Application Technique and Slurry Co‐Fermentation Effects on Ammonia, Nitrous Oxide, and Methane Emissions after Spreading

Abstract

Ammonia emissions after spreading animal manure contribute a major share to N losses from agriculture. There is an increasing interest in anaerobic co-digestion of liquid manure with organic additives. This fermentation results in a change of physical and chemical parameters of the slurry. Among these are an increased pH and ammonium content, implying a higher risk of NH3 losses from fermentation products. To compare different application techniques and the effect of fermentation on NH3 volatilization, we used the standard comparison method and tested it for reliability. This method seems to be perfectly suited for experiments with a large number of treatments and replicates if prerequisites concerning the experimental layout are considered. We tested four different application techniques on arable and grassland sites. The more the substrate was incorporated into the soil or applied near the soil surface on the grassland site, the less NH3 was lost. Injection of the substrate reduced losses to less than 10% of applied NH4+ on both sites, whereas losses after splash plate application amounted to more than 30%. Trail shoe application on grassland performed as well as injection. Harrowing on arable land also reduced emissions efficiently, if harrowing occurred within the first 2 h after application. Emissions from trail hose-applied co-fermentation product were not greater than from unfermented slurry. Better infiltration of the less viscous substrate seemed to have compensated for the increased loss potential.

Effects of anaerobic digestion on soil carbon and nitrogen turnover, N emissions, and soil biological activity. A review

“…However, digestion leads simultaneously to an increase in manure pH (by 0.5-2.0 U) and of the ammonium concentration (relative increase of >20 %) (Möller and Müller 2012); both factors promote N losses via NH 3 volatilization (e.g., Gericke et al 2012;Ni et al 2012;Sommer and Hutchings 2001 In concordance with the described potential effects, contradictory results regarding the effects of anaerobic digestion on NH 3 volatilization after field application of digestates have been reported in literature: Some researchers report a decrease of NH 3 losses after soil application of digested animal manures, others report an increase of losses, and others did not found any or ambiguous effects (Table 3). Other research groups compared volatilization after spreading of undigested slurry and a digestate derived from slurry plus other feedstocks (e.g., Wulf et al 2002a;Ni et al 2012), an approach which do not allow for the assessment of the effect of anaerobic digestion itself on NH 3 volatilization, requesting for a careful interpretation of the results. In some reports, digestates were used which lost considerable amounts of N during the digestate storage, a situation which does not match with the current state of the art (Table 3), and probably reduced the NH 3 losses after digestate field spreading.…”

Inibidor de nitrificação e aplicação parcelada de dejetos de suínos nas culturas do milho e trigo

“…A incorporação e a injeção dos dejetos no solo podem reduzir a volatilização de NH 3 em pelo menos 90 % (Webb et al, 2010), embora essas possam aumentar as perdas de N por desnitrificação (Wulf et al, 2002). O uso de inibidores de nitrificação no momento da aplicação dos dejetos pode reduzir as emissões de N 2 O (Vallejo et al, 2005;Damasceno, 2010), que podem ocorrer tanto durante a nitrificação do N amoniacal dos dejetos quanto durante a desnitrificação (Arcara et al, 1999).…”

Impact of chemically amended pig slurry on greenhouse gas emissions, soil properties and leachate

“…After land application, CH 4 emissions are generally of minor importance compared to N 2 O emissions (Wulf et al, 2002a(Wulf et al, , 2002b, as CH 4 emissions from enteric fermentation and during slurry storage are much more important (Chadwick et al, 2000). This is due to CH 4 being produced by decomposition of OM in faecal matter under anaerobic conditions.…”