巻号一覧
71 巻 (2015)
- 4 号 p. 245-
- 3 号 p. 161-
- 2 号 p. 55-
- 1 号 p. 1-
71 巻, 4 号
選択された号の論文の9件中1～9を表示しています
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Full Paper
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Taichi MAKI, Osamu MORITA, Koji NISHIYAMA, Yoshinori SUZUKI, Kenji WAK ...2015 年 71 巻 4 号 p. 245-255
発行日: 2015年
公開日: 2015/12/10
ジャーナル フリーAn artificial rainfall experiment was conducted using an aircraft to seed liquid carbon dioxide (LCD) under particular weather and topographic conditions near the northern area of Saijo, Ehime, with the climatic type of the Inland Sea of Japan on Dec. 27, 2013. Following the seeding, a convective cloud developed quickly above Saijo between 11:30 and 11:50, and rain fell within a short time. A high cumulus cloud was dissipated by the rain, and the cloud over a mountainous area had rapidly and almost completely disappeared by around 12:30, approximately one hour after seeding. The rain at 5 mm/h was observed for 5-6 minutes at around 11:50 at the Saijo City office area, and 0.5 mm of rain was observed up until 13:00 at the Saijo Fire Station. This rainfall was believed to be artificial, and it was significant in the southern mountainous area of Niihama and could be clearly observed visually throughout the area from the aircraft at around 12:10. The artificial rainfall was expected to be observed at amounts of 0.5 mm and 4.0 mm at Ohjoin and Besshiyama of Niihama Fire Station, respectively, and at 0.5 mm during the period from 11:50-12:00 at AMeDAS Tomisato located south of Shikokuchuo. Rainfalls of 0.5 mm from 14:20-14:30 at AMeDAS Ikeda, 2.0 mm from 13:30-15:00 at AMeDAS Kyojo, and 1.0 mm from 13:00-15:00 in the areas of Miyoshi, Tokushima, and Ohtoyo, Kochi, were thought to be artificial considering the seeding time, seeding position, wind direction, and wind speed. The main line of the rainfall area was Saijo-Besshiyama-Kyojo, and the effect of the artificial rainfall expanded up to 70 km of the lee side. The amount of rain was estimated at roughly 1.3 million tons in the areas of Saijo, Ikeda, Sugeo, and Kurotakigawa. Thus, the artificial rainfall experiment conducted through the seeding of LCD at Saijo was clearly successful.抄録全体を表示PDF形式でダウンロード (12934K) -
Yodai OKUYAMA, Kiyoshi OZAWA, Michiko TAKAGAKI2015 年 71 巻 4 号 p. 256-262
発行日: 2015年
公開日: 2015/12/10
[早期公開] 公開日: 2015/09/19ジャーナル フリーIn order to increase the efficiency of nutrient utilization in solution culture systems, it is indispensable to understand how plants absorb nutrients. A series of experiments were conducted using hydroponic culture system in the first to third experiments and soil culture system in the fourth experiment in a greenhouse in Okinawa, Japan. In the first experiment, changes in NO3-N absorption were measured every three hours during a 24-hour period on 40 days after transplanting (DAT) in cucumber. In the second experiment, daytime and nighttime NO3-N absorption were measured from 45 to 48 DAT in five crops including cucumber. In the third experiment, NO3-N, NH4-N, and K absorption in daytime, nighttime and shaded conditions were determined from 30 to 34 DAT in bitter gourd, a substitute crop for cucumber, and water spinach. In the fourth experiment, daytime and nighttime (NH4)2SO4-15N absorption rates were measured from 9 to 12 DAT in cucumber. The results showed that daily NO3-N absorption in cucumber peaked twice, just before midday and again just after the nightfall. The corresponding fluctuation pattern was observed in all other tested crops, with 20-41% of the total absorption occurring at night. Absorption rate of 15N in cucumber cultivated in soil also increased in daytime and decreased at night, with the nighttime rate accounting for 39-40% of the daily total absorption. The average nighttime NO3-N, NH4-N, and K absorption percentages of the daily total before shading the plant were 34-35%, 49-51%, and 33-49%, respectively. During the shaded period, these nutrient absorption rates dramatically decreased, except for NH4-N which was not affected by shading. Across all experiments, 20-51% of total absorption took place at night, the majority of which may concentrate around the early nighttime. Furthermore, the absorption rates may be influenced by photosynthetic products.抄録全体を表示PDF形式でダウンロード (3204K) -
Mioko ATAKA, Yuji KOMINAMI, Mayuko JOMURA, Kenichi YOSHIMURA, Takatumi ...2015 年 71 巻 4 号 p. 263-270
発行日: 2015年
公開日: 2015/12/10
ジャーナル フリーWe evaluated the temporal changes in the vertical distribution of leaf litter respiration (RLL) due to changes of leaf litter water content (WLL) within the leaf litter layer (L layer) using in situ direct measurements. To investigate the vertical distribution of RLL and WLL within the leaf litter layer over a time-series, we measured the RLL and WLL of 10 separate layers in vertical leaf litter stacks fixed to the forest floor using wire pins. Measurements were conducted for 30 stacks in a temperate broad-leaved secondary forest between May 2008 and January 2009. In the warm season, high RLL was observed at high WLL, while low RLL was observed at low WLL. RLL was comparatively lower during the cool season than during the warm season regardless of the magnitude of WLL. The temperature sensitivity of RLL differed depending on WLL; temperature increases under low-moisture conditions had small effects on RLL, while under higher-moisture conditions, RLL was more responsive to temperature increases. Small differences in position within the leaf litter stack affected the vertical variation of WLL and, consequently, there was large distribution in RLL during the wet period and small distribution in RLL (totally small values) during the dry period. Thus, CO2 efflux from the net L layer was strongly affected by RLL distribution induced by the local wetting within the L layer. In estimating CO2 efflux from the L layer using water content of the L layer, monitoring of the water content of the L layer, which takes into account the vertical distribution in WLL within the L layer, is necessary.抄録全体を表示PDF形式でダウンロード (4282K)
Short Paper
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Tomoki MOCHIZUKI, Tasuku SAITO, Gou HIRAI, Makoto MIWA, Tetsushi YONEK ...2015 年 71 巻 4 号 p. 271-275
発行日: 2015年
公開日: 2015/12/10
ジャーナル フリーTo measure monoterpene emissions from plants grown in widely used open-top chambers (OTCs), we developed a gas sampling method that does not involve the stimulation of leaves and branches. Four clones of Japanese cedar (Cryptomeria japonica) were grown in the OTC (60 × 60 × 120 cm). To sample the monoterpenes, the existing OTC was used for a dynamic enclosure system. The open side (top) of the OTC was covered using a transparent acrylic plate with a hole (10 cm in diameter) in the center. Purified air was supplied through 50 holes (3 mm in diameter) made in a ring-shaped Teflon tube horizontally fixed near the bottom of the OTC. Monoterpene emission rates measured during the afternoon (n = 8-10) were well correlated with temperature (r2 = 0.94 - 1.00), and the total monoterpene emission rate during a certain period of the experiment can be estimated using this relationship and recorded temperature. Our results suggest that the developed gas sampling system using the existing OTC is a reliable method to collect monoterpenes emitted from plants without stimulating leaves and branches. It can be used to compare the monoterpene emission potential of plants affected by environmental stresses applied for OTC experiments.抄録全体を表示PDF形式でダウンロード (1880K) -
Seiji SHIMODA, Tomotsugu YAZAKI, Zenta NISHIO, Takahiro HAMASAKI, Tomo ...2015 年 71 巻 4 号 p. 276-281
発行日: 2015年
公開日: 2015/12/10
ジャーナル フリーThe appropriate control of soil frost depth could potentially balance wheat production and kill unharvested potato tubers. We examined possible soil frost control by snow compaction on winter wheat, without reducing wheat productivity. The target soil frost depth was more than 0.3 m, because our previous studies indicated the complete kill of unharvested potato tubers at such depths. The target frost depth was achieved by two snow compaction events following the development of a decision-making system by our research group to accomplish appropriate frost depth for the frost-kill of unharvested potato tubers. The yield components of winter wheat were not significantly different between the designed and control (no compaction) practices. Frequent compaction significantly reduced grain yield by causing a decline in shoot dry weight and the number of spikelets. Our results indicate that soil frost depth control may contribute toward balancing both wheat yield and the frost-kill of unharvested potato tubers.抄録全体を表示PDF形式でダウンロード (2198K) -
Atsushi MARUYAMA, Takahiro HAMASAKI, Ryoji SAMESHIMA, Manabu NEMOTO, H ...2015 年 71 巻 4 号 p. 282-291
発行日: 2015年
公開日: 2015/12/10
ジャーナル フリーThe timing of panicle emergence in rice (Oryza sativa L.) is an important trait. We studied the effects of increasing temperatures during growing seasons on the emergence of first panicle, consequent emerging panicle numbers, and grain yields in rice plant using temperature gradient chambers (TGCs) located in a part of Japan with a humid subtropical climate. Four japonica varieties, Koshihikari, Akitakomachi, Hitomebore, and Nipponbare, were exposed to different temperatures in the TGCs. The number of days from transplanting to heading (DTH) differed among temperatures. Increasing temperatures both accelerated and delayed the timing of heading. Extreme temperatures (>40°C daily maximum) increased the DTH, whereas moderately high temperatures decreased or did not change the DTH. Increasing temperatures after heading affected the number of panicles emerging. The final panicle number increased with temperature in Koshihikari and Akitakomachi. In these varieties, spikelet fertility and mean grain weight of early-emerging panicles were lower at higher temperatures because of the occurrence of grain sterility. However, the grain numbers and grain weights of late-emerging panicles were greater under higher temperatures, and total grain yields were not significantly different among the temperature treatments. We concluded that late-emerging panicles recouped the yield of rice plants, compensating for grain sterility.抄録全体を表示PDF形式でダウンロード (860K)
Research Notes
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Hideki UEYAMA, Masanobu KATO, Hajime KAWAMUKAI, Masaru IKEGAMI, Hiroyu ...2015 年 71 巻 4 号 p. 292-301
発行日: 2015年
公開日: 2015/12/10
[早期公開] 公開日: 2015/09/17ジャーナル フリーDegradation of the quality of Yamadanishiki sake rice has become more evident in the last 15 years, which is partly attributable to high temperature damage to the rice during heading. In response, an information system has been developed to determine the suitable planting period for this rice variety. A key input to this system is daily mean air temperature data at fine spatial resolution, and here an estimation method to calculate such data on a 50-m grid is presented. This database contains daily mean air temperature for 244 days in target regions from April through November over 15 years (1996-2010). The database is obtained by applying a method whose essence is to convert air temperature to potential temperature and build estimation models of the potential temperature difference between an estimation site and existing observation site. The potential temperature differences are partitioned into two components: a “standard site component (Tssc)” and “estimation site component (Tesc).” Estimation models for Tssc and Tesc are developed using a radiative cooling scale, i.e., the difference of potential temperature between an upper level and ground level. Daily air temperature at each output grid was estimated to have a root mean square error of 0.5°C. Our method is able to acquire precise daily air temperature for past, present and future at the existing observation site, without newly costs for installation and maintenance of regular observing instruments.抄録全体を表示PDF形式でダウンロード (2482K)
Special Collection: Sensing and Monitoring Research Group, SAMJ
Full Paper
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Yoshiyuki TAKAHASHI, Nobuko SAIGUSA, Ryuichi HIRATA, Reiko IDE, Yasumi ...2015 年 71 巻 4 号 p. 302-317
発行日: 2015年
公開日: 2015/12/10
[早期公開] 公開日: 2015/09/16ジャーナル フリーWe report the four-year (2006-2009) measurements of the net ecosystem CO2 exchange flux (NEE) over a deciduous needle-leaf plantation forest in the foothills of Japan's highest mountain, Mt. Fuji. We focus on the characteristics of temporal variations in NEE and their relationships to environmental factors and phenology in a forest stand. We evaluate year-to-year variations in the seasonal patterns of flux components and investigate factors controlling the NEE. During the growing season, light availability is likely to affect the photosynthetic uptake of CO2 at the site. We found significant differences in the length of the growing season for the four years; these are due mainly to variations in the timing of the progress of the autumnal coloring of leaves. The timing for the start of the autumnal coloring of leaves is highly dependent on when the daily lowest air temperature drops below 10°C. Secondly, we investigate the characteristics of short-term and long-term variations in the structure of CO2 storage in the forest stand using a newly developed profiling system. We demonstrate the characteristics of temporal variations in the vertical distribution of CO2.抄録全体を表示PDF形式でダウンロード (10671K)
Research Notes
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Keisuke ONO, Atsushi MARUYAMA2015 年 71 巻 4 号 p. 318-329
発行日: 2015年
公開日: 2015/12/10
[早期公開] 公開日: 2015/09/12ジャーナル フリーIncreasingly, agriculture and related industries rely on real-time measurements of surface fluxes and device control based on flux measurements. We have developed a program that computes the eddy-covariance fluxes of CO2 and H2O in real-time on a commercial data logger model. The calculated flux values are targeted for device control. The performance of the program was compared with those of published software programs on maize field data. The calculated fluxes were consistent among the programs. Because practical onsite and real-time quality control procedures of flux measurements were unavailable, we developed a quality control procedure for our program that utilizes sensor disability signals. Filtering the sensor-disabled signals greatly improved the detection of anomalous fluxes during rainy periods. However, filtering the instationary fluxes by the standard deviation criterion was of limited practical use. By slightly modifying the source code, we can adapt the framework of our program to other combinations of sonic anemometer and gas analyzer.抄録全体を表示PDF形式でダウンロード (5653K)
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