Abstract

Authors

KOSUGI Yoshiko, OSAKA Ken'ichi, ITOH Masayuki, TAKANASHI Satoru, MATSUBARA Takashi

Year

2010

Title

Photosynthesis and respiration of managed C₃ turfgrass fields under various light conditions

Journal

Journal of Agricultural Meteorology

Volume

66(3)

Page

163-171

DOI

10.2480/agrmet.66.3.2

Keywords

Ecosystem respiration, Gas flux chamber, Low irradiance, NEE, Stadium

URL

http://www.jstage.jst.go.jp/article/agrmet/66/3/66_163/_article

Abstract

Net ecosystem CO₂ exchange from managed C₃ turfgrass (Kentucky bluegrass, Poa pratensis) fields under various light conditions (irradiance level of 100, 60, 49, 20%) was measured with the closed dynamic chamber method from spring to fall. Net ecosystem CO₂ exchange was measured in situ using a 'clear' chamber, and total ecosystem respiration rate was measured using a 'dark' chamber. Both respiration rate and the amount of biomass were smaller in the shaded plots. Ecosystem respiration normalized with respect to soil temperature decreased in summer, coinciding with the seasonal change in plant biomass. The amount and seasonal change of biomass, not temperature, mainly governed the ecosystem respiration of the C₃ turfgrass fields under various light conditions. The light curve of gross photosynthesis, which was calculated by adding the respiration rate to net ecosystem exchange at each measurement time, was compared between plots. There were no obvious differences between plots in the response of gross photosynthesis to light in spring, and a decline of the maximum photosynthesis at an optimal irradiance was observed in summer, except in the darkest plot.

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