Winter‐Season Gaseous Nitrogen Emissions in Subtropical Climate: Impacts of Pig Slurry Injection and Nitrification Inhibitor. Issue 5 (11th July 2019)

• Record Type: Journal Article
• Authors: Aita, Celso; Chantigny, Martin H.; Gonzatto, Rogério; Miola, Ezequiel C.C.; Rochette, Philippe; Pujol, Stefen B.; dos Santos, Daniela B.; Giacomini, Diego A.; Giacomini, Sandro J.
• Is Part Of: Journal of Environmental Quality. Volume 48:Issue 5(2019)
• Page Start: 1414
• Page End: 1426
• Publication Date: 2019-07-11
• Subjects: DCD, dicyandiamide -- EF, emission factor -- IPCC, Intergovernmental Panel on Climate Change -- PS, pig slurry -- PSi, injection of pig slurry -- PSs, surface broadcast of pig slurry -- WFPS, water‐filled pore space; Agricultural ecology -- Periodicals; Environmental engineering -- Periodicals; Pollution -- Periodicals; 630
• DOI: 10.2134/jeq2018.04.0137
• Languages: English
• ISSNs: 0047-2425

Abstract

Abstract : Controlling nitrogen (N) losses from pig slurry (PS) is a challenge under no‐till because amendments are left on the soil surface. We investigated the potential of shallow injection of PS, with and without addition of the nitrification inhibitor dicyandiamide (DCD), to abate gaseous ammonia (NH3 ) and nitrous oxide (N2 O) emissions in winter crops in subtropical soils. Injection was compared with surface broadcasting of PS, with and without DCD. The significance of winter season on annual N2 O emissions was assessed. Injecting PS reduced NH3 volatilization compared with surface application. However, this reduction was partly offset because N2 O emissions increased by 77% (+1.53 kg N2 O‐N ha −1 ) when PS was injected. Adding DCD to injected PS reduced N2 O emission below levels of surface‐broadcast PS without the inhibitor, indicating that DCD may be a management option when injecting PS. Compared with a reference urea treatment, PS without DCD increased cumulative N2 O emissions 5.7‐fold (from 613 to 3515 g N2 O‐N ha −1 ) when injected, and 3.2‐fold (from 613 to 1980 g N2 O‐N ha −1 ) when surface applied. Adding DCD significantly reduced emissions with injected PS, whereas reduction was not always significant with surface‐applied PS. Nitrous oxide emissions during the winter cropping season contributed 30 to 44% of annual emissions, indicating that controlling gaseous N losses in that season is required to reduce the environmental footprint of the whole cropping system. Overall, combining PS injection with DCD was an efficient practice for reducing winter‐season gaseous N losses from no‐till soils under subtropical climate. Core Ideas: Winter‐season NH3 and N2 O were measured after pig slurry additions to no‐till soils. N2 O emissions during the winter season contributed 30 to 44% of annual emissions. Shallow injection of pig slurry reduced NH3 volatilization but increased N2 O emissions. DCD added to pig slurry more than offset the increase in N2 O emissions with injection. Pig slurry injection combined with DCD reduces gaseous N losses in subtropical soils.