Emissions of N2O and CO2 Following Short-Term Water and N Fertilization Events in Wheat-Based Cropping Systems

Abstract

Greenhouse gas (GHG) emissions result from short-term perturbations of agricultural systems such as precipitation and fertilization events. We hypothesized that those agricultural systems with contrasting management histories may respond differently to application events of water and N fertilizer with respect to GHG emissions. Studies with long-term management histories consisting of no-tillage (NT) and conventional tillage (CT) were coupled with high temporal resolution, automated chambers that monitored N 2 O and CO 2 emissions for 22 h following treatments. Treatments applied to NT and CT were (a) control (no water or N additions), (b) simulated precipitation to achieve approximately 80% water-filled pore space, and (c) precipitation plus fertilizer additions of 150 kg N ha −1 as ammonium nitrate. Emissions of CO 2 increased with increase in moisture and temperature and decreased under fertilizer application. Water and nitrogen treatments in CT at the sites with 2 and 12-year history produced N 2 O fluxes greater than NT by 142 and 68%, respectively. The site with 10-year history of NT produced similar amounts of N 2 O from CT and NT treatments. The same treatments at the site with 31 year-long NT history, despite being one of the lowest among all sites, demonstrated 380% higher N 2 O fluxes from the NT than CT, which was likely due to higher levels of labile organic matter present in NT treatments. GHG emissions data regressed on measured soil C and N properties, fractionation, and mineralization data showed that N 2 O flux increased with reduction of acid-hydrolyzable N and increase of NH 4-N in soil, which suggested that N 2 O production in the short-term water and water and N additions events is mostly produced via nitrification process. This indicates that neither the length of NT treatment nor the fertilizer application rate define the rate of N 2 O emissions, but the soil N availability controlled by organic matter mineralization rate. The current study demonstrates the need for further research on the effects of the early stages of NT adoption as well as long-term NT on N 2 O spikes associated with artificial or natural rainfall events immediately following extended dry periods.

Biochar impacts on nutrient dynamics in a subtropical grassland soil: 2. Greenhouse gas emissions

“…The significant ( P < .0001) positive correlation ( r = .29) between N 2 O and CO 2 emissions observed in the current study is consistent with previous studies (Alluvione et al., 2010; Kostyanovsky, Huggins, Stockle, Morrow, & Madsen, 2019). Increased soil respiration might reduce soil oxygen availability and lead to anaerobic conditions within soil microsites, thereby favoring denitrification (Alluvione et al., 2010; Baah‐Acheamfour, Carlyle, Lim, Bork, & Chang, 2016).…”

A mass spectrometric multiple soil-gas flux measurement system with portable high-resolution mass spectrometer MULTUM coupled to automatic chamber for continuous field observation

“…8). Various studies have reported increased N2O flux after rainfall (Nobre et al, 2001;Dobbie and Smith, 2003;Smith and Owens, 2010;Gelfand et al, 2015;Schwenke and Haigh, 2016;Leitner et al, 2017;Barba et al, 2019;Kostyanovsky et al, 2019) and similar increased CO2 flux after rainfall has been reported (Lee et al, 2002;Smith and Owens, 2010;Gelfand et al, 2015;Kostyanovsky et al, 2019). However, no short-term responses of CO2 and N2O fluxes, similar to our observation upon rainfall, were reported.…”

“…In the present laboratory test, CO2 and N2O fluxes showed different temporal behaviors from those observed by Kostyanovsky et al (2019), although observed N2O flux change was similar to that observed by Leitner et al (2017). We currently speculate that the slow increase in N2O flux may reflect a slow building-up of nitrification and denitrification microorganisms after watering, although further studies, which apprehend both biological and physicochemical aspects of the soil gas formations, are necessary for better understanding.…”

“…Such increases in soil CO2 flux by rainfall or rewetting soil have been reported (Lee et al, 2002;Smith and Owens, 2010;Gelfand et al, 2015;Kostyanovsky et al, 2019), and enhanced microbial activity and population, boosted availability in carbon and nutrients by rewetting, or their assemblages are considered as possible causes (Fierer and Schimel, 2003;Iovieno and Bååth, 2008;Blazewicz et al, 2014). Similar N2O flux increase upon rewetting soil have been reported (e.g., Nobre et al, 2001; Dobbie and Smith, 2003;Smith and Owens, 2010;Gelfand et al, 2015;Schwenke and Haigh, 2016;Leitner et al, 2017;Barba et al, 2019;Kostyanovsky et al, 2019), although very few research reported the simultaneous response of N2O and CO2…”

“…fluxes upon artificial watering (Smith and Owens, 2010;Gelfand et al, 2015;Kostyanovsky et al, 2019). continued till about 3 h after the simulated rainfall, while that in N2O flux continued till about 5 h after the simulated rainfall.…”