356-7 Plant Residue Addition Affects Soil Nitrous Oxide Emission Differently Between Aerobic and Oxygen-Limited Conditions.



Wednesday, October 19, 2011
Henry Gonzalez Convention Center, Hall C, Street Level

Xuechao Li1, Lei Tian1, Feng Hu2 and Wei Shi1, (1)Soil Science, North Carolina State University, Raleigh, NC
(2)Soil Science, Nanjing Agricultural University, Nanjing, China
Plant residue can be an important factor regulating the emission of greenhouse gases, such as nitrous oxide (N2O). We conducted an 84-d laboratory incubation to examine the effects of plant residues on soil N2O emission, microbial respiration and net N mineralization under aerobic (i.e., 30% and 60% water filled pore space (WFPS)) and oxygen-limited (i.e., 90% WFPS and fluctuation between 30% and 90% WFPS) conditions. Plant residues with C:N ratios ranging from 14 to 297 were added into a Wickham sandy loam soil collected from an organic farm at 4 mg C g-1 soil. Plant residue addition enhanced soil N2O emission by up to ~ 82% and 136% at 30% and 60% WFPS, respectively, but reduced soil N2O emission by up to ~ 90% and 95% at 90% WFPS and the fluctuation, respectively. These plant residue-associated effects appeared to be related to their C:N ratios. Enhancing effects at aerobic conditions were inversely related to the C:N ratios of plant residues; by contrast, the reducing effects at oxygen-limited conditions were positively related to the C:N ratios of plant residues. While plant residue addition has been considered to stimulate denitrification, thereby the production of nitrogen gases under oxygen-limited conditions, our results demonstrated that N2O emission was greatly reduced by plant residue addition.
See more from this Division: S03 Soil Biology & Biochemistry
See more from this Session: General Soil Biology & Biochemistry: II