Effect of different N rates and use of DMPP on N 2 O emissions from wheat and maize in sub tropical Ferrosols Massimiliano ili De Antoni imigliorati Institute for Future Environments Queensland University of Technology
Climate Change & Agriculture N 2 O 8% of global anthropogenic CO 2 eq emissions Also involved in the depletion of the ozone layer Agricultural systems: 6 to 77% of total human derived N 2 O emissions (IPCC, 27; US EPA, 26) IPCC, 27
Climate Change & Agriculture N 2 O 8% of global anthropogenic CO 2 eq emissions Also involved in the depletion of the ozone layer Agricultural systems: 6 to 77% of total human derived N 2 O emissions (IPCC, 27; US EPA, 26) so why to target N 2 O emissions from agriculture to reduce GW? Increasing emissions (+.26% per year, IPCC, 27) High GWP (296 CO 2 eq) Plenty of room for intervention! IPCC, 27
Climate Change & Agriculture N 2 O emissions from agriculture: the case of Cereal production Positive correlation N 2 O emissions N fertilization rates (Del Grosso, 26; Bouwman et al.,22) Worldwide: 6% of N fertilizer is employed to grow cereals (Maize, Rice, Wheat) Australia: Receive > synthetic nitrogen fertilizer within all crops (Australian Gov.)
Climate Change & Agriculture N 2 O emissions from agriculture: the case of Cereal production Positive correlation N 2 O emissions N fertilization rates (Del Grosso, 26; Bouwman et al.,22) Worldwide: 6% of N fertilizer is employed to grow cereals (Maize, Rice, Wheat) Australia: Receive > synthetic nitrogen fertilizer within all crops (Australian Gov.) Higher productivity to feed + 3% World s population forecasted by 25 (UNFPA, 211) Increase N fertilizer use + 5% N 2 O emissions from agricultural activities forecasted by 22 (US EPA, 26)
Climate Change & Agriculture Need for sustainable intensification of cereal cropping systems Increase NUE of cereal crops & reduce N losses (N 2 O) Optimal N rates Enhanced Efficiency Fertilisers Nitrification Inhibitors (DMPP )
Hypothesis & Aims Main hypothesis of the research Appropriate N rates & use of DMPP Nitrification Inhibitor can improve cereal NUE and reduce N 2 O emissions Aims of the Project 1. Quantify impact of optimal N rates & use of DMPP Nitrification Inhibitor on N 2 O emissions and grain yield 2. Determine feasible mitigation strategies to reduce N 2 O emissions and improve NUE in subtropical cereal systems
Methodology Kingaroy SE Queensland Brown Ferrosols Subtropical Climate 2 monitoring campaigns Winter 211 Wheat Summer 211/212 / Maize 4 treatments L1 L2 L3 L4 = = = = control test sub optimal p fert. rate conv. Urea optimal N rate conv. Urea optimal N rate DMPP Urea plots fullyy irrigated g All p N2O fluxes Measured with automated GHG measuring system Closed chamber technique
Results Daily N 2 O fluxes Winter Season Wheat N O N Flux [g ha 1 d 1 2 ] 5 4 3 2 1 Rainfall/Irrigation (mm) L1 N L2 2N L3 8N L4 8N (DMPP) 1 9 8 7 6 5 4 3 Rain n/irrigation [mm m] 2 1 1 2 Jul Aug Sep Oct Nov N 2 O emission pulses after fertilization & irrigation events Little differences among treatments (low T inhibited bacteria activity)
Results N 2 O fluxes Winter Season Wheat Measurements Treatment L1 (N) L2 (2N) L3 (8N) L4 (8N DMPP) Cumulative N 2 O Flux [kg N ha 1 season 1 ].84±.6 a.62±.5 b 1.5±.9 c.75±.5 b Emission Factor [%] entire season*.19.9.5 Grain yield [t ha 1 ] 4.4±.6 a 5.1±.2 a 5.8±.2 a 5.5±.2 a N 2 O intensity [kg N 2 O N t yield 1 ].19.12.18.14 12 7 *corrected for background emissions of N 2 O N from the N treatment 1 6 g N 2 O N ha 5 1Cumulative 8 emission 4 6 3 4 2 2 1 t grain /ha Yield IPCC: 1% = 138 kg CO 1 2 eq ha 1 L1 N L2 2N L3 8N L4 8N (DMPP)
Results N O N Flux [g ha 1 d 1 2 ] Daily N 2 O fluxes Summer season Maize 25 2 15 1 5 Rainfall/Irrigation (mm) L1 4N L2 1N L3 16N L4 16N (DMPP) 9 8 7 6 5 4 3 m] in/irrigation [m Ra 2 1 5 Dec Jan Feb Mar Apr May Jun Pronounced differences among treatments > N Fertilizer inputs > Soil Temperature > Soil Moisture
Preliminary results N 2 O fluxes Summer Season Maize Measurements Treatment L1 (4N) L2 (1N) L3 (16N) L4 (16N DMPP) Cumulative N 2 O Flux [kg N ha 1 season 1 ].95 ±.11 a 2.28±.16 b 4.99±.52 c 1.7±.15 d Emission Factor [%] entire season* 1.33 2.52.47 Grain yield [t ha 1 ] 2.6±.2 a 6.1±.4 b 8.5±.2 c 8.4±.3 c N 2 O intensity [kg N 2 O N t yield 1 ].37.38.58.2 6 5 9 8 7 *corrected for background emissions of N 2 O N from the L1 treatment g N 2 O N ha 1 4 3 2 6 5 4 3 t grain /ha Cumulative emission 1 2 1 Yield = 153 kg CO 2 eq ha 1 L1 4N L2 1N L3 16N L4 16N (DMPP)
Results N 2 O cumulative fluxes 6 L1 N 5 L2 2N N 2 O Emissions in 8N (Urea) in winter < 4N (Urea) in summer Winter Wheat Flux [g ha 1 ] N 2 O N 4 3 2 L3 8N L4 8N (DMPP) 1 Jul Aug Sep Oct Nov 6 L1 4N 5 L2 1N Summer Maize a 1 ] N 2 O N Flux [g h 4 3 2 L3 16N L4 16N (DMPP) 1 Dec Jan Feb Mar Apr May Jun
Conclusions 14 th September 212 High variance of N 2 O emissions among seasons Scope for DMPP to significantly ifi reduce N 2 O losses only in summer ( > N rates, T, water) If DMPP urea included among strategies to reduce N 2 O emissions, Governmental incentive policies should focus on stimulating its use on summer cereal crops Extra Cost of fertilizing Maize with DMPP urea = AU$ 39 ha 1 Income from Carbon trade = 153 kg CO * 1 1 2 eq AU$ 23 t CO 2 = AU$ 35 ha Future research questions Can > crop NUE due to DMPP be used to reduce N rates without affecting yields? Further decrease N 2 O emissions due to lower soil N content Additional savings due to reduced fertilizer costs
14 th September 212 Questions? max.deantonimigliorati@qut.edu.au