Open AccessCarbon budget and methane and nitrous oxide emissions over the growing season in a Miscanthus sinensis grassland in Tomakomai, Hokkaido, Japan
Author(s) -
TOMA YO,
FERNÁNDEZ FABIÁN G.,
SATO SYOHEI,
IZUMI MIKI,
HATANO RYUSUKE,
YAMADA TOSHIHIKO,
NISHIWAKI AYA,
BOLLERO GERMÁN,
STEWART J. RYAN
Publication year - 2011
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/j.1757-1707.2010.01070.x
Subject(s) - miscanthus sinensis , environmental science , grassland , miscanthus , growing season , biomass (ecology) , agronomy , primary production , sink (geography) , greenhouse gas , ecosystem , bioenergy , biofuel , ecology , biology , geography , cartography
Species in the Miscanthus genus have been proposed as biofuel crops that have potential to mitigate elevated atmospheric carbon dioxide (CO 2 ) levels and nitrous oxide (N 2 O) and methane (CH 4 ) emissions. Miscanthus sinensis is widespread throughout Japan and has been used for biomass production for centuries. We assessed the carbon (C) budget and N 2 O and CH 4 emissions over the growing season for 2 years in a M. sinensis ‐dominated grassland that was naturally established around 1972 in Tomakomai, Hokkaido, Japan, which is near the northern limit for M. sinensis grassland establishment on Andisols. Average C budget was −0.31 Mg C ha −1 , which indicates C was released from the grassland ecosystem to the atmosphere. Dominant components in the C budget appeared to be aboveground net primary production of plants (1.94–2.80 Mg C ha −1 ) and heterotrophic respiration (2.27–3.11 Mg C ha −1 ). The measurement of belowground net primary production (BNPP) of plants in the M. sinensis grassland was extremely variable, thus only an approximate value could be calculated. Mean C budget calculated with the approximated BNPP value was 1.47 and −0.23 Mg C ha −1 for 2008 and 2009, respectively. Given belowground biomass (9.46–9.86 Mg C ha −1 ) was 3.1–6.5 times higher than that of aboveground biomass may provide additional evidence suggesting this grassland represents a C sink. Average CH 4 emissions across years of −1.34 kg C ha −1 would indicate this grassland acts as an atmospheric CH 4 sink. Furthermore, average N 2 O emissions across years were 0.22 kg N ha −1 . While the site may contribute N 2 O to the atmosphere, this value is lower compared with other grassland types. Global warming potential calculated with the approximated BNPP value was −5.40 and 0.95 Mg CO 2 Eq ha −1 for 2008 and 2009, respectively, and indicates this grassland could contribute to mitigation of global warming.