2012 Volume 68 Issue 2 Pages 135-147
To understand the growth impairment caused by heat stress in rice, it is necessary to continuously monitor panicle temperatures (Tp), as the panicles are the organs most susceptible to heat stress. However, these measurements require elaborate measurement systems and time-consuming work, making it difficult for agronomists to obtain the necessary data. As a practical alternative, we focused on the air temperature (Ta) around the panicle, which is easier than Tp to measure and closer to Tp than the air temperature observed at weather stations, which are usually distant from the study sites. Because most commercially available meteorological instruments are not well packaged for use within a rice canopy, special knowledge is required for their installation. Another problem is the difficulty in supplying power to the equipment, because electricity is rarely available in a rice paddy. To overcome these difficulties, we developed MINCER (Micrometeorological Instrument for the Near-Canopy Environment of Rice), a radiation-shielded, solar-powered, force-ventilated system that is packaged to facilitate its use by researchers. Tests of MINCER in open fields showed that its performance for Ta is comparable to those of the devices used at Japanese meteorological observatories, if properly calibrated. Tests in a rice community showed that MINCER outperforms a naturally ventilated device. Although Ta, which is observed to represent general surface weather conditions at local stations, often does not reflect the micrometeorological conditions within the rice canopy, MINCER can provide these data at an affordable cost.
