No abstract

Rice yield may be reduced substantially when the crop is exposed to the excessive heat predicted under future climate conditions, but the magnitudes of the yield losses under open-field conditions are difficult to predict. To better understand the occurrence of heat stress under field conditions, we established a network for monitoring the rice canopy thermal environment in paddy fields and for collecting other crop data (MINCERnet); the network initially covers eight of the world's rice growing regions. The relative humidity (RH), air temperature (T a) in nighttime, and amplitude of daily changes in T a differed greatly among sites, which are considered to affect panicle temperatures and rice reproduction. The T a difference between air above and inside the canopy varied depending on RH. T a at the weather station nearest to the respective field was higher than T a above the rice canopy. T a inside the canopy near the panicles was lower than T a above the canopy, but the magnitude of the difference varied among sites, because canopy cooling by evapotranspiration depended on the characteristics of the ambient environment and of the plant canopy. By recording data from different climate zones, MINCERnet will improve our quantitative understanding of the impacts of climate change on rice.