Die Bodenkultur - Journal for Land Management, Food and Environment

G. Moitzi, V. Kryvoruchko, B. Amon, C. Wagner-Alt, T. Amon and J. Boxberger:

Effect of interval aeration on NH3-, N2O- and CH4 emissions during storage and application of pig slurry


Aeration of slurry is an aerobic treatment, where ammonia- (NH3), nitrous oxide- (N2O), methane- (CH4) and carbon dioxide- (CO2) emissions occur during storage and after application of slurry. Under field conditions the trace gases were collected with a mobile open-dynamic-chamber and were continuously analyzed with a high resolution FTIR spectrometer. Untreated pig slurry was stored under winter and under summer conditions in concrete tanks (á 12.3 m3). The aeration in one concrete tank was done with a submerged pump which was time-interval operated. After the measurement period for storage (more than 100 days) the slurry was band applied to grassland, where the emissions were also measured. The aeration of slurry caused an increase of slurry temperature up to 36.8 °C and an intensive foam formation. The maximum aeration intensity was limited by foam formation. Aerobic decomposition of organic matter caused in comparison to untreated slurry higher emissions of NH3, N2O, CH4 and CO2 during storage as well as during and after application. The denitrifying microorganisms in the intervally aerated slurry had optimal milieu conditions for N2O formation, which explains the high N2O emissions. For reasons of high emissions of environmental and climate relevant trace gases the interval-aeration of slurry can not be recommended for commercial farms. Key words:  Aerobic slurry treatment, trace gas emissions, open dynamic chamber method, manure treatment.