Japan Agricultural Research Quarterly: JARQ
Online ISSN : 2185-8896
Print ISSN : 0021-3551
ISSN-L : 0021-3551
最新号
選択された号の論文の11件中1~11を表示しています
REVIEW
Social Science
  • Makoto HIMI
    原稿種別: review-article
    2021 年 55 巻 1 号 p. 1-4
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    This paper derives the issues of further research on the farm-type TMR center (i.e., regional farming system) through a literature review. I categorized studies on the farm-type TMR center into the following three types: (1) the farm-type TMR center system, (2) its management, and (3) its impact on members. I organized the trends of those studies by type, further clarified the issues of each type, and presented other research topics by comparing the farm-type TMR center with the similar notion of community-based farming (CBF). The results were as follows: First, researchers did not necessarily have a common understanding of the farm-type TMR center system. Thus, a unified view was necessary. Secondly, funding and labor problems are two management issues of the farm-type TMR center. In particular, the labor problem issues entail a serious situation. Thirdly, early studies showed a positive impact of the farm-type TMR center on its members, whereas recent studies have shown a negative impact. Finally, a comparison with the CBF study showed that the organizational base of the “local group type” of farm-type TMR center was similar to that of CBF, and that the “local group type” could possibly become an entity of community development.

ARTICLES
Crop Science
  • Tsutomu KANNO, Hisatomi HARADA, Koichi AMAHA, Yoshiyuki ABE, Noritoshi ...
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 5-16
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    Whole-crop silage corn and Italian ryegrass were cultivated during summer and winter in fields contaminated by radionuclide fallout caused by the Fukushima Daiichi Nuclear Power Plant accident, with three different tillage treatments: shallow tillage treatment (tilled with a rotary tiller to a depth of about 10 cm), conventional tillage treatment (plowed with a normal moldboard plow to a depth of about 20 cm and harrowed with a rotary tiller to a depth of about 15 cm), and deep tillage treatment (plowed with a moldboard plow to a depth of about 35 cm and harrowed with a rotary tiller to a depth of about 15 cm). Vertical distribution of radioactive cesium (Cs) in the soil layers of 0 cm-10 cm, 10 cm-20 cm, and 20 cm-30 cm, and concentrations of radioactive Cs in forage samples were compared among the tillage treatments, as well as the soil chemical properties of those soil layers.

    Radioactive Cs in the soil surface layer (0 cm-10 cm) moved into the deeper layers at 10 cm-20 cm and 20 cm-30 cm due to plowing in the conventional and deep tillage treatments. However, significant differences were not observed for both species, either in the radioactive Cs concentration in forage samples or the radioactive Cs transfer factor from soil to plants among the tillage treatments. Moreover, the radioactive Cs concentrations in those plants and their TFs were relatively low for both species. These results suggest that radioactive Cs transfer was reduced by mixing the surface soil, even in the shallow tillage treatment. Furthermore, the exchangeable K2O content of soil was higher than 0.32 g/kg DW in all soil layers of the experimental fields, and such high content of exchangeable K2O in the soil was apparently another major reason why radioactive Cs uptake by both species was significantly restricted in all tillage treatments.

Agricultural Environment
  • Tabito MAEDA, Soh SUGIHARA, Tomohiro NISHIGAKI, Naoko MIYAMARU, Koichi ...
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 17-27
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    The objective of this study was to evaluate N2O emissions during the first three months after different nitrogen (N) source treatments involving green manure and chemical fertilizer in a sugarcane field in Okinawa, Japan. Four treatment plots were established: 100 and 300 kg N ha−1 chemical fertilizer (100N and 300N plots, respectively); green manure (Crotalaria juncea, 150 kg N ha−1, C:N=20; GM plot); and the control (0N plot). We regularly measured N2O flux and soil inorganic N (NH4+-N and NO₃-N), and also recorded environmental data. There were no significant differences in the fluctuation pattern and peaks of N2O emissions between the 100N and GM plots, and total N2O emissions were comparable, though the applied N amount was higher in the GM plot. Little rainfall in the early period should limit microbial activity in the 100N plot, though soil NH4+-N and NO₃-N contents were higher in the 100N plot than in the GM plot. Total N2O emissions in the 300N plot were 1.5-times higher than in the 100N and GM plots. Collectively, the results suggest that the amount of applied N more strongly affected N2O emission than the difference in N substrate quality.

  • Yasuhiro TOMITAKA
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 29-33
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    A simple detection method using a rapid immunofilter paper assay was developed in this study. First, the N protein gene-coding region of a chrysanthemum stem necrosis orthotospovirus (CSNV) isolate collected in Japan was amplified by reverse transcription-polymerase chain reaction and introduced into the multi-cloning site of the pMAL-c5X vector. The vector was introduced into Escherichia coli (Rosetta DE3) competent cells, and ca. 75 kDa fusion protein of CSNV-N and maltose binding protein was obtained by liquid culture. Antiserum was obtained from rabbits immunized with the fusion protein. IgG was purified from the antiserum, and its titer was determined by enzyme-linked immunosorbent assay to be approximately 200-fold. Immunochromatograms were prepared by rapid immunofilter paper assay using the IgG. CSNV was detected in diseased plants using the immunochromatograms and red polystyrene particles at a concentration of 8%.

Agricultural Engineering
  • Akira IZUMI, Toshikazu HORI
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 35-43
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    A tank cascade system consisting of several small earth dams has been developed for the irrigation system in Sri Lanka. The frequent flooding in recent years has led to the collapse of small earth dams or their spillways (Oka et al. 2013). Such collapse poses a danger to people living downstream.Therefore, disaster prevention measures including water management must be improved to prevent overflow of the embankments and the flooding of populated areas. Small earth dams and spillways frequently collapse in Japan as well. Systems have been developed for monitoring and predicting water levels in reservoirs to reduce the damage from flooding. This paper introduces the water level monitoring system and water level estimation system in tank cascades in Sri Lanka to improve disaster prevention measures. We successfully monitored the water level of small earth dams from a remote location, and the water level estimation system in Sri Lanka was used to calculate the water level of small earth dams.

  • Nobuaki KIMURA, Ikuo YOSHINAGA, Kenji SEKIJIMA, Issaku AZECHI, Hirohid ...
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 45-58
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    Drainage management in a complicated system in an agricultural lowland must operate pumps flexibly and quickly, based on the water level at the pumping station. A data-driven model without any physical-based information was implemented in a complicated drainage management system to predict the water level of a lagoon near a main drainage pumping station. We employed a long shortterm memory (LSTM) model as an advanced neural network model to utilize the field datasets obtained from water-related facilities and sensors over about eight years as model input data. We performed sensitivity tests for model accuracy with different types of data and locations of data using cross-validation with an error quantity between observed and predicted water levels at the main drainage pumping station. The results showed that the LSTM model with the input of all available datasets predicted better than the models using several parts of datasets or it was roughly equivalent to those for water levels over the entire observed period in 3-h and 6-h lead times. In addition, the LSTM with only inputs of the water level and rainfall observed by drainage pumping stations performed better for the observed subperiod, including the severest flood event.

Social Science
  • Yuki ISHIKAWA-ISHIWATA, Jun FURUYA
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 59-67
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    Soybean rust (SBR) is a damaging disease that has threatened soybean production worldwide. In Brazil, the world’s top soybean exporting country, SBR-resistant cultivars have been developed to prevent severe soybean production losses. To evaluate SBR effects on soybean production in Brazil and on the global soybean market, we developed soybean supply and demand models for Brazil, the U.S., Argentina, China, the EU-28, and the rest of the world based on functions that include yield, area, exports, imports, stock changes, demands, and price linkages. Three scenarios were set: no production loss caused by SBR, severe production loss caused by ineffective fungicides, and the adoption of SBR-resistant cultivars. To evaluate the effects of SBR and SBR-resistant cultivars on soybean production and the global soybean market, our simulation results suggest that the world price of soybeans would increase due to severely damaged soybean production. The adoption of resistant cultivars can alleviate losses in soybean production and reduce costs for fungicide application. Therefore, adopting SBR-resistant cultivars in soybean production is necessary to maintain a stable global supply of soybeans.

Animal Science
  • Ken ASAI, Khin Ohnmar LWIN, Abraham G. TANDANG, Rosalina M. LAPITAN, J ...
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 69-75
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    The objective of this study was to compare the differences in ruminal fermentation and the proportion of rumen bacteria between swamp buffalo and cattle in the Philippines. Six crossbred swamp buffalo and six crossbred cattle used in the study were fed the same diet for 16 weeks. Rumen fluid was collected at weeks 0, 8, and 16 of the fattening period. Diversity of the rumen bacteria was analyzed using 454 pyrosequencing. The population density of major cellulolytic bacteria was determined by real-time PCR. Animal performance was not significantly different between buffalo and cattle. The concentration of total short chain fatty acids was found to be higher in the buffalo than in the cattle; however, the proportions of each short chain fatty acid were not significantly different. The proportion of Bacteroidetes increased in buffalo during the sampling period, whereas it was constant in cattle. In contrast, the proportion of Firmicutes and Fibrobacteres decreased in both groups of animals throughout the experiment. Although the density of cellulolytic bacteria between the two groups of animals was not found to be significantly different, the proportion of cellulolytic bacteria decreased during the fattening period. Both animal species exhibited similar traits for composition and population change of bacteria during the fattening period, suggesting that the microbial community structure might be dependent on feed rather than animal species.

  • Naoko MORIYA, Naoko YAMAGISHI, Tatsuhiko GOTO, Hikari OTABI, Hiromi NI ...
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 77-83
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    Stress contributes to mental disorders as well as functional gastrointestinal disorders. In functional gastrointestinal disorders, gastrointestinal motility is thought to play a role. Therefore, we evaluated the effects of chronic social defeat stress on gastrointestinal motility in C57BL/6J mice, by measuring gastric emptying, fecal pellet output, and gastrointestinal transit. In mice subjected to 10 days of social defeat stress, serum corticosterone concentrations were significantly higher, relative tissue weights of spleen and adrenal gland tissues were significantly heavier, and thymus sizes were smaller than in the control mice. Stressed mice exhibited social avoidance behavior in a social interaction test and anxiety-like behavior and lower locomotor activity in an elevated plus maze test. In gastric emptying test, stressed mice displayed increased gastric emptying rate with significant suppression of short-time (30 min.) test diet intake. Fecal pellet output and gastrointestinal transit were not different in control and stressed mice. These results suggest that chronic social defeat stress influences gastric motility. Thus, the social defeat stress model may be useful for studying psychiatric disease and functional gastrointestinal disorders simultaneously.

Fisheries
  • Naoaki TEZUKA, Yoshitake TAKADA, Toshihiro SHIGETA, Motoharu UCHIDA
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 85-96
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    Predation is considered a significant factor contributing to the recently observed low survival rates of asari clam (Ruditapes philippinarum) in Japan. Longheaded eagle ray, blackhead seabream, portunid crabs, predatory gastropods, and ducks are suggested as potential predators; however, the relative significance of these predators has yet to be evaluated. In this study, we conducted 31 single-day time-lapse camera observation trials during summer at 28 stations within 12 habitats of the asari clam in Japan (ranging from temperate to subarctic regions) to determine the relative abundance of predators in each habitat. And in a trial at the Nakatsu tidal flat in southwestern Japan, where a previous study observed a low survival rate of the asari clam, the absolute abundances of different predator taxa were estimated by quantifying the underwater visibility and visible area in images. The blackhead seabream (Acanthopagrus schlegelii), a known temperate subtropical species, was identified as the most frequently observed predator. A. schlegelii was widely observed in 8 of the 12 habitats in the southwestern to central regions of Japan. The longheaded eagle ray was not observed, and portunid crabs and predatory gastropods were few in this study. At Nakatsu, a maximum of 39 individuals of A. schlegelii were observed in a single trial (via single-day images captured every 2 min.), indicating the significance of this predator relative to asari clam mortality at this site. A. schlegelii appeared on the tidal flat during high tide, and its hourly mean abundance exceeded 20 ind./100 m2 during high tide after dawn. Rising seawater temperatures along Japan’s coast might increase the predation risk for asari clam posed by temperate-to-subtropical risk species.

  • Yukio MATSUMOTO, Tomoki MAEDA
    原稿種別: research-article
    2021 年 55 巻 1 号 p. 97-106
    発行日: 2021/01/01
    公開日: 2021/02/26
    ジャーナル フリー

    Hatcheries in Japan’s Tohoku region induce the gonadal maturation of Haliotis discus hannai by controlling the water temperature. However, the cost of heating the water places financial pressure on the hatcheries. This study showed that the heating cost in rearing abalone broodstock can be reduced using a simple closed recirculating system that was constructed using common commercial products.During our experiment, the water quality parameters including ammonia-, nitrite- and nitratenitrogen were kept under recommended safety levels. pH did not show a significant decrease during the breeding period. Although the calcium ion concentration and salinity value were less stable in the closed recirculating system than in the flow-through system, both were within adequate levels for rearing abalone over long periods. Moreover, the gonadal maturation of H. discus hannai was not inhibited by rearing in a closed recirculation system. And the electric power consumption in the closed recirculating system was reduced to about one-seventh of that in the flow-through system.

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