EVALUATION OF AMMONIA RELEASES IN FREE RANGE BROILER PRODUCTION IN THE PAYS DE LA LOIRE

LARAVOIRE, A.¹, PONCHANT, P.², ROBIN, P.³,HASSOUNA, M.³, DENNERY, G.¹, PIGACHE, E.¹

1 Chambre régionale d’agriculture des pays de la Loire, France

2 ITAVI, France

3 INRA, France

ABSTRACT: The negative impact of ammonia on environment and human health has led to a strengthening of regulations with the Göteborg protocol. This one imposes a reduction of nitrogen by 4% between 2005 and 2020. To meet these environmental commitments the technical center for studies on atmospheric pollution conduct an inventory of emissions and pollutants annually. However, uncertainties remain concerning the calculation of ammonia emissions for free range productions. The study on the

"Evaluation of Ammonia releases in free range broiler production" aims to acquire, a value of ammonia emission taking into account the particularities of free range broiler production. A simplified protocol to measure the ammonia for free range broiler was set.

The average of ammonia emission for free range broiler is 23.70 ± 11.53 g NH3/animal/rearing period. This result is similar to the CORPEN 2006 and ITAVI 2013:

27.90 ± 14.00 g/animal/rearing period.

Keywords: NH3, Poultry, Measuring method, Inventory.

INTRODUCTION: The Göteborg protocol sets a commitment to reduce nitrogen emissions by 4% by 2020 compared to 2005, and targets of 13% reduction by 2020 are expected under the NEC Directive (2001/81/CE). In order to meet these international commitments made by France, the interprofessional technical center for studies on air pollution (CITEPA) is responsible for carrying out annually an inventory of emissions and polluting substances. It is based on calculations methodologies recognized by international experts (EMEP/CORINAIR, IPCC, etc.) and technical data specific to national agricultural practices (standard value ITAVI 2013) to obtain representative calculations. The CORPEN 2006 (Poultry Group) indicates that an ammonia emission factor of 30% (±15%) is representative of the different poultry production. Applied to the standard value of specific nitrogen excreted by production (ITAVI, 2013), it allows the calculation of the corresponding emission value of ammonia (NH

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two stages: development of a protocol of measures adapted to outdoor production (with exit to a range) and easy to use (practically and equipment cost). This protocol adapted to the production of outdoor broiler, made it possible to carry out measurements, and thus to obtain an emission value of ammonia specific to this production.

1. MATERIAL AND METHODS

1.1 Development of a simplified protocol to measure the concentration of ammonia into the barn: The protocol used for measurements in conventional farms is based on the realization of a mass balance and on the method of concentration gradients: indoor and outdoor air samplings at different periods of the rearing period are carried out and the air is then analyzed by infrared spectrometry (analyzer INNOVA®) (Ponchant et al., 2009). In our study, by economical choice and ease of the use, the portable Kimo ToxiRAE2®

ammonia detector was chosen. It was necessary to ensure that the ammonia concentrations measured with the detector are similar to the one with the gas analyzer used in the simplified method. This phase was carried out in a pilot farm with two identical buildings. In order to obtain representative measurements of the whole barn (width and length, with and without exit traps, entrance and bottom), the portable ammonia detector was used to make 8 measurements inside and 3 measurements outside the barn (one per sprocket and one at the level of a long side), i.e. one measure per accessible side. The measurements were made about 1 meter above the ground. At the same time, sampling were carried out according to the reference method (Ponchant et al., 2009). Therefore, 2 round trips were carried out in the barn, using SKC FlexFoil® PLUS sample bag and an aquarium pump to collect air in the bag. A round trip outside the barn, along the long side was also carried out. The air samples were then analyzed by the gas analyzer INNOVA®

Airtech Instrument 1412 Photoacoustic Field Gas Monitor giving an ammonia concentration (converted in ppm) every minute. The average concentration of ammonia obtained by the analyzer in each barn (10 analyzes/barn) was compared with the average concentration obtained with the ToxiRAE2® detector in the building (8 measurement points/barn).

In the case of free range farms, it was necessary to determine the number of follow ups required during the rearing period. To obtain the kinetics of evolution during this period, daily measurements were carried out in the 2 pilot barns, with the portable ammonia detector. The measurements were taken 1 time per day. In order to obtain an estimate of the average ammonia concentration in the barn, the 8 measurements were carried out, distributed throughout the building. These series of measurements made possible to identify the evolution of the concentrations of ammonia in the building and thus to identify the number of follow-ups needed during the rearing period to obtain a representative ammonia concentration.

1.2. Calculation of the emission of ammonia in broiler production in the Pays de la Loire:

The study took place in 2015 and 2016 in Pays de la Loire. A total of 22 broiler barn « Label rouge » were monitored during the summer period and 13 of them during the winter period (it was not possible to carry out a second follow up of the 9 others). 4 productions organizations were represented. The farms monitored were characterized by buildings of 400 m² in static ventilation (transversal or high extraction) with clay floors.

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To calculate an emission of ammonia in g/animal/rearing period it was needful to determine the ventilation rate in the barn. For the calculation, it is necessary to collect:

the broiler weight, temperature and hygrometry inside and outside the barn. These parameters make possible to calculate the energy inputs and losses in the form of heat in the barn according to the following formula (Hassouna et al, 2005): Heat inputs (in W) = Heat losses (in W): AI + HI + LF + SI = WL + VL + EV with : AI : inputs from animals ; HI : Inputs by heating ; LF : Fermentation of litter; SI : solar inputs (negligible) ; WL : Losses by the walls ; VL : Ventilation losses ; EV : Evaporation losses of water (negligible). VL corresponds to the enthalpy in W/animal lost by ventilation. The ventilation rate (m³/h/animal) corresponds to the ratio VL/energy difference (J/kg dry air) calculated at the different temperatures and hygrometries between the indoor and outdoor air, multiplied by its density, per hour. Emissions of ammonia can then be calculated using the following formula: Emission = Ammonia concentration x Ventilation rate.

In our study, the weight of the animals was obtained from the animal weighing by the breeder. The temperature and humidity measurements were carried out inside and outside the barn using a KIMO AMI 301® probe, according to the same measurements of ammonia. In order to obtain the cumulative emission over the total duration of the rearing period, it was necessary to estimate the emission for the days between the visits. For this purpose, a linear estimate was made before the first measurement day, and from the first visit to the end, a polynomial estimate allowed us to approximate the daily emission. Thus, the total ammonia emission in g/animal/rearing period corresponds to the sum of the emissions estimated daily. The ammonia emission value calculated in free range broiler was then compared to the one calculated from the excreted nitrogen emission factor of 30

% (±15%) (CORPEN, 2006) and the average level of nitrogen excreted in the barn (standard value) by free range broiler (ITAVI, 2013).

1.3. Season and ammonia: To evaluate the season effect on ammonia emission, a Wilcoxon comparison test was carried out at α=5% risk on summer and winter data.

2. RESULTS AND DISCUSSION

2.1. Development of a simplified protocol: There was no significant difference in ammonia concentration measurements using the portable ammonia detector (1,61 mg NH3/m³) or the gas analyzer (1,63mg NH3/m³) (P=0,98). The portable ammonia detector can replace the gas analyzer in the simplified protocol.

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To obtain a concentration value of ammonia corresponding to daily measurements, one measure must be taken before the opening of the traps, around 35 days of age, and another after the opening of the traps towards 50 days. To take into account the concentration of ammonia at start up, a measurement must be carried out around 20 days since the emission of ammonia from litter begins around 15 days (CORPEN, 2006). A last measurement will be carried out around 65 days to estimate the concentration of ammonia at the end of the rearing period. This represents a total of 4 measures (20-35-50 and 65 days). Results were similar between the two measurement protocol (p=0.76) thus, it is possible to obtain a concentration value of ammonia close to that obtained with daily measurements.

2.2. Ammonia emissions inside the barn from free range broiler: The average concentration of ammonia (ppm) into the barn of free range broiler is 5,80 ± 4,47 ppm (min : 1,60 ; max : 21,20) with an uncertainty of calculation of 1,16 ppm due to the 20%

uncertainty of the portable ammonia detector. The average ammonia emission was 23,70

± 11,53 g of NH3/animal/rearing period (min : 9 ; max : 52) with a calculation uncertainty of 7,11 g/animal/rearing period corresponding to an error of 30 % due to the possible approximation of the heat generated by the animals in the barn, equivalent to 10,36 ± 3,11 g of NH₃/kg body weight/rearing period. Considering the variability encountered on livestock emissions, this result is close to the value obtained from the information from the CORPEN 2006 and ITAVI 2013 : 27,90 g of NH3/animal/rearing period with an uncertainty of 14 g/animal/rearing period because the excreted ammonia is within a range of 15 and 45 % of the outdoor excreted nitrogen that is 88 g/animal.

2.2. Season effect: In summer period, the ammonia emission value is 27,30 ± 12,53 g/animal/rearing period (min : 12,90 ; max : 51,90) with a calculation uncertainty of 8,19 g/animal/rearing period. The winter ammonia emission is 20,00 ± 10,26 g/animal/rearing period (min : 9,30 ; max : 50,10) with a calculation uncertainty of 6 g/animal/rearing period. Summer and winter emissions are significantly different (p <0,01). This can be explained by a greater activity of the animals during the summer period.

3. CONCLUSION: This study resulted in a simplified measurement protocol for ammonia concentration in free range broiler barn using an easy equipment (portable ammonia detector) and responding to specificity of free rang production. This protocol can be easily used by everyone to mesure ammonia concentration and then calculate ammonia emissions. An average ammonia emission value in the barn for free range broiler of 23,70

± 11,53 g of NH3/animal/rearing period calculated from measurements in « Pays de la Loire ». These results are consistent with the calculated data from the CORPEN, 2006 and ITAVI, 2013.

Acknowledgements. This project was financed by the « Pays de la Loire » region and the French Ministry of Agriculture. We sincerely thank all participants in this study.

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REFERENCES:

CITEPA., 2015.Rapport national d’inventaire. Inventaire des émissions de polluants atmosphériques et gaz à effet de serre en France. Séries sectorielles et analyses étendues.

CORPEN., 2006.Estimation des rejets d’azote – phosphore – potassium – calcium – cuivre et zinc par les élevages avicoles.

ITAVI., 2013.Estimation des rejets d’azote – phosphore – potassium – calcium – cuivre et zinc par les élevages avicoles.

Ponchant P., Hassouna M., Aubert C., Robin P., Amand G., 2009.Application et validation d’une méthode de mesures simplifiées des gaz à effet de serre en bâtiment avicole.

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