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Volume 69, Issue 3
Displaying 1-12 of 12 articles from this issue
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Full Paper
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Shinichi TAKAMI, Tetsuo SAKURATANI, Takeshi HORIE2013 Volume 69 Issue 3 Pages 101-108
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
Advance online publication: June 18, 2013JOURNAL FREE ACCESSEvapotranspiration (ET) rates from irrigated rice differ across environments and cultivars. To quantify these differences, we developed a computational model for prediction of crop ET of irrigated rice from meteorological variables and crop parameters. The model was based on a generalized combination formula and a stomatal response function derived from a controlled environment. Model predictions compared favorably with ET rates from crops measured by microlysimetry. Using this model, we simulated ET rates from hypothetical rice crops under different climatic conditions. Regardless of cultivars and leaf area index (LAI), all the crops demonstrated higher ET rates relative to the potential in a humid temperate climate than in an arid tropical climate. Strong winds generally prevailing in a tropical dry climate make stomatal control of ET in this climate more significant than that in a calm temperate climate. Furthermore, a cultivar with smaller minimum crop resistance (Rmin) always evaporated at a higher rate than a cultivar with larger Rmin when the same atmospheric demand was imposed. Such a difference was more distinct in the dry tropical conditions than in the humid temperate conditions. These findings agree with observations so far reported for irrigated rice. Thus, we conclude that our numerical model is capable of accounting for the effects of cultivars and environments on ET rates from irrigated rice.View full abstractDownload PDF (775K) -
Keiichi SATO, Yoshitaka KUROSE2013 Volume 69 Issue 3 Pages 109-115
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSA new method to evaluate the influence of fog on the pattern of normalized temperature from predawn to noon was developed. An S-shaped approximation function was used to characterize the temperature course. One parameter of this S-shaped function, α, can be used to detect places where the rise in air temperature is delayed. The relationship between α and fog occurrence was analyzed. Three findings were identified as follows. Foremost, a positive correlation was found between the number of days in November with fog and the values of α during each November. Secondly, α is strongly related to the visibility conditions after sunrise. Finally, α is large for observation points where fog occurs quite frequently during autumn, such as in Miyoshi, Hiroshima, Japan.View full abstractDownload PDF (817K) -
Hiromitsu KANNO, Masahiro WATANABE, Eiji KANDA2013 Volume 69 Issue 3 Pages 117-125
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSCold northeasterly winds, called Yamase, which cause the summertime weather of northern Japan to be unusually cool, have often damaged the rice crop in northern Japan, both historically and recently. To estimate future Yamase event occurrences, we used the new version of the MIROC5 atmosphere-ocean general circulation model and predicted the frequency of future Yamase events from the pressure difference index (pressure difference between Wakkanai and Sendai; PDWS). In a 20th-century experiment (1980-2005), the PDWS simulated by the MIROC5 model reproduced well the Yamase events in the JRA-25 reanalysis data. In a future climate experiment (2006-2100), the predicted occurrence frequency of Yamase events is low around the 2030s and from the 2080s onward, but in other periods, Yamase events are predicted to occur at about the same frequency as during the 20th-century experiment (1980-2005). Therefore, even under global warming, Yamase winds can be expected to affect agriculture in northern Japan in the 21st century.View full abstractDownload PDF (1452K) -
Aiko FUJII, Masahiro TASUMI2013 Volume 69 Issue 3 Pages 127-134
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSEvapotranspiration (ET) is one of the key factors in the planning and management of irrigation water resources. Accurate estimation of ET enables better irrigation planning, scheduling, and performance evaluation of water. As a fundamental study for developing a global ET estimation method, the performance of a thermal-based crop coefficient technique to estimate regional evapotranspiration in irrigated agricultural fields was examined. The study area was the Magic Valley irrigated agricultural region in southern Idaho, USA. Landsat surface temperature images were used as input data. ET in the main cultivation season (March to October) of the year 2000 was estimated using a thermal-based crop coefficient technique, and the performance of the technique was evaluated by comparing the outputs of the METRIC energy balance model. The root mean square difference in seasonal ET was 76 mm, which was equivalent to 7% of the reference ET. The performance of the thermal-based crop coefficient technique showed some differences according to the crop type. The thermal-based crop coefficient method provides reasonable ET information on a regional scale. With a simple structure and minimum requirement of input data, it was evaluated throughout this study that the method has potential for application on a global scale. Some important characteristics of the key temperature parameters in the method were also identified throughout this research. The findings are useful in future automation of the estimation procedure, which is necessary upon applying the method on a global scale.View full abstractDownload PDF (732K) -
Cattleya CHUTTEANG, Prathomrak NA-NGERN, Masatoshi AOKI, Shiro HATAKEY ...2013 Volume 69 Issue 3 Pages 135-145
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
Advance online publication: July 10, 2013JOURNAL FREE ACCESSCrop response to future air pollution stress is important information for crop production in the future. Ozone (O3) and peroxides are recognized as significantly damaging air pollutants to plants. Therefore, the present research aimed to investigate the single and combined effects of O3 and peroxides on leaf injury and physiological responses, and to compare the soybean cultivar sensitivities under exposure to single O3 and combined O3 and peroxides. Two Japanese soybean cultivars, Tachinagaha (TC), and Chamame (CM) and two Thai soybeans, A75 and Sorjor 5 (SJ5) were selected as plant materials. Four treatment plots were set up, including a control plot (C plot: free O3 and peroxides), O3 50 ppbv (O plot), O3 50 ppbv and peroxides 2-3 ppbv (OP1 plot) and O3 50 ppbv and peroxides 4-5 ppbv (OP2 plot). We found that combined O3 and several ppbv peroxides (OP2 plot) caused more severe damage than the OP1 plot and single O3 (O plot) to leaf injury, chlorophyll content and photosynthetic rate, and reduced total dry weight and pod dry weight. In combined O3 and peroxides exposure, SJ5 showed the most sensitive cultivar in leaf injury, photosynthetic rate, biomass and pod dry weight, while CM showed less sensitivity for photosynthetic rate and pod dry weight.View full abstractDownload PDF (1080K) -
Taichi MAKI, Osamu MORITA, Yoshinori SUZUKI, Kenji WAKIMIZU2013 Volume 69 Issue 3 Pages 147-157
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSThis experiment of artificial rainfall was carried out by an aircraft seeding operation of liquid carbon dioxide on Feb. 26-27, 2012, near Miyake Island of the Izu Islands in Tokyo, Japan. The development of convective clouds was significant after 0.5 to 1 h of the seeding near Miyake Island and reached to the heights of 3000 m and 4000 m on Feb. 26 and 27, respectively. Artificial clouds appeared and rain was recognized by eye around Mikura Island on Feb. 27 as a direct effect, and it was presumed that the amount of rain increased on the mountainous area. It was clearly successful that the artificial cloud echoes were recognized about 1.5 h later after the seeding on Feb. 27 as a chain-type cloud echo at east-northeast of Mikura Island on the composition radar echo of Japan Meteorological Agency as an indirect effect. The echo height reached from 3000 m to 5000 m when the artificial cloud moved to the leeward side of Miyake Island. It was recognized that the seeding rate of liquid carbon dioxide with about 5 g/s is suitable in a little inside convective cloud with an air temperature below -5°C.View full abstractDownload PDF (1418K) -
Kenichi TATSUMI, Tsutao OIZUMI, Yosuke YAMASHIKI2013 Volume 69 Issue 3 Pages 159-172
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSThis study investigates the applicability of the statistical downscaling model (SDSM) in downscaling precipitation in Shikoku region, Japan, for both historical and future time periods. We calibrated the SDSM model using the National Center for Environmental Prediction (NCEP) reanalysis datasets and daily time series of precipitation in Shikoku acquired from nine surface daily observation points (SDP) and validated the NCEP model and general circulation model (GCM) outputs of HadCM3 under SRES A2 and B2 scenarios (1961-2099). To predict the future mean and extreme precipitation, we investigated the approach of downscaling the outputs of a GCM to a local scale using the SDSM to downscale precipitation in present and future climate scenarios. The results showed that in both climate scenarios: (1) the time series generated by SDSM indicates a clear increasing trend in the mean daily precipitation values in future winters and a decreasing trend in the summer; (2) the annual change in the number of days that exceed the 20 mm/day precipitation (R20) would significantly decrease in northern Shikoku; (3) the changes of R100 in the northern region were much more severe than in the southern region under both scenarios because the changes of R100 decreases in the northern region occurred in spring, summer and autumn; and (4) in the future, the stable reservation of water for agricultural use becomes difficult in the northern Shikoku region. Annual maximum precipitation frequency was analyzed by fitting more than 50 continuous and discrete distributions. Distribution-estimated magnitudes of annual maximum precipitation were compared for studied return periods using H3A2 and H3B2 in the base period (1961-1990), 2020s (2011-2040), 2050s (2041-2070), and 2080s (2071-2099). We are confident about the impact of climate change on precipitation, and in the ability to simulate extreme precipitation events that may affect agriculture.View full abstractDownload PDF (1316K) -
Tamon FUMOTO, Toshihiro HASEGAWA, Weiguo CHENG, M. M. HOQUE, Yasuhiro ...2013 Volume 69 Issue 3 Pages 173-190
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSA process-based biogeochemistry model, DNDC-Rice, was modified to simulate rice growth and CH4 emission under elevated atmospheric CO2 concentration, [CO2]. It simulates the effect of [CO2] on the photosynthetic rate by an empirical parameter (β-factor), which is calibrated based on observed biomass under varied [CO2]. Rice growth is linked to CH4 emission through rhizodeposition of C and the rice plant's conductance of CH4, which depend on the root biomass and tiller density, respectively. DNDC-Rice was tested using five years of rice growth data and four years of CH4 emission data from a free-air CO2 enrichment (FACE) experiment in a Japanese rice field, in which [CO2] was controlled at 200 ppm above ambient.
In the experiment, FACE increased the average final aboveground biomass by 11% and seasonal CH4 emission by 22%. By calibrating the β-factor of photosynthesis calculation, DNDC-Rice successfully predicted the final aboveground biomass across the years and the [CO2] treatments. However, it underestimated the enhancement of CH4 emission by FACE, to be only 9% as the average over the four years. We found this discrepancy to be attributed to the modeling of photosynthesis, root growth and exudation, and rice tiller conductance of CH4 under elevated [CO2]. These results indicate that DNDC-Rice needs to be further refined using detailed data on these plant processes in order to simulate future CH4 emission under elevated [CO2].View full abstractDownload PDF (1053K)
Short Paper
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Shohei KONNO, Tomoko NAKANO, Hideo TAKAHASHI2013 Volume 69 Issue 3 Pages 191-200
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSWe investigated the temporal and spatial variability of nighttime temperatures in a complex of small valleys in the western Kanto Plain, Saitama Prefecture, Japan, by conducting horizontal and vertical temperature measurements throughout one winter season. The magnitude of nocturnal cooling in the valley was greater in March than during the mid-winter period. The horizontal distribution of mean nighttime temperatures and nocturnal cooling under clear and calm conditions indicated that temperatures in the middle or lower areas of the valleys tended to be lower than those in the upper areas even though the elevation differences were small. Vertical profiles of air temperature measured by a kytoon system on clear nights revealed the development of a temperature inversion above the valley floor at night; the top of the inversion exceeded the height of the ridge adjacent to the valley. Under these conditions, down-valley flows of cold air were a significant phenomenon below the inversion layer. Our results suggest that local nocturnal drainage flow below the temperature inversion could contribute to nocturnal cooling in these valleys.View full abstractDownload PDF (1154K) -
Daitaro ISHIKAWA, Shinya FUKUDA, Shigenori ARIMITSU, Kazuhiko OHBA, Yu ...2013 Volume 69 Issue 3 Pages 201-207
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSThis study describes a method for evaluating the change in the water content of leaves by using visible and near infrared spectral analyses. The spectral behaviors within the 400-1100 nm region that corresponded to drought in the sample leaves were investigated using a spectrometer. Bands in the 470-490, 600-620, and 650-690 nm regions that are due to chlorophyll absorption were identified. Importantly, these bands were blueshifted by about 6-9 nm and showed decreased intensities. In particular, the band in the 650-690 nm region correlated to the water content with a coefficient of determination (R2) of 0.74. The spectral patterns of the loadings, which were calculated by principal component analysis (PCA), appeared similar to those of the second derivative spectra. Furthermore, the score of the first principal component obtained by PCA was clearly separated at the water content value of 48.1%. Therefore, the results provide a chemical understanding of band behavior in the 400-1100 nm region and suggest that PCA may support the evaluation of water content and stress in leaves by using this spectral region.View full abstractDownload PDF (863K) -
Masumi OKADA, Hirofumi NAKAMURA, Han-Yong KIM, Mayumi YOSHIMOTO2013 Volume 69 Issue 3 Pages 209-214
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSWe introduce a high-precision microlysimeter suitable for measuring the water balance of paddy rice (Oryza sativa L.). The microlysimeter was designed to measure the changes in water level in a rice paddy using a laser displacement sensor as a gauge. The system consists of a plant and soil container paired with a PVC service cylinder. The container and cylinder are connected by a flexible tube that maintains the water surface at the same level in both parts of the system. The container is placed in a rice paddy, where it is exposed to wind and rain; therefore its water surface level fluctuates widely. To reduce the influence of this undesirable fluctuation, the laser gauge was mounted in the service cylinder, which was enclosed by a weather shelter. This system successfully minimized the influence of water surface fluctuations and enabled the measurement of water losses or gains at hourly intervals with an error of 0.1 mm or less. The microlysimeter allowed accurate measurements of evapotranspiration and is sensitive enough it could potentially detect sap flow taken up by the rice plants at night.View full abstractDownload PDF (670K)
Research Notes
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Hideki UEYAMA2013 Volume 69 Issue 3 Pages 215-227
Published: March 10, 2013
Released on J-STAGE: September 25, 2013
JOURNAL FREE ACCESSSince air temperature maps are essential tools in various fields, there are several studies to estimate surface air temperature at unobserved locations. Air temperature maps have also practical use in a variety of agricultural fields. Practical methods for estimation of surface air temperature are currently not physical but statistical methods. Recent studies on air temperature map development using statistical methods are classified according to method type: (1) rasterizing point data using general techniques for interpolation within computer software such as geographic information systems, i.e., “general rasterization methods”; (2) considering geographical functions based on several factors, i.e., “geographical function methods”; and (3) interpolating anomalies between observation data and long-term normals, i.e., “anomaly methods.” Geographical function or anomaly methods should be more suitable when interpolating current conditions. It is difficult, however, to select a single method, because the most suitable method depends on the area. Practical types of spatial resolution for agriculture are suggested, i.e., high resolution less a few hundred meters, herein called “precise data,” and low resolution greater than that scale, called “coarse data.” Substantial data at specific sites are required for efficient management toward productivity improvement, but current resolutions in agriculture are primarily coarse data. A verified estimation method for surface air temperature, combining statistical and physical techniques, is described as one for acquiring practical and precise data. The method continuously estimates temperature from existing observation data using a new meteorological scale, a radiative cooling scale (RCS). RCS values were calculated using numerical weather prediction model outputs to estimate daily values. Daily temperature at six sites was estimated to have a root-mean-square error of 0.47 K and a mean error of -0.02 K, validating the values for complex terrain such as hilly areas.View full abstractDownload PDF (976K)
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