass (Al-Omari, 2003). ...
... As a consequence, slurry injection, and to a lesser extent, harrowing after slurry application is expected to reduce NH 3 loss, owing to the limited contact of the slurry with the atmosphere. Similarly, band spreading should reduce ammonia volatilization compared to broadcast spreading due to a reduced air/slurry contact area, along with other factors described in Sommer & Olesen [2000]. ...
The general objective of the thesis is to develop and validate an assessment framework of the environmental efficiency of slurry application techniques based on Life Cycle Assessment (LCA). A first LCA showed that the impact of the manufacturing and the use of slurry spreaders were negligible compared to those induced by the nitrogenous emissions (NH3, N2O & NO3-) from the fertilized soil. These emissions depend on soil, climate and agricultural practices and are thus eminently site-specific. This is challenging for LCA, which is a method based on the absence of spatial differentiation. To account for the variability of nitrogenous emissions at field level in the LCA of the slurry application function, two approaches were followed: (A) by using experimental data from the literature which allowed to order four application techniques in a robust way, to quantify the variability of emissions and to discuss the uncertainty induced on LCA final results. (B) by using simulated data with models from soil physics, agro-climatology, and agronomy models. A coherent simulation tool was developed including the effects on nitrogenous emissions from i) the incorporation of slurry into the soil, ii) the soil compaction by the spreaders, iii) the spatial distribution of the slurry over the field. These effects were simulated in 5 sites in France over 7 years. The range of emissions for each technique estimated with both approaches was comparable. The use of models allowed to assess the contribution of each elementary effect on nitrogenous emissions and to order the applications techniques in a range of contrasted situations. Finally, a general methodology for the inclusion of variability in the environmental inventory for agricultural products is proposed.
... Er gyllesprederen ubemandet, kan gyllen evt. udbringes om natten, hvorved ammoniaktabet reduceres med 50-60% i forhold til udkørsel om dagen (Sommer & Olesen, 2000), og lugtgenerne mindskes. ...
... Therefore, NH 3 -N removal mainly contributed to total nitrogen (TN) removal. Three main processes involved in NH 3 -N removal were: hydrophytes uptake, volatilization Universal Journal of Environmental Research and Technology and nitrification/denitrification (Sommer, 2000). Total Nitrogen is normally reduced by denitrification, adsorption and incorporation into cell mass (Al-Omari, 2003). ...
Performance Evaluation of Surface Flow Constructed Wetland System by Using Eichhornia crassipes for Wastewater Treatment in an Institutional Complex
... The slurry dry matter content has been shown to be an important factor in determining the NH 3 emission potential. Sommer and Olesen (2000) showed a linear relationship between cattle slurry dry matter content and NH 3 emission in the range 4-12 % DM, but outside this range dry matter had a little effect on NH 3 emission. Smith et al. (2000) reported a similar linear relationship but in a shorter range (2-5 % of slurry dry matter) and concluded that for every 1 % increase in slurry dry matter, NH 3 losses increased about 6 %. ...
... Temperature as such has not always proven an important factor in determining NH 3 volatilization from applied manure (e.g. Braschkat et al. 1997, Sommer and Olesen 2000, Misselbrook et al. 2005a). ...
As the livestock numbers on Finnish dairy farms have increased and most fields on dairy farms are under grass, it has become common to spread cattle slurry over grasslands. To estimate environmental effects of recurrent slurry applications, a 5-year field study was performed to compare nitrogen (N) losses to water and ammonia losses to air by volatilization, when cattle slurry was either surface broadcast or injected into clay soil after grass cuttings. Slurry was spread on the grass in summer (1996-1997) or both in summer and autumn (1998-2000). Biomass N uptake before grass harvesting and amount of soil mineral N in spring and autumn were measured and field N balances were calculated. Despite cool weather, up to one third of the ammonium N of broadcast slurries was lost through ammonia volatilization after application in autumn, but injection effectively prevented losses. The mean surface runoff losses of total N were negligible (0.3-4.6 kg ha-1 yr-1) with the highest loss of 13 kg ha-1 yr-1 measured after slurry broadcasting to wet soil in autumn and followed with heavy rains. A substantial part (24-55%) of the applied mineral N was not recovered by the foregoing measurements.
... The slurry dry matter content has been shown to be an important factor in determining the NH 3 emission potential. Sommer and Olesen (2000) showed a linear relationship between cattle slurry dry matter content and NH 3 emission in the range 4-12 % DM, but outside this range dry matter had a little effect on NH 3 emission. Smith et al. (2000) reported a similar linear relationship but in a shorter range (2-5 % of slurry dry matter) and concluded that for every 1 % increase in slurry dry matter, NH 3 losses increased about 6 %. ...
Background Application of different chemical fertilizers and manures is a major source of ammonia (NH3) emission. The rate and total amount of NH3 emission are related to different parameters such as climatic conditions, soil characteristics and kind of fertilizer. The current study has indicated the NH3 emission from bovine slurry, pig slurry and ammonium nitrate fertilizer after application on two soils. Two different methods were used to measure NH3 emissions: the method that use acid traps and the method that use photoacoustic infrared gas analyzer. Results In both soils the rate of NH3 emission was the greatest from the denser bovine slurry, declined in the pig slurry followed by the ammonium nitrate treatment and the control. The rate of soil infiltration could be the main factor that explained these differences. For all treatments the amount of total NH3 losses reduced in the more acidic soil. For all fertilizers the highest NH3 fluxes were measured in the first hours after spreading. A good agreement observed between the two methods is used for determining of NH3 emission. The use of a multi-gas monitor (MGM) is simple and accurate and produces a continuous series of NH3 concentration in time. Conclusion The rate and amount of NH3 emission was related to the kind of fertilizers and interaction of these treatments with soils. The results of current study confirmed that comparison of chemical fertilizers and slurry for NH3 emission is difficult because the reaction of these two groups of fertilizer is totally different.
The use of digestate in agriculture represents an opportunity for reducing the use of synthetic fertilizers while promoting nutrient and organic matter recycling, i.e. contributing to a circular economy. However, some environmental impacts could result from digestate use, with particular reference to N emissions, which can contribute to particulate matter formation in the atmosphere. So, correct digestate spreading methods need to be tested to reduce ammonia emission and, possibly, also to avoid annoyance to the inhabitants. In this work a digestate from organic wastes was used as a fertilizer by its injection at 15 cm, in comparison with a synthetic one (urea) for three consecutive years in open fields, measuring ammonia and odours emission. On average, the ammonia emission from digestate was of 25.6 ± 9.4 kg N Ha⁻¹ (11.6% ± 4 of Total Ammonia Nitrogen - TAN - dosed), while urea emitted 24.8 ± 8.3 kg N Ha⁻¹ (13.4% ± 4.5 of TAN dosed). The injected digestate also emitted less odour than urea (601 ± 531 and 1767 ± 2221 OU m⁻² h⁻¹, respectively), being ammonia coming from urea hydrolysis responsible for odour productions.
The different N fertilizers did not lead to differences in crop yields, i.e. 18.5 ± 2.9 Mg grain Ha⁻¹ and 17.4 ± 1.2 Mg grain Ha⁻¹ for digestate and urea respectively.
Re-evaluation of NH3 emissions following application of cattle and pig slurry to grassland
Investigation of the effectiveness of abatement techniques.
In 17 field experiments, NH3 emissions were determined with a micrometeorological approach, relating the emission to the measured concentration by means of atmospheric dispersion modelling.
Ammonia (NH3) emissions from land-applied liquid manure (slurry) contribute to nitrogen deposition, acidification, and formation of fine particles in the atmosphere. Optimal management and field application techniques can reduce emission. A reduction in contact area between the slurry and the atmosphere is expected to reduce NH3 emission. The objectives of this study were to develop a method for quantifying the exposed surface area (ESA) of field-applied slurry over time, and determine the degree to which ESA explains differences in NH3 emission. Two experiments were conducted in which untreated, separated, and digested slurry was applied in bands on two different soils with spring oats stubble. Emission data were obtained from online wind tunnel measurements and slurry characteristics such as surface pH, viscosity, and particle size distribution were measured. The new ESA method relies on fluorescent dye added to the slurry prior to field application, followed by imaging. The results show that the ESA measurements can give new insight into the soil-slurry interactions after manure application, and this may help explain why some types of slurry and application techniques lead to successful abatement under some circumstances, but not under others. Furthermore, a pH-, TAN-, temperature-, and ESA-normalised NH3 emission were estimated, helping idetify the effects of infiltration.
The North China Plain (NCP) is one of the most productive and intensive agricultural regions in China. High doses of mineral nitrogen (N) fertiliser, often combined with flood irrigation, are applied, resulting in N surplus, groundwater depletion and environmental pollution. The objectives of this thesis were to use the HERMES model to simulate the N cycle in winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) double crop rotations and show the performance of the HERMES model, of the new ammonia volatilisation sub-module and of the new nitrification inhibition tool in the NCP. Further objectives were to assess the models potential to save N and water on plot and county scale, as well as on short and long-term. Additionally, improved management strategies with the help of a model-based nitrogen fertiliser recommendation (NFR) and adapted irrigation, should be found. Results showed that the HERMES model performed well under growing conditions of the NCP and was able to describe the relevant processes related to soil–plant interactions concerning N and water during a 2.5 year field experiment. No differences in grain yield between the real-time model-based NFR and the other treatments of the experiments on plot scale in Quzhou County could be found. Simulations with increasing amounts of irrigation resulted in significantly higher N leaching, higher N requirements of the NFR and reduced yields. Thus, conventional flood irrigation as currently practised by the farmers bears great uncertainties and exact irrigation amounts should be known for future simulation studies. In the best-practice scenario simulation on plot-scale, N input and N leaching, but also irrigation water could be reduced strongly within 2 years. Thus, the model-based NFR in combination with adapted irrigation had the highest potential to reduce nitrate leaching, compared to farmers practice and mineral N (Nmin)-reduced treatments. Also the calibrated and validated ammonia volatilisation sub-module of the HERMES model worked well under the climatic and soil conditions of northern China. Simple ammonia volatilisation approaches gave also satisfying results compared to process-oriented approaches. During the simulation with Ammonium sulphate Nitrate with nitrification inhibitor (ASNDMPP) ammonia volatilisation was higher than in the simulation without nitrification inhibitor, while the result for nitrate leaching was the opposite. Although nitrification worked well in the model, nitrification-born nitrous oxide emissions should be considered in future. Results of the simulated annual long-term (31 years) N losses in whole Quzhou County in Hebei Province were 296.8 kg N ha−1 under common farmers practice treatment and 101.7 kg N ha−1 under optimised treatment including NFR and automated irrigation (OPTai). Spatial differences in simulated N losses throughout Quzhou County, could only be found due to different N inputs. Simulations of an optimised treatment, could save on average more than 260 kg N ha−1a−1 from fertiliser input and 190 kg N ha−1a−1 from N losses and around 115.7 mm a−1 of water, compared to farmers practice. These long-term simulation results showed lower N and water saving potential, compared to short-term simulations and underline the necessity of long-term simulations to overcome the effect of high initial N stocks in soil. Additionally, the OPTai worked best on clay loam soil except for a high simulated denitrification loss, while the simulations using farmers practice irrigation could not match the actual water needs resulting in yield decline, especially for winter wheat. Thus, a precise adaption of management to actual weather conditions and plant growth needs is necessary for future simulations. However, the optimised treatments did not seem to be able to maintain the soil organic matter pools, even with full crop residue input. Extra organic inputs seem to be required to maintain soil quality in the optimised treatments. HERMES is a relatively simple model, with regard to data input requirements, to simulate the N cycle. It can offer interpretation of management options on plot, on county and regional scale for extension and research staff. Also in combination with other N and water saving methods the model promises to be a useful tool.
Field data on ammonia emission after liquid cattle manure (‘slurry’) application to grassland were statistically analysed to reveal the effect of manure and field characteristics and of weather conditions in eight consecutive periods after manure application. Logistic regression models, modelling the emission expressed as a percentage of the ammonia still present at the start of each period as the response variable, were developed separately for broadcast spreading, narrow band application (trailing shoe) and shallow injection. Wind speed, temperature, soil type, total ammoniacal nitrogen (TAN) content and dry matter content of the manure, application rate and grass height were selected as significant explanatory variables. Their effects differed for each application method and among periods. Temperature and wind speed were generally the most important drivers for emission.
The fitted regression models were used to reveal seasonal trends in NH3 emission employing historical meteorological data for the years 1991–2014. The overall average emission was higher in early and midsummer than in early spring and late summer. This seasonal trend was most pronounced for broadcast spreading followed by narrow band application, and was almost absent for shallow injection. However, due to the large variation in weather conditions, emission on a particular day in early spring can be higher than on a particular day in summer. The analysis further revealed that, in a specific scenario and depending on the application technique, emission could be reduced with 20–30% by restricting manure application to favourable days, i.e. with weather conditions with minimal emission levels.
The Canadian ammonia (NH3) emissions model and a survey of dairy farm practices were used to quantify effects of management on emissions from dairy farms in Ontario Canada. Total NH3 emissions from dairy farming were 21 Gg NH3-N yr-1 for the four ecoregions of the province. Annual emission rates ranged from 12.8 (for calves in ecoregions of Manitoulin-Lake Simcoe-Frontenac) to 50 kg NH3-N animal-1 yr-1 (for lactating cows in ecoregions of St. Lawrence Lowlands) (mean of 27 kg NH3-N animal-1 yr-1). The St. Lawrence Lowlands ecoregion had the highest emission rate because more dairy manure was managed as solid manure in that ecoregion. Total dairy cattle N intake (diet-N) was 81 Gg N yr-1, 23% of which was retained in animal products (e.g., milk, meat, and fetus), 47% was returned to the land, and 30% was emitted as gas (i.e., NH3-N, N2O-N, NO-N, and N2-N) and nitrate-N leaching/runoff. Ammonia volatilization constituted the largest loss of diet-N (26%), as well as manure-N (34%). Reducing the fraction of solid manure by 50% has the potential to mitigate NH3 emissions by 18% in Ontario ecoregions.
Surface-applied swine manure has the potential to generate ammonia (NH 3), nitrous oxide (N 2O) and odour. Field research was conducted in Prince Edward Island to measure the simultaneous emissions of NH 3, N 2O and odour following the surface-application of swine manure. Manure was applied to a grain stubble field consisting of a sandy loam soil low in pH (5.6-5.9). The effect of manure type (liquid and solid), application rate [conventional/typical rate (1x): 30 000-36 000 L ha -1, double (2x): 60 000-72 000 L ha -1 and five times (5x): 180 000 L ha -1] and rainfall (8-200 mm) before and after liquid manure application were examined. There was no relationship between odour emissions and manure type, application rate and rainfall before and after spreading, due to high variability. Liquid manure (dry matter (DM = 45 g kg -1) reduced NH 3 emissions by 32% compared with solid (DM = 350 g kg -1). Increasing application rates enhanced NH 3 emissions; increasing the rate by 2 x and 5 x the typical rate increased losses by 62 and 78%, respectively. Applying manure prior to rainfall reduced NH 3 emissions by 37%, compared with application after a rainfall. Ammonia and odour emissions were similarly correlated to atmospheric conditions with increased emissions at higher air and soil temperature, net radiation, vapour pressure deficit and windspeed. Nitrous oxide emissions were low in magnitude and showed no correlation to climatic conditions, suggesting that management strategies to reduce both odour and NH 3 did not enhance N 2O emissions when applied to a moderately acidic soil with low levels of soil nitrate (<5 mg N kg -1). Our results indicate that for conditions similar to those in this study, there is no trade-off between NH 3 and N 2O production and more attention should be placed on controlling and reducing odour and NH 3 emissions.
Abstract Farm-level ammonia emissions factors in the literature vary by an order of magnitude due to variations in manure management practices and meteorology, and it is essential to capture this variability in emission inventories used for atmospheric modeling. Loss of ammonia to the atmosphere is modeled here through a nitrogen mass balance with losses controlled by mass transfer resistance parameters, which vary with meteorological conditions and are tuned to match literature-reported emissions factors. Variations due to management practices are captured by having tuned parameters that are specific to each set of management practices. The resulting farm emissions models (FEMs) explain between 20% and 70% of the variability in published emissions factors and typically estimate emission factors within a factor of 2. The r2 values are: 0.53 for swine housing (0.67 for shallow-pit houses); 0.48 for swine storage; 0.29 for broiler chickens; 0.70 for layer chickens; and 0.21 for beef feedlots (0.36 for beef feedlots with more farm-specific input data). Mean fractional error was found to be 22–44% for beef feedlots, swine housing, and layer housing; fractional errors were greater for swine lagoons (90%) and broiler housing (69%). Unexplained variability and errors result from model limitations, measurement errors in reported emissions factors, and a lack of information about measurement conditions.
In Denmark, stringent new regulations, placing strict time limits on manure application and setting thresholds for nitrogen utilisation, have been imposed in order to increase the efficiency of uptake of plant nutrients from manure. An important factor in meeting these requirements is the use of operational and cost-effective animal manure handling technologies.An assessment tool covering the whole chain of the manure handling system from the animal houses to the field has been developed. The tool enables a system-oriented evaluation of labour demand, machinery capacity and costs related to the handling of manure. By applying the tool to a pig farm and a dairy farm scenario, the competitiveness of new technologies was compared with traditional manure handling.The concept of a continuous flow of transport and application of slurry using umbilical transportation systems rather than traditional tanker transport may reduce labour requirements, increase capacity, and open up new ways for reducing ammonia emission. In its most efficient configuration, the use of umbilical systems may reduce the labour requirement by about 40% and increase capacity by 80%. However, these systems are costly and will only be profitable for annual applications above 45000t.
This chapter describes the different existing and new promising options for recovering and upgrading manure nutrients and organic matter, and the properties and effectiveness of the biofertilisers produced. Composting of manure solids is described in some detail, since this is one of the dominant technologies currently applied. It reduces volume, mass, odour and pathogens, and enables more distant export for soil fertility maintenance in regions of poor soil quality, but also with potential markets in the non-agricultural sector (landscaping, topsoil, growing media). Manure combustion or gasification for energy production leads to an ash byproduct, which can function as a slow-release potassium or phosphorus fertiliser. However, the ash can also be subjected to chemical extraction or conversion to obtain soluble mineral fertilisers. Pyrolysis of manures for production of biochar-based biofertiliser is an emerging technology, as is precipitation of struvite (MgNH4PO4.6H2O) and high-tech reverse osmosis or ultrafiltration, producing mineral concentrates of high potential fertiliser value.
Some micrometeorological methods for measuring NH(3) loss use passive flux samplers with oxalic acid coated glass tubes. In previous work, we observed that tubes that had been exposed in plots with broiler litter, cleaned with 0.32 mol L(-1) HCl and recoated, had uneven oxalic acid coating, which may lead to NH(3) bypass. One of the objectives of this study was to measure the NH(3)-trapping capacity of previously exposed tubes that were cleaned by either washing and scrubbing with 0.32 mol L(-1) HCl or heating at 560 degrees C for 1 h before being recoated with oxalic acid. There were no detectable differences between cleaning methods in adsorbed NH(3), but tubes cleaned with 0.32 mol L(-1) HCl had uneven oxalic acid coating that led to a 7.3% NH(3) bypass. Tubes cleaned by heating at 560 degrees C for 1 h had even coating and no NH(3) bypass. Presumably, heating the tubes at 560 degrees C oxidized volatile organic compounds bound to the glass, which were acting as nucleating points for oxalic acid. A second objective of this study was to compare a passive flux method with masts on the periphery of a circular plot (PM method) to a method with a central, rotating mast at the center of the plot (CM method). Results from three field studies on tall fescue (Festuca arundinacea Shreb.) pastures showed that the PM method underestimated NH(3) losses by 31 to 37% compared with the CM method. These underestimations were probably caused by NH(3) bypass from tubes exposed to background NH(3). Our results suggest that the CM method may be preferable to the PM method when environmental conditions favor NH(3) bypass.
A model for the transfer of ammonia from arable land to the atmosphere after surface application or incorporation of cattle slurry is presented. The model can be used to study the interactions of the chemical, physical and environmental factors influencing volatilization losses and their combined influence on NH3 volatilization under field conditions. The model employs the following flux equation: R = k (Cs-Ca) where k is a transfer function, Cs is the NH3(g) surface concentration and Ca is the atmospheric NH3(g) background concentration. The rate of volatilization R can be calculated at any moment after application, provided k, Cs and Ca are known at that moment. The model therefore basically consists of modules which yield these variables. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Cattle slurry was surface-applied to bare soil in two experiments in the period September November 1987, while in April-May 1988 two experiments were carried out in which the slur ry was mixed with the upper 6 an of the soil with a cultivator immediately after spreading. The 1987 experiments both lasted 18 days, the 1988 experiments 9 days. A micrometcorologi· cal technique, which did not disturb the dynamics of the air flow, was employed for the NH) volatilization measurements. In addition, volatilization. losses were determined in directly from mineral-N contents of soil/slurry samples collected at intervals after applica· tion.~ Diurnal fluctuations in the NH) flux occurred throughout the experimental period, with maxima around midday and minima at midnight. The magnitude of the daily flux values decreased with time. The amounts of N lost through volatilization from surface·applied cattle slurry were 18 and 33 "0 of the total N, respectively, during the first 9 days, corresponding to 32 and 67 If. of the ammoniacal N applied with the slurry. Volatilization became negligible after day 9.lncor paration of the slurry into the soil considerably decreased the loss of N through volatilization: volatile losses of N after 9 days amounted to 6 and 7 01. of the total N, which corresponds to 11 and 16 .,. of the ammoniacal N applied with the slurry.
Effects of increasing dry matter content in slurry on NH3 loss was measured with a wind tunnel system, whereby parameters affecting the volatilization can be estimated under controlled conditions. The effect of dry matter content on NH3 loss was measured using a slurry adjusted to different contents of dry matter. The slurry was prepared by mixing the fibrous and liquid fractions of a mechanically separated cattle slurry. Slurry was applied to a 5 cm high grass ley (Lolium multiflorum Lam.) and to barley (Hordeum vulgare L.) at a rate of 3 L m-2. The content of dry matter varied from 0.9 to 22% total N from 2.9 to 4.9 g N L-1, TAN (NH3 + NH4+) from 1.6 to 3.0 g N L-1 and pH from 7.0 to 7.9. The results indicated that NH3 volatilization increased with increasing slurry dry matter content. The accumulated 6-d loss ranged from 19 to 100% of applied TAN from slurries having a dry matter content of 0.9 and 15.6%, respectively. The accumulated NH3 loss after 6 h exposure was linearly related to dry matter content. In the periods of 6 to 12 h, 12 to 24 h and 24 h to 6 d the loss was nonlinearly related to dry matter content. If the results were adjusted for effects of pH and temperature, NH3 loss tended to be sigmoidally related to content of dry matter in all four periods. Therefore, changes in slurry dry matter content on NH3 loss seemed to be small if the dry matter content was higher than 12% or lower than 4%.
Ammonia volatilization from stored slurry or surface-applied slurry in the field is strongly affected by pH. Thus a simple, iterative model was developed to predict pH changes in slurry. Concentrations of NH4+/NH3, CO2/HCO3-/CO32- and volatile fatty acids were input data to the model. The model was validated by titrating 17 slurry samples collected from four cattle farms, seven pig farms and three biogas plants. Predictions of pH agreed well for 14 slurries with titration data in the pH interval from 4 to 10. Simulations indicated that microbial degradation of VFA to methane and carbon dioxide resulted in a pH increase if the carbon dioxide produced was lost to the atmosphere. There was little change in pH if the produced carbon dioxide dissolved in the slurry.
The changes in the buffer components and pH in the surface layer of a pig and a cattle slurry were studied in the laboratory of the Department of Soil Science, Lincoln University in 1994. The slurries were spread to a depth of 7 mm in Petri dishes open to the atmosphere. Slurry pH, total inorganic carbon (TIC = CO2 + HCO- + H2CO3), total ammoniacal nitrogen (TAN = NH3 + NH4+) and volatile fatty acids (VFA = C2-C5 acids) were determined at 8–10 intervals after 1–96 h of incubation at 10, 16 and 22 °C. A great increase in pH over the first 8 h was due to the release of CO2. If the initial TIC > TAN, pH then increased steadily but slowly from 8 to 96 h. When the initial TIC < TAN, the pH declined or did not change after 20 h incubation. The initial pH elevation rate increased with temperature and initial concentration of TIC. Calculation indicated that the NH3 partial pressure (PNH3) in equilibrium with the slurry increased and pH decreased at increasing temperature if gases could not exchange between the slurry and the atmosphere. From the open slurry system PNH3 increased with temperature during the first 1–20 h. At 16 and 22 °C the PNH3 declined to low values after 20 h, whereas at 10 °C the PNH3 remained appreciable after 20 h. This explains why high accumulated NH3 losses may occur when slurry is applied to the field at low temperatures.
Three experiments were conducted to examine the influence of slurry application rate, wind speed and applying slurry in narrow bands on ammonia (NH3) volatilization from cattle slurry surface-applied to grassland. The experiments were conducted in the field using a system of small wind tunnels to measure NH3 loss. There was an inverse relationship between slurry application rate and the proportion of NH4+-N volatilized. From slurry applied at 20, 40, 60, 80, 100 and 120 m3 ha-1, the respective proportions of NH4+-N lost by NH3 volatization in 6 days were 60, 56, 49, 40, 44 and 44%. The negative relationship was most pronounced in the first 24 hours after application when 57–77% of the total loss for 6 days occurred. Wind speed had a positive effect on NH3 volatilization, although the effect was small in relation to the total loss; increasing the wind speed from 0.5 to 3.0 m s-1 increased the total 5 day loss by a factor of 0.29. The effect of wind speed was also most pronounced in the first 24 hours when much of the NH3 loss took place. The effect of reducing the surface area of the applied slurry was examined by comparing NH3 volatilization from slurry broadcast across plots with that applied in narrow bands. Although the rate of NH3 volatilization was considerably smaller from the banded application immediately after the slurry was applied, the difference between the treatments progressively narrowed until 2 days after application, after which a higher rate was maintained from the banded slurry. After 5 days the total loss from the banded application was 83% of that from broadcast slurry.
The volatilization of ammonia from applied liquid dairy cattle manure was measured in the field during 6- to 7- day periods in early May of 4 yr. An "open" system involving an aerodynamic diffusion method was employed for these measurements. Ammonia flux followed a diurnal pattern with maxima occurring shortly after midday and minima occurring during the early morning hours. The magnitude of daily flux values tended to decrease with time. However, both temperature and rainfall influenced the magnitude of ammonia flux. Generally, ammonia flux values increased with temperature but were suppressed by rainfall. Over periods of 6 or 7 days following the time of manure application, between 24 and 33% of the ammoniacal N applied in the manure was lost by volatilization. Samples of manure taken immediately following application and 5 days later showed a decrease in ammoniacal N concentration during this period. Although some ammonium moved into the 0- to 2- cm soil layer, immediately following application, most a...
A micrometeorological mass balance technique was used to determine ammonia (NH3) volatilization from pig (Sus scrofa) slurry applied to winter wheat (Triticum aestivum Lam.). The slurry was applied with trail hoses on the soil below the canopy or by a splash plate technique spreading the slurry on both plants and soil. The two application techniques were compared in parallel experiments of 7 d duration on each of nine occasions in the period from April 1993 to June 1995. The loss of NH3 varied from 4 to 26% of the ammonium (NH4/+) in slurry applied with trail hoses and from 11 to 26% when applied with splash plates. Trail hose application reduced NH3 volatilization by up to 80% compared with the losses from splash plate applied slurry. The greatest reduction was observed when slurry was applied to a tall and dense crop, while the trail hose technique did not reduce losses when slurry was applied to a 10 cm high crop with a leaf area index of 0.3. The decreasing NH3 volatilization with increasing crop height was due to a reduced wind speed above the slurry surface, promoted slurry infiltration due to increased drying of the top soil and increasing leaf absorption of volatilized NH3. Wind speed and air temperature above the canopy and the chemical composition of the slurry had little influence on NH3 volatilization from trail hose applied slurry. On the contrary, these factors increased NH3 volatilization from splash plate applied slurry. The NH3 volatilized from trail hose applied slurry was absorbed by the wheat plants in rates from 0 to 0.74 g NH3-N m-2 leaf surface during a period of 7 d after slurry application. Canopy NH3 absorption was responsible for up to 25% of the reduction in NH3 loss when using trail hose application. The wheat plants did not absorb NH3 during stem elongation in the vegetative growth period.
Field experiments were carried out in Brittany (Western France) in 1993 to measure ammonia losses from surface-applied pig and cattle slurry. Experiments were conducted on grass, stubble (wheat and maize) and arable land using a wind tunnel system. Ammonia losses were followed during periods ranging from 20 to 96 h after slurry application. Rates of slurry applied varied from 40 to 200 m3/ha. In two experiments, losses from cattle slurry were respectively 75 and 54% of the ammoniacal nitrogen applied in the slurry. Ammonia emissions from pig slurry applied at a rate of 40 m3/ha, during spring and summer experiments, were higher on grass (45–63% of the total ammoniacal nitrogen applied) than on wheat stubble (37–45%). On average, 75% of the total loss in all experiments occurred within the first 15 h after spreading. Significant correlations were found between ammonia losses (kg N/ha) and mean soil temperature and slurry dry matter content (%) using simple linear regressions and stepwise procedures. The time of application was also found to influence the magnitude of ammonia loss: 83% of the total loss occurred within 6 h when the slurry was applied at midday compared with 42% when it was applied in the evening.
Ammonia (NH3) volatilization may decrease the fertilizer efficiency of surface-applied slurry and may
cause the unwanted deposition of nitrogen (N) in oligotrophic ecosystems. We studied the effect of
soil water content on the infiltration of slurry liquid and how infiltration affected NH3 volatilization.
NH3 volatilization was measured with dynamic chambers through which air was drawn continuously.
Slurry spiked with bromide (Br−) to trace slurry infiltration was applied to a loamy sand in steel
cylinders (diameter 6·7 cm and height 12 cm) adjusted to water contents of 0·01, 0·08, 0·12 and
0·19 g H2O per g soil (g g−1). At different time intervals after slurry application the soil columns were
cut into slices and Br−, ammonium (NH4+) and nitrate
(NO3−) concentrations were determined. At
soil water contents >0·12 g g−1 nitrate content increased
significantly from 24 to 72 h, and at 96 h NO3− content was
equivalent to 75–130% of the NH4+ present at 0·5 h after slurry application.
Nitrification may have contributed to a low NH3 volatilization from 24 to 96 h by reducing NH4+
concentration and contributing to acidity, and most of the NH3 volatilization occurred, therefore,
during the first 24 h after application. Low soil water content enhanced the infiltration of slurry liquid
and hence the mass transport of NH4+ into the soil. Transport of
NH4+ by diffusion, on the other
hand, was highest at the highest water content. Transport of NH4+
from the slurry at the soil surface
down into the soil at 0·01 g g−1
reduced NH3 volatilization to c. 70% of the volatilization from slurry
applied to soils at higher water contents. Diffusion of NH4+
into the soil did not significantly decrease
NH3 volatilization.
In 1989 three experiments with up to three different treatments each were carried out in North Germany to determine the ammonia flux densities after the application of liquid slurry using the micrometeorological mass balance method.
In Expts 1 and 2, pig slurry was applied with a conventional surface spreader to wheat stubble. The results demonstrated the influence of meteorological conditions and that of incorporation on the extent of ammonia volatilization. In comparison to warm and windy conditions, NH 3 losses decreased from 56% of the NH 4 -N applied to wheat stubble to 42% during a cool and rainy period. When slurry was incorporated immediately into the soil, ammonia losses were significantly reduced to 20 and 10%, respectively, of the applied NH 4 -N. The highest losses (67% NH 4 -N) were found when slurry was applied during warm weather on wheat stubble covered with chopped straw. Soil cultivation of the wheat stubble before the application of slurry diminished the ammonia emission from 42 to 28% of the NH 4 -N.
In Expt 3, cattle slurry was applied to rape. It was found that compared with a conventional surface spreader the ammonia volatilization was reduced from 68 to 58% of the NH 4 -N when an alternative distribution system consisting of drag hoses was used for the application.
A new method of calculation of vapor-liquid equilibria for ammonia/hydrogen sulfide/water and ammonia/carbon dioxide/water at 0/sup 0/-100/sup 0/C at the concentrations encountered in refinery sour water strippers and for ammonia/sulfur dioxide/water as found in gas cleaning systems was developed. The model was based on the Edwards et al. thermodynamic approach.
Field experiments under various conditions were carried out in Hohenheim and the Allgäu to measure the effects of liquid manure properties and meteorological factors on ammonia losses. The micrometeorological method (IHF) and the wind tunnel method were used. Depending on the prevailing conditions the ammonia losses varied between 14 and 99% of the applied ammonium nitrogen. The relationship between the ammonia loss and the logarithm of the dry matter content of liquid manure was highly significant. The dry matter content also influenced the time course of the ammonia loss. Solar radiation was the other major factor affecting ammonia loss. Compared to dry matter content and-solar radiation, effects of other factors such as ammonium content and pH of liquid manure, air temperature, relative humidity and wind speed were small in the given range tested. Based on the relationships between the various parameters a simple model for estimation of ammonia loss was developed.
Critical loads for N deposition are derived from an ecosystem's anion and cation balance assuming that the processes determining ecosystem stability are soil acidification and nitrate leaching. Depending on the deposition of S, the parent soil material, and the site quality critical N deposition rates will range between 20 to 200 mmol m–2 yr–1 (3 to 14 kg ha–1 yr–1) on silicate soils and reach 20 to 390 mmol m–2 yr–1 (3 to 48 kg ha–1) on calcareous soils.
A new type of passive sampler for the determination of NH3 emission from land surfaces and manure storages was tested in a micrometereological mass balance method. The sampler consists of 2 glass tubes, each with a length of 10 cm and an internal diameter of 0.7 cm. The two glass tubes are connected in series, with one end fitted with a thin stainless steel disc having a 1 mm hole in the center. The inner surface of each glass tube is coated with oxalic acid. The results show that the passive flux sampler can be used to give accurate determinations of NH3 emission. The passive flux sampler makes gas washing bottles, pumps, flow meters, anemometers, and electricity unnecessary and ammonia loss can be determined easily and cheaply without the requirement of a large labor force.
Measurements of dry, deposition velocities (V
d
) of O3 (using the eddy correlation technique) made over a cotton field and senescent grass near Fresno California during July and August 1991 were used to test some dry deposition velocity models. Over the cotton field, the observed maximum daytimeV
d
was about 0.8 cm s–1 and the average nighttime value was about 0.2 cm s–1. Over the grass, daytime values averaged about 0.2 cm s–1 and nighttime values about 0.05 cm s–1. Application of a site-specific model known as ADOM (Acid Deposition and Oxidant Model) over the cotton field generally overestimated the observations except for a few hours in the afternoon when the observations were underestimated The overestimation was attributed to inadequacies in the surface resistance formulation and the underestimation to uncertainties in the aerodynamic formulation. Unlike previous studies which focused on the role of surface resistance, we perform additional tests using a large variety of aerodynamic resistance formulae, in addition to those in ADOM, to determine their influence on the modelledV
d
of O3 over, cotton. Over grass, ADOM considerably overestimated the observations but showed improvement when other surface resistance formulations were applied.
The loss of ammonia by volatilization after slurry application may lead to large losses of soil-plant nitrogen. It is also a major source of atmospheric ammonia. These fluxes must therefore be accurately measured. However, volatilization depends on many features of the soil, climate and slurry, so that it is difficult to predict, or even to interpret and compare data from different experiments. We have developed a mechanistic model that simulates the influence of the various factors on volatilization, accounting for the transfers and equilibria in the topsoil and between the soil and the atmosphere. The model uses readily available input data, including soil, meteorological and slurry data. It includes energy balance and advection submodels, which make it suitable for field scale applications using simple meteorological data. Sensitivity analysis showed that soil pH has a large influence on volatilization. The model is also sensitive to soil adsorption capacity and some hydraulic characteristics (saturation water conductivity, water content at field capacity). It has been calibrated under real field conditions using experimental data for ammonia fluxes measured over two weeks after slurry application, with a micrometeorological method giving data at 15-min intervals. The soil, climate and slurry factors were also measured. The model provides a fair picture of the ammonia fluxes throughout the volatilization, including the total ammonia volatilized, the decrease in daily loss and their short-term (< 1 h) variations due to the influence of meteorological conditions on soil surface temperature and atmospheric diffusion. Lastly the model has been used to simulate the influence of various meteorological conditions and agricultural techniques on ammonia volatilization. This model will make it easier to interpret data from different experiments and will help to improve the emission submodel of atmospheric ammonia deposition models.
Vegetation is treated as a complex surface roughness to which the transfer of mass or heat encounters greater aerodynamic resistance, γP, than the transfer of momentum, γD. The excess resistance (γP – γD) is equated to B/u*, where B−1 is the non-dimensional bulk parameter introduced by Owen and Thomson (1963) and used by Chamberlain (1966, 1968). A general expression is obtained for B−1 in terms of the exchange characteristics of the individual elements of a vegetative canopy: this expression does not contain the surface roughness parameter Z0.
Using exchange coefficients of individual bean leaves (Thom 1968) and the bulk momentum absorption properties of a particular bean crop (Thom 1971) the relation B−1 = (constant) u*1/3 is derived. With u* in cm s−1, the constant is 1.35 for heat exchange and transpiration, 2.18 for CO2 exchange, and 1.13 for evaporation from the crop when wet. It is suggested, partly on the basis of the lack of dependence of B−1 on z0, that the same set of equations may provide a first approximation to B−1 for many types of vegetation.
Demonstrated are (i) that Monteith's (1963) method of extrapolating to zero wind speed to determine representative surface values of vapour pressure and of temperature (es and Ts) is much more rigorous if extrapolation is made to u = −B−1u* rather than to u = 0; and (ii) that the surface resistance γS, proportional to (ew(Ts) − es) (Monteith 1965) exceeds the bulk physiological, or stomatal, resistance γST of vegetation by an amount {1 − (Δ/γ).β}.B−1/u*, significant only when the Bowen ratio β is less than about 3/4(γ/Δ). (γ = 0.66 mb °C−1; Δ = dew/dT.) In particular, for B−1 = 4 and β = 0: (i) γST = 1/3 to 1/2 of γS; and (ii) use of γS with γD in the Penman equation (instead of γS, with which γD is compatible) overestimates λE by about 15 per cent.
A method is described for the minimization of a function of n variables, which depends on the comparison of function values at the (n + 1) vertices of a general simplex, followed by the replacement of the vertex with the highest value by another point. The
simplex adapts itself to the local landscape, and contracts on to the final minimum. The method is shown to be effective and
computationally compact. A procedure is given for the estimation of the Hessian matrix in the neighbourhood of the minimum,
needed in statistical estimation problems.
Ammonia volatilization from liquid dairy cattle manure in the "eld Representation of NH }H sign and Development 17 Ammonia emission from slurry applied to wheat stubble and rape in North Germany Estimation of ammonia losses after application of liquid cattle manure on grassland
- E G Beauchamp
- G E Kidd
- G Thurtell
- D Beutier
- H Renon
- H.-G Bless
- R Beinhauer
- B Sattelmacher
Beauchamp, E.G., Kidd, G.E., Thurtell, G., 1982. Ammonia volatilization from liquid dairy cattle manure in the "eld. Canadian Journal of Soil Science 62, 11}19. Beutier, D., Renon, H., 1978. Representation of NH }H sign and Development 17, 220}230. Bless, H.-G., Beinhauer, R., Sattelmacher, B., 1991. Ammonia emission from slurry applied to wheat stubble and rape in North Germany. Journal of Agricultural Science, Cambridge 117, 225}231. Braschkat, J., Mannheim, T., Marschner, H., 1997. Estimation of ammonia losses after application of liquid cattle manure on grassland. Zeitschaft fuK r P#anzenernaK hrung und Boden-kunde 160, 117}123. ECETOC, 1994. Ammonia Emissions to Air in Western Europe. Technical Report No. 62. European Centre for Ecotoxicol-ogy and Toxicology of Chemicals, Brussels, Belgium.Pp196.
Ammonia volatilization from cattle slurry following surface applica-tion to grassland. II. In#uence of application rate, wind speed and applying slurry in narrow bands Ammonia volatilization from arable land after application of cattle slurry. 1. Field estimates
- R B Thompson
- B P Pain
- Y J J Rees
- H G Van Fassen
- M Y Leclerc
- R Vriesema
- W J J Chardon
- A C M Beljaars
- W J Chardon
Thompson, R.B., Pain, B.P., Rees, Y.J., 1990. Ammonia volatilization from cattle slurry following surface applica-tion to grassland. II. In#uence of application rate, wind speed and applying slurry in narrow bands. Plant Soil 125, 119}128. van der Molen, J., van Fassen, H.G., Leclerc, M.Y., Vriesema, R., Chardon, W.J., 1990a. Ammonia volatilization from arable land after application of cattle slurry. 1. Field estimates. Netherlands Journal of Agricultural Science. 38, 145}158. van der Molen, J., Beljaars, A.C.M., Chardon, W.J., Jury, W.A., van Fassen, G.G., 1990b. Ammonia volatilization from ar-able land after application of cattle slurry. 2. Derivation of a transfer model. Netherlands Journal of Agricultural Science 38, 239}254.
Scienti"c basis for an integrated nitrogen approach A mechanistic model for estima-ting ammonia volatilization from slurry applied to bare soil
- J W Erisman
- J Mosquera
- A Hensen
- S Cellier
Erisman, J.W., Mosquera, J., Hensen., A, 1999. Scienti"c basis for an integrated nitrogen approach. In: Nielsen, H.E., et al. (Eds.), 10th Nitrogen Workshop 23}26 August. The Royal Veterinary and Agricultural University, Copenhagen, Den-mark, pp. II.7. GeH nermont, S., Cellier, P., 1997. A mechanistic model for estima-ting ammonia volatilization from slurry applied to bare soil. Agriculture and Forest and Meteorology 88, 145}167.
Calibration of passive flux samplers measuring horizontal atmospheric NH3 fluxes
- Hansen
Hansen, B., 1995. Calibration of passive #ux samplers measuring horizontal atmospheric NH #uxes. Aarhus Geoscience 3, 93}96.
Ammonia emissios after land spreading of animal slurries Ammonia and Odour Emis-sions from Livestock Production Normtal for hus-dyrg+dning } En revurdering af danske normtal for husdyrg+dningens indhold af kvvlstof, fosfor og kalium
- J V Klarenbeek
- M A Bruins
- C D Nielsen
- J H Voor-Burg
- L Hermiteh
Klarenbeek, J.V., Bruins, M.A., 1991. Ammonia emissios after land spreading of animal slurries. In: Nielsen, C.D., Voor-burg, J.H., L'HermiteH, P. (Eds.), Ammonia and Odour Emis-sions from Livestock Production. Elsevier Applied Science, London, pp. 107}115. Kristensen H.D., Kristensen, V.F., 1997. Normtal for hus-dyrg+dning } En revurdering af danske normtal for husdyrg+dningens indhold af kvvlstof, fosfor og kalium. Beretning nr. 736, pp 75}79. Ministeriet for F+devarer, Landbrug og Fiskeri, Danmarks Jordbrugsforskning, Tjele, Denmark.
Scientific basis for an integrated nitrogen approach
- J W Erisman
- J Mosquera
- A Hensen
Karakterisering af jordarealer omkring Forskningscenter Foulum (Characterization of the area surrounding Research Centre Foulum). Tidsskrift for Planteavls Specialserie, Beretning nr. S 2229-1992
- P Schjønning
Representation of NH3–H2S–H2O, NH3–CO2–H2O, and NH3–SO2–H2O vapor–liquid equilibria
- Beutier
Normtal for husdyrgødning - En revurdering af danske normtal for husdyrgødningens indhold af kvælstof, fosfor og kalium. Beretning nr
- H D Kristensen
- V F Kristensen
Ammonia volatilization from pig slurry applied with trail hoses or broadspread to winter wheat
- Sommer