TY - CHAP

T1 - Ammonia volatilization after application of biogas slurries in a coastal marsh region of Northern Germany

AU - Quakernack, R.

AU - Techow, A.

AU - Hermann, A.

AU - Taube, F.

AU - Kage, Henning

AU - Pacholski, Andreas Siegfried

N1 - Conference code: 23

PY - 2010

Y1 - 2010

N2 - Biogas production has increased rapidly in Germany, resulting in large amounts of biogasslurries. Physico-chemical properties of biogas slurries differ from those of conventionalanimal slurries. Due to this fact a field study has been established to determine ammonialosses by volatilization after supply of biogas slurries in grassland. Perennial ryegrass (Loliumperenne) was tested as an alternative to conventional biogas crops (silage maize, silagecereals) in the marsh region of Schleswig-Holstein in Northern Germany. Yield wasdetermined under different N-fertilisation-levels of mineral fertiliser (CAN) and biogas slurryapplied by trail hoses. Ammonia losses are mainly influenced by climate conditions and wereinvestigated by a micrometeorological approach, backwards Lagrangian stochastic dispersionmethod. Because of strong wind in the coastal region the major fraction of the ammoniaemissions were observed within the first 10 hours after application. The NH3-losses byvolatilization were higher than in other regions of Schleswig-Holstein and substantiallydecreased yield of perennial ryegrass.Keywords: Ammonia volatilization, Biogas slurry, Fertiliser value, Energy crop rotationIntroductionBiogas plays an important role in the German bio-energy production, with energy crops(silage maize, silage cereals) particularly grown as fermentation substrates. It is not only incoastal regions of Germany that grass can also serve as an alternative to the predominantbiogas-crop, maize. However, the overall environmental benefit from growing of energycrops may be reduced by NH3-emissions after application of biogas slurries, unavoidable inthese production systems. NH3-emissions are among the main sources of acidifying andeutriphying atmospheric compounds and are considered as indirect greenhouse gas emissions.Furthermore the N-fertilisation value of organic fertilisers can strongly be reduced by NH3-volatilization (Sommer and Hutchings, 2001). Marshlands are typical regions for grasscultivation and characterised by very particular growing conditions because of shallowgroundwater levels, heavy, silt-clayey soils (Fluvimollic Gleysol) and strong wind speedswhich can also strongly influence NH3loss processes. There exists only very limitedinformation on the potential NH3-losses under such conditions.Materials and methodsAmmonia (NH3) losses after application of biogas slurries on grassland by trail hoses weredetermined on larger field plots (1 plot per fertilisation) by using the micrometeorologicalbackwards Lagrangian stochastic dispersion technique (bLS, Sommeret al., 2005) in themarsh of the federal state of Schleswig-Holstein, Northern Germany. The plot size of eachfertilisation date depended on the working width of the trail hoses, which varied between thedifferent dates of fertilisation (plot sizes at investigated fertilisations: 07.04.09: 48 m x 48 m;Grassland Science in Europe, Vol. 1526828.05.09: 54 m x 54 m; 01.07.09: 36 m x 36 m). Yield of perennial ryegrass was investigatedin a multi-plot field trial including a bi-annual energy crop rotation consisting of maize (Zeamays), wheat (Triticum aestivum), Italian ryegrass (Lolium multiflorum) and the monoculturesof maize and perennial ryegrass. The latter was cut four times. Nitrogen fertilisers tested inthis study included co-fermented biogas slurry (BGS) and CAN as mineral fertilizer. Besidesthe control treatments, N was applied in two levels (360 kg ha-1subdivided in 120/120/70/50and 480 kg ha-1subdivided in 165/145/100/70 kg ha-1). Plot size was 12 m x 12 m with fourreplicates for each treatment. Ammonia loss measurements after biogas slurry applicationwere carried out on the same date and with the same N-supply as for the moderate N-leveltreatment (360 kg ha-1N). Ammonia losses from CAN were considered as negligible. Yield ofperennial ryegrass [t ha-1] was statistically analysed by two-way ANOVA including N-formand N-levels as treatment factors.Results and discussionNitrogen losses by NH3-volatilization differed between dates of fertiliser application. Figure 1shows the cumulative and the relative ammonia losses after biogas slurry application ongrassland determined in 3 experimental campaigns.Figure 1 Cumulative and relative N-loss by NH3-volatilization after application of biogasslurry in different N levels, perennial ryegrass (Lolium perenne), marsh region of Schleswig-Holstein, micrometeorological bLS-technique, 3 dates during spring and summer 2009.After N-application relative losses of about 20% of NH4-N applied could be observed on theapplication dates 7 April and 1 July, whereas on 28 May the NH3-losses were higher than30% of supplied NH4-N. The higher relative losses were probably due to strong wind on 28May, which is one of the main driving factors for NH3-volatilization. Average wind speed at aheight of 2 metres for the first few hours after application was 7.4 m s-1, much higher than on7 April (3.6 m s-1) and on 1 July (2.4 m s-1). NH3-volatilization losses after slurry applicationGrassland in a ChangingWorld269with trail hoses in the marsh were about two fold higher than in other landscapes ofSchleswig-Holstein(Pacholskiet al., 2009).The yield of ryegrass was significantly lower for every cut in the biogas slurry treatment ascompared to mineral fertilisation. No interaction between N fertiliser and N level wasobserved (Fig. 2).Figure 2 Dry matter yield [t ha-1] of perennial ryegrass, cut 4 times a year, at a moderate (360kg ha-1N) and a high level (480 kg ha-1) of N fertilization with biogas slurry (BGS) andmineral fertilizer (CAN) in the marsh region of Schleswig-Holstein. Values with differentletters are statistically different atP<0.05 (Tukey-test, n=4).As a result the total DM yield decreased from 14.5 t ha-1(CAN) to 8.5 t ha-1(BGS) by about42% under the lower N level, and from 17.3 t ha-1(CAN) to 10.4 t ha-1(BGS) about 40%under the high N level (Fig. 2). The data suggest that N-losses by NH3-volatilization were themain factor for high differences in yield levels between the two N-fertilisers. In addition,lower yields under biogas slurry fertilisation could also be due to ammonium adsorption andfixation in the soil characterized by high clay contents, N2O-losses by microorganisms or N-leaching. Besides environmental impact, like acidification and eutrophication, NH3-volatilization can thus also strongly influence the N-fertilisation value of biogas slurry.Nevertheless, a DM yield of 14.5 t ha-1for grass with mineral fertilisation was competitive tothe yield of dominant biogas crop maize at this site (average of 15 t ha-1).ConclusionFertilisation of biogas slurries with trail hoses can lead to high N-losses by NH3-volatilization.Losses were even higher than 30% of NH4-N applied, in situations with strong winds. Thoselosses substantially contributed to strongly decreased yields of perennial ryegrass and highenvironmental impact. In the study region, grasses cut 4 times a year can be considered as arealistic alternative to maize as substrate for biogas production due to similar dry matter yieldlevels.ReferencesPacholski A., Gericke D. and Kage H. (2009) Measurement and modelling of NH3 emissions from field-appliedbiogas residues in North German energy crop rotations. In: Grignani C., Acutis M., Zavattaro L., Bechini L.Bertora C., Marino Gallina P. and Sacco D. (eds.)Proceedings of the 16th Nitrogen Workshop - Connectingdifferent scales of nitrogen use in agriculture. 28th June – 1st July 2009, Turin, Facolta di Agraria, Turin, Italy,189-190.Sommer S.G. and Hutchings N.J. (2001) Ammonia emission from field manure and its reduction – invited paper,European Journal of Agronomy15, 1-15.Sommer S.G., McGinn S.M. and Flesch T.K. (2005) Simple use of the backwards Langrangian stochasticdispersion technique for measuring ammonia emission from small field-plots.European Journal of Agronomy23, 1-7.

AB - Biogas production has increased rapidly in Germany, resulting in large amounts of biogasslurries. Physico-chemical properties of biogas slurries differ from those of conventionalanimal slurries. Due to this fact a field study has been established to determine ammonialosses by volatilization after supply of biogas slurries in grassland. Perennial ryegrass (Loliumperenne) was tested as an alternative to conventional biogas crops (silage maize, silagecereals) in the marsh region of Schleswig-Holstein in Northern Germany. Yield wasdetermined under different N-fertilisation-levels of mineral fertiliser (CAN) and biogas slurryapplied by trail hoses. Ammonia losses are mainly influenced by climate conditions and wereinvestigated by a micrometeorological approach, backwards Lagrangian stochastic dispersionmethod. Because of strong wind in the coastal region the major fraction of the ammoniaemissions were observed within the first 10 hours after application. The NH3-losses byvolatilization were higher than in other regions of Schleswig-Holstein and substantiallydecreased yield of perennial ryegrass.Keywords: Ammonia volatilization, Biogas slurry, Fertiliser value, Energy crop rotationIntroductionBiogas plays an important role in the German bio-energy production, with energy crops(silage maize, silage cereals) particularly grown as fermentation substrates. It is not only incoastal regions of Germany that grass can also serve as an alternative to the predominantbiogas-crop, maize. However, the overall environmental benefit from growing of energycrops may be reduced by NH3-emissions after application of biogas slurries, unavoidable inthese production systems. NH3-emissions are among the main sources of acidifying andeutriphying atmospheric compounds and are considered as indirect greenhouse gas emissions.Furthermore the N-fertilisation value of organic fertilisers can strongly be reduced by NH3-volatilization (Sommer and Hutchings, 2001). Marshlands are typical regions for grasscultivation and characterised by very particular growing conditions because of shallowgroundwater levels, heavy, silt-clayey soils (Fluvimollic Gleysol) and strong wind speedswhich can also strongly influence NH3loss processes. There exists only very limitedinformation on the potential NH3-losses under such conditions.Materials and methodsAmmonia (NH3) losses after application of biogas slurries on grassland by trail hoses weredetermined on larger field plots (1 plot per fertilisation) by using the micrometeorologicalbackwards Lagrangian stochastic dispersion technique (bLS, Sommeret al., 2005) in themarsh of the federal state of Schleswig-Holstein, Northern Germany. The plot size of eachfertilisation date depended on the working width of the trail hoses, which varied between thedifferent dates of fertilisation (plot sizes at investigated fertilisations: 07.04.09: 48 m x 48 m;Grassland Science in Europe, Vol. 1526828.05.09: 54 m x 54 m; 01.07.09: 36 m x 36 m). Yield of perennial ryegrass was investigatedin a multi-plot field trial including a bi-annual energy crop rotation consisting of maize (Zeamays), wheat (Triticum aestivum), Italian ryegrass (Lolium multiflorum) and the monoculturesof maize and perennial ryegrass. The latter was cut four times. Nitrogen fertilisers tested inthis study included co-fermented biogas slurry (BGS) and CAN as mineral fertilizer. Besidesthe control treatments, N was applied in two levels (360 kg ha-1subdivided in 120/120/70/50and 480 kg ha-1subdivided in 165/145/100/70 kg ha-1). Plot size was 12 m x 12 m with fourreplicates for each treatment. Ammonia loss measurements after biogas slurry applicationwere carried out on the same date and with the same N-supply as for the moderate N-leveltreatment (360 kg ha-1N). Ammonia losses from CAN were considered as negligible. Yield ofperennial ryegrass [t ha-1] was statistically analysed by two-way ANOVA including N-formand N-levels as treatment factors.Results and discussionNitrogen losses by NH3-volatilization differed between dates of fertiliser application. Figure 1shows the cumulative and the relative ammonia losses after biogas slurry application ongrassland determined in 3 experimental campaigns.Figure 1 Cumulative and relative N-loss by NH3-volatilization after application of biogasslurry in different N levels, perennial ryegrass (Lolium perenne), marsh region of Schleswig-Holstein, micrometeorological bLS-technique, 3 dates during spring and summer 2009.After N-application relative losses of about 20% of NH4-N applied could be observed on theapplication dates 7 April and 1 July, whereas on 28 May the NH3-losses were higher than30% of supplied NH4-N. The higher relative losses were probably due to strong wind on 28May, which is one of the main driving factors for NH3-volatilization. Average wind speed at aheight of 2 metres for the first few hours after application was 7.4 m s-1, much higher than on7 April (3.6 m s-1) and on 1 July (2.4 m s-1). NH3-volatilization losses after slurry applicationGrassland in a ChangingWorld269with trail hoses in the marsh were about two fold higher than in other landscapes ofSchleswig-Holstein(Pacholskiet al., 2009).The yield of ryegrass was significantly lower for every cut in the biogas slurry treatment ascompared to mineral fertilisation. No interaction between N fertiliser and N level wasobserved (Fig. 2).Figure 2 Dry matter yield [t ha-1] of perennial ryegrass, cut 4 times a year, at a moderate (360kg ha-1N) and a high level (480 kg ha-1) of N fertilization with biogas slurry (BGS) andmineral fertilizer (CAN) in the marsh region of Schleswig-Holstein. Values with differentletters are statistically different atP<0.05 (Tukey-test, n=4).As a result the total DM yield decreased from 14.5 t ha-1(CAN) to 8.5 t ha-1(BGS) by about42% under the lower N level, and from 17.3 t ha-1(CAN) to 10.4 t ha-1(BGS) about 40%under the high N level (Fig. 2). The data suggest that N-losses by NH3-volatilization were themain factor for high differences in yield levels between the two N-fertilisers. In addition,lower yields under biogas slurry fertilisation could also be due to ammonium adsorption andfixation in the soil characterized by high clay contents, N2O-losses by microorganisms or N-leaching. Besides environmental impact, like acidification and eutrophication, NH3-volatilization can thus also strongly influence the N-fertilisation value of biogas slurry.Nevertheless, a DM yield of 14.5 t ha-1for grass with mineral fertilisation was competitive tothe yield of dominant biogas crop maize at this site (average of 15 t ha-1).ConclusionFertilisation of biogas slurries with trail hoses can lead to high N-losses by NH3-volatilization.Losses were even higher than 30% of NH4-N applied, in situations with strong winds. Thoselosses substantially contributed to strongly decreased yields of perennial ryegrass and highenvironmental impact. In the study region, grasses cut 4 times a year can be considered as arealistic alternative to maize as substrate for biogas production due to similar dry matter yieldlevels.ReferencesPacholski A., Gericke D. and Kage H. (2009) Measurement and modelling of NH3 emissions from field-appliedbiogas residues in North German energy crop rotations. In: Grignani C., Acutis M., Zavattaro L., Bechini L.Bertora C., Marino Gallina P. and Sacco D. (eds.)Proceedings of the 16th Nitrogen Workshop - Connectingdifferent scales of nitrogen use in agriculture. 28th June – 1st July 2009, Turin, Facolta di Agraria, Turin, Italy,189-190.Sommer S.G. and Hutchings N.J. (2001) Ammonia emission from field manure and its reduction – invited paper,European Journal of Agronomy15, 1-15.Sommer S.G., McGinn S.M. and Flesch T.K. (2005) Simple use of the backwards Langrangian stochasticdispersion technique for measuring ammonia emission from small field-plots.European Journal of Agronomy23, 1-7.

KW - Ecosystems Research

M3 - Published abstract in conference proceedings

SN - 978-3-86944-021-7

T3 - Grassland science in Europe

SP - 268

EP - 270

BT - Grassland in a changing world

A2 - Schnyder, H.

A2 - Isselstein, J.

A2 - Taube, F.

A2 - Schellberg, J.

A2 - Wachendorf, M.

A2 - Hermann, A.

A2 - Gierus, M.

A2 - Auerswald, K.

A2 - Wrage, N.

A2 - Hopkins, A.

PB - Mecke Druck und Verlag

CY - Dudestadt

T2 - 23rd EGF General Meeting - EGF 2010

Y2 - 29 August 2010 through 2 September 2010

ER -