FACE条件下水稻冠层蒸散和水分利用率的模拟

Simulation of rice canopy evapotranspiration and water use efficiency under free-air CO_2 enrichment

利用开放式CO2浓度增高(FACE)系统平台,通过在水稻拔节期至成熟期对水稻冠层微气候及相关生理指标的连续观测,并结合能量平衡分析,模拟研究了FACE对水稻冠层蒸散和水分利用率的影响.结果表明:将水稻叶片气孔导度与光合有效辐射、饱和水气压差的定量关系与Penman-Monteith方程相结合,可以较好地模拟FACE和对照条件下的水稻蒸散量;观测期间,CO2浓度升高使水稻的水分利用比对照减小约10mm,结合水稻生物量增加12%,FACE条件下水稻水分利用率(WUE)增加约12%.

By using FACE system, the microclimate in rice canopy and related physiological indices were observed continuously from the elongation to the maturing stage of rice growth, and the effects of FACE on the rice canopy evapotranspiration and water use efficiency were studied and simulated with energy balance analysis. The results showed that using P-M equation to describe the quantita- tive relationships of rice leaf stomatal conductance with photosynthetically active radiation （PAR） and vapour pressure deficit （VPD） could better simulate rice canopy evapotranspiraton under FACE and ambient conditions. During observation period, the total water use of rice in FACE plot had a 10 mm decrease, compared with that in control plot. Considering of the 12% increase of total biomass, the water use efficiency of rice under FACE condition was increased by 12%.