Journal
CANADIAN JOURNAL OF SOIL SCIENCE
Volume 88, Issue 2, Pages 133-143Publisher
CANADIAN SCIENCE PUBLISHING
DOI: 10.4141/CJSS06005
Keywords
denitrification; nitrous oxide; glucose; red clover; barley straw; carbon availability; terminal electron acceptor; aeration
Categories
Ask authors/readers for more resources
National inventories of N2O emissions from agricultural situations are being developed; however, the factors controlling such emissions may vary with soil and environmental conditions and management practices. This study determined the relative importance of soil aeration, as measured by water-filled pore space (WFPS), NO3- addition, C addition and C source on the amount and partitioning of gaseous N losses from denitrification from an arable soil in Atlantic Canada. Denitrification (N2O+N-2) and N2O emissions were measured on repacked soil cores using acetylene inhibition. The N2O:(N2O+N-2) ratio was frequently 0.7 or higher, indicating that most emissions occurred as N2O. N2O emissions and denitrification were negligible at a WFPS of 0.45 m(3) m(-3), and high at WFPS of 0.75 m(3) m(-3), regardless of NO3- or C addition treatments. At a WFPS of 0.60 m(2) m(-3), N2O emissions and denitrification were low and were increased by both NO3- and C addition treatments. Carbon source was investigated by amendment with glucose, red clover or barley straw. Based on the quantity of soil respiration per unit of C added in the amendment, C in the red clover and barley straw was estimated to be 48 and 28% as available as glucose C. When corrected for C availability, cumulative N2O emissions averaged 0.010, 0.011 and 0.002 mg N kg(-1) soil, and cumulative denitrification averaged 0.014, 0.014 and 0.003 mg N kg(-1) soil, for each 1.0 mg C kg(-1) soil of available C added as glucose, red clover or barley straw, respectively. NO3- addition had no effect on denitrification, but increased N2O emissions, especially where C availability was high. The amount of denitrification was controlled primarily by soil O-2 supply, as controlled by WFPS and C availability. The N2O:(N2O+N-2) ratio was generally high in cases where the supply of O-2 or NO3- was sufficient to meet the demand for terminal electron acceptors.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available