NH₃ and N₂O Emissions after Landspreading of Slurry as Influenced by Application Technique and Dry Matter‐Reduction. I. NH₃ Emissions

Abstract

Summary -ZusammenfassungAmmonia volatilization from slurry is undesirable because of environmental N eutrophication and loss of fertilizer value. The dry matter content of slurry, the application technique and the weather conditions are the main factors influencing NH, losses from landspread slurry. In a field of winter wheat a two factor plot experiment was conducted to study single and combined effects of slurry separation and application techniques, including broadcast and banded application, as well as incorporation by injection and the flexible harrow. Ammonia volatilization from all treatments could be measured simultaneously, and at ambient climatic conditions by an indirect, open measurement technique. The experiment was repeated four times. Due to varying weather conditions and treatment effects, cumulative NH, volatilization from the slurry during the first 48 hours ranged from 4 to 90% of total ammoniacal nitrogen (TAN). Both separation and incorporation significantly decreased NHJ losses, but only the combination of dry matter reduction and injection or harrowing reduced NH, volatilization to about 30% ofTAN in all weather conditions. Banding alone did not efficiently conserve slurry N, but even enhanced NH, volatilization in wet conditions.

The annual ammonia budget of fertilised cut grassland – Part 1: Micrometeorological flux measurements and emissions after slurry application

“…It has been found by numerous previous studies that low dry matter content reduces ammonia losses (e.g. Pain et al, 1989;Vandre et al, 1997;Misselbrook et al, 2005b), and there are several reports on NH 3 losses after slurry spreading by splash plates with emission factors lower than 20% (Braschkat et al, 1997;Misselbrook et al, 2005a;Rochette et al, 2008) or even 10% (Misselbrook et al, 2004) of applied TAN. Most of these low emission observations were associated with spreading of pig slurry (partly diluted) with low dry matter contents, albeit of similar magnitude as the manure applied here.…”

Determination of field scale ammonia emissions for common slurry spreading practice with two independent methods

“…The analyser was run continuously during the experimental period to monitor NH 3 background levels recording data in 3 s intervals. In field measurements, a setup including a comparable instrument had an effective time resolution of roughly 5 to 10 min (von Bobrutzki et al, 2010). In the present study, the recorded NH 3 concentration were averaged over 10 min.…”

“…Analytical difficulties in NH 3 measurements may originate from gas-phase calibration uncertainties (von Bobrutzki et al, 2010), drifting instrumental stability , selective sampling and analysis of gas and aerosol phase and NH 3 sorption in filters, tubes and devices (Parrish and Fehsenfeld, 2000). Flux measurements with the aerodynamic gradient method using AMANDA instruments are associated with uncertainties of 20 % to 76 % (Sutton et al, 2000;Milford et al, 2009).…”

“…The different biases observed in the two fertilisation events might be attributed to shifting instrumental performance. For example, in a recent intercomparison, von Bobrutzki et al (2010) characterised eleven state-of-the-art instruments for NH 3 concentration measurements based on eight analytical methods. Agreements better than 25 % can hardly be achieved and deviations can be much larger.…”

“…Pain et al, 1989;Braschkat et al, 1997;Génermont et al, 1998;Menzi et al, 1998;Huijsmans et al, 2001;Søgaard et al, 2002;Huijsmans et al, 2003;Misselbrook et al, 2002Misselbrook et al, , 2005aSanz et al, 2010;Spirig et al, 2010;Uusi-Kämppä and Mattila, 2010). The strong stickiness of the polar NH 3 molecule complicates measurements of ambient NH 3 concentrations (Parrish and Fehsenfeld, 2000;von Bobrutzki et al, 2010) and consequently fluxes. Varying instrumental performance Sutton et al, 2009) and limited signal range of sensors introduce large uncertainties into NH 3 emission quantifications.…”