Vol15 No.9: 1972-1986
【Title】Crop residue incorporation and nitrogen fertilizer effects on greenhouse gas emissions from a subtropical rice system in Southwest China
【Author】WANG Xiao-guo1*; LUO Yong2
【Addresses】1 Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 2 Key laboratory of Geological Spatial information Technology of Ministry of Land and Resource, Chengdu University of Technology, Chengdu 610059, China
【Corresponding author】WANG Xiao-guo
【Citation】Wang XG, Luo Y (2018) Crop residue incorporation and nitrogen fertilizer effects on greenhouse gas emissions from a subtropical rice system in Southwest China. Journal of Mountain Science 15(9). https://doi.org/10.1007/s11629-017-4810-4
【Abstract】Crop residue incorporation has been widely accepted as a way to increase soil carbon (C) sequestration and sustain soil fertility in agroecosystems. However, effect of crop residue incorporation on greenhouse gas (GHG) emissions in rice paddy soils remains uncertain. A field experiment was conducted to quantify emissions of CH4 and N2O and soil heterotrophic respiration (RH) from a paddy rice field under five different crop residue treatments (i.e., 150 kg N ha-1 of synthetic N fertilizer application only [NF], 150 kg N ha-1 of synthetic N fertilizer plus 5.3 Mg ha-1 wheat residue [NF-WR1], 150 kg N ha-1 of synthetic N fertilizer plus 10.6 Mg ha-1 wheat residue [NF-WR2], 75 kg N ha-1 of synthetic N fertilizer plus 10.6 Mg ha-1 wheat residue [50%NF-WR2] and 150 kg N ha-1 of synthetic N fertilizer plus 21.2 Mg ha-1 wheat residue [NF-WR3]) in southwest China. Our results showed that crop residue incorporation treatments (NF-WR1, NF-WR2, 50%NF-WR2, NF-WR3) significantly increased CH4 emissions by at least 60%, but N2O emissions were not enhanced and even suppressed by 25% in the NF-WR3 treatment as compared to the NF treatment. Soil RH emissions were comparable among experimental treatments, while crop residue incorporation treatments significantly increased soil carbon sequestrations relative to the NF treatment. Overall, CH4 emissions dominated total global warming potentials (GWP) across all experimental treatments. The average yield-scaled GWPs for the NF and NF-WR1 treatments were significantly lower than for the NF-WR2, 50%NF-WR2 and NF-WR3 treatments. Given the comparable yield-scaled GWPs between the NF and NF-WR1 treatments, the NF-WR1 treatment could gain net carbon sequestration as compared with the NF treatment with net soil carbon loss. Our findings suggest that the NF-WR1 treatment should be an effective option to sustain rice production while mitigating GHG emissions from the rice field in China.
【Keywords】Methane; Nitrous oxide; Crop residue; Soil carbon sequestration; Global warming potential; Paddy field