ABSTRACT
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371 Atmospheric CO2 and Rice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371 Objectives of the Rice FACE Experiment . . . . . . . . . . . . . . . . . . . . . . 373
Growing Crops under Elevated [CO2]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 Chamber Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 FACE Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 Rice FACE System: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
Ring Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376 CO2 Control and Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376 Temporal and Spatial Control of [CO2] (1999) . . . . . . . . . . . . . . 377
The Effects of FACE on the Growth and Yield of Paddy Rice . . . . . . . . . . . 378 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
Conclusions and Implications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
INTRODUCTION
Atmospheric CO2 and Rice
It is estimated that up until the industrial revolution in the eighteenth century, atmospheric CO2 concentrations ([CO2]) were about 280 ppmV (parts
per million by volume). Since then, the [CO2] has risen to 370 ppmV at present and is expected to keep increasing at a rate of about 15 ppmV per decade. The increase in [CO2] is attributed to human activities such as fossil fuel burning and deforestation (Houghton et al., 1996). It is predicted that the increase will continue into the twenty-first century, resulting in a [CO2] concentration somewhere between 450 and 550 ppmV around the year 2050 (Houghton et al., 1996). Because CO2 is a “greenhouse” gas, the increase in [CO2] is predicted to affect the global radiation energy balance and thereby climate. The predicted changes in climate most notably include an increase in the Earth’s mean surface temperature and alterations in rainfall patterns, both factors which strongly affect biomass production in both agricultural and natural ecosystems worldwide (Reilly, 1996).
