論文 - 鈴木 伸治
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Impact of Soil Amendments and Alternate Wetting and Drying Irrigation on Growth, Physiology, and Yield of Deeper-Rooted Rice Cultivar Under Internet of Things-Based Soil Moisture Monitoring. 査読あり 国際共著 国際誌
Amin, M. W., Sediqui, N., Azizi, A. H., Joya, K., Amin, M. S., Mahmoodzada, A. B., ... & Mihara, M.
AgriEngineering 7 ( 3 ) 69 - 93 2025年06月
記述言語：英語 掲載種別：研究論文（学術雑誌）
Effective water and soil management is crucial for crop productivity, particularly in rice cultivation, where poor soil quality and water scarcity pose challenges. The response of deeper-rooted rice grown in soils amended with different soil amendments (SAs) to Internet of Things (IoT)-managed alternate wetting and drying (AWD) irrigations remains undetermined. This study explores the effects of various SAs on DRO-1 IR64 rice plants under IoT-based soil moisture monitoring of AWD irrigation. A greenhouse experiment executed at the Tokyo University of Agriculture assessed two water management regimes—continuous flooding (CF) and AWD—alongside six types of SAs: vermicompost and peat moss (S + VC + PM), spirulina powder (S + SPP), gypsum (S + GS), rice husk biochar (S + RHB), zeolite (S + ZL), and soil without amendment (S + WA). Soil water content was continuously monitored at 10 cm depth using TEROS 10 probes, with data logged via a ZL6 device and managed through the ZENTRA Cloud application (METER GROUP Company). Under AWD conditions, VC + PM showed the greatest decline in volumetric water content due to enhanced root development and water uptake. In contrast, SPP and ZL maintained consistent water levels. Organic amendments like VC + PM improved soil properties and grain yield, while AWD with ZL and GS optimized water use. Strong associations exist between root traits, biomass, and grain yield. These findings highlight the benefits of integrating SAs for improved productivity in drought-prone rice systems.
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Water resources survey and model analysis in Dikhill area, Djibouti 査読あり 国際共著
SUZUKI R., SUZUKI S., SAITO S., ADEN D., MALOW Fadoumo A.
Journal of Arid Land Studies 34 ( 3 ) 105 - 110 2024年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：The Japanese Association for Arid Land Studies
<p>The republic of Djibouti is a dry country with an annual maximum temperature and rainfall being 40 degrees Celsius and less than 150 mm, respectively. Geographical coordinates, groundwater depth, and condition of water use were evaluated at 17 sites within a small catchment in Dikhil. Half of the sites were established after the 1990s and unlisted in the database summarized by the government of Djibouti. The other half sites are listed but all of them had an error of geographical coordinates. Groundwater depth was analyzed using a simulation model (GETFLOWS) for the purpose of evaluating the potential of water resources, and the simulated water levels were in proportion to the observed water levels with the root mean square error (RMSE) being 9.4 m.</p>
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Improving Irrigation Water Use Efficiency and Maximizing Vegetable Yields with Drip Irrigation and Poly-Mulching: A Climate-Smart Approach. 査読あり 国際共著
Bwire, D., Watanabe, F., Suzuki, S., & Suzuki, K.
Water 16 ( 23 ) 3458 - 3473 2024年12月
記述言語：英語 掲載種別：研究論文（学術雑誌）
Water management is a significant aspect of sustainable vegetable farming, especially in water-scarce regions. This, in addition to weed infestations, limits vegetable yields, which negatively affect food security in developing regions, particularly East Africa, where livelihoods chiefly depend on rain-fed agriculture. Vegetable farming, especially tomato cultivation, requires more water. By promoting mulching, a soil water conservation tool, we can control surface evaporation (E), which, together with irrigation, enhances effective water use and vegetable yields. The experiments for this study were conducted at the Tokyo University of Agriculture, Japan, to evaluate the influences of different irrigation conditions and poly-mulching on weed control, tomato yields, and water use efficiency. The study was conducted from May to September 2018 on a 30 m2 plot in an open-ended greenhouse using drip irrigation for tomato cultivation. Three predetermined irrigation conditions of 4, 3, and 2 mm/day were applied on black poly-mulched and bare ridges. Data on soil conditions—soil temperature, as well as meteorological variables, including solar radiation and temperature—were measured using thermocouple sensors and micro-hobo weather stations, respectively, during the tomato cultivation, while yield components—growth, yield, water productivity, and sugar content—were determined after harvest. The results of a two-way ANOVA show that irrigation conditions with poly-mulching reduced the weed biomass significantly, and improved yields and water use efficiency compared to the irrigation conditions on bare ridges. The application of 4, 3, and 2 mm/day irrigation with poly-mulching significantly reduced the weed biomass by 5% compared to the same irrigation conditions on bare ridges. Similarly, 4 and 3 mm/day irrigation conditions with poly-mulching significantly increased the tomato yield by 5% compared to 2 mm/day on bare ridges. The bigger roots were concentrated and widely distributed at the shallow soil depth (0–20 cm) of the ridges with high irrigation amounts, while the small and thin roots were in deeper soil layers (30–45 cm). This study provides scientific knowledge on the application of predetermined irrigation conditions that can be (i) integrated into irrigation scheduling and (ii) adopted for regions facing water scarcity and limited or no in situ meteorological data, to improve water use efficiency for vegetable cultivation.
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Estimating irrigation water amounts for tomato cultivation using observed meteorological data in Djibouti
WATANABE Fumio, SUZUKI Shinji, MOHAMED Tabarek Ismael, JITSUNO Masataka, OHSHIMA Hiroyuki, SANADA Atsushi, SHINOHARA Takashi, ABDALLAH Abdillahi Houssein
Journal of Arid Land Studies 32 ( S ) 95 - 99 2022年12月
記述言語：英語 出版者・発行元：The Japanese Association for Arid Land Studies
<p>Irrigation is essential for crop cultivation in arid and semi-arid areas with limited rainfall and water resources. Efficient and effective use of water resources is required and saving irrigation water is important. Djibouti is a very dry region with annual rainfall of about 150 mm and an average annual temperature of 28.6°C. Due to such meteorological conditions, water resources depend mostly on groundwater, and this makes water extremely scarce. Therefore, water saving in agricultural sector is indispensable. This study aims at promoting effective and efficient use of irrigation water in Djibouti. The appropriate irrigation water amounts for tomato cultivation were estimated using CROPWAT provided by FAO and observed meteorological data at Ali Farren farm in Djibouti. The conditions required for calculating the amounts of irrigation water were medium loam soil based on the laboratory results of soil particle size test, and the tomato cultivation period from October to March according to the local farmers. The result showed that the average monthly reference evapotranspiration was 5.7 mm/day annually. Reference Evapotranspiration was maximum in July and August with 8.4 mm/day and minimum in December with 4.6 mm/day. The amount of irrigation water from October to March was about 476 mm which corresponds to the local tomato cultivation period.</p>
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Preliminary study on improvement of soil water retention characteristics by <i>Spirulina</i>.
SUZUKI Shinji, WATANABE Satoru, OMAR Abdillahi Ismail, WATANABE Fumio, SHIMADA Sawahiko
Journal of Arid Land Studies 32 ( S ) 49 - 52 2022年12月
記述言語：英語 出版者・発行元：The Japanese Association for Arid Land Studies
<p>One of the measures to enhance the water use efficiency or to prevent desertification in arid and semi-arid countries is to improve water holding capacity (water retention) of soils. This study focused on<i> Spirulina</i>, a planktonic blue-green unicellular microalgae classified as cyanobacteria. Since the <i>Spirulina</i> inhabits strongly alkaline water body which is generally seen in the tropics, the <i>Spirulina</i> is expected as a locally available soil amendments. Further, the <i>Spirulina</i> secretes Extracellular Polymeric Substances (EPS). The current study assessed the effect of the <i>Spirulina</i> and the EPS powders to improve the soil water holding capacity. Slight addition (0.5 to 5%) of the <i>Spirulina</i> and EPS powders to sandy soils resulted in a significant increase of the readily available water content for crop growth (RAWCC). The effect of the <i>Spirulina</i> on the RAWCC of the sandy soils was similar of that of the bentonite. Meanwhile, soils with textures of Silty Loam and Sandy Loam had little increases in the RAWCCs with those amendments. In addition, the RAWCCs of the soils treated with both <i>Spirulina</i> and EPS powders did not decrease significantly after heat treatment indicating the persistence of the effect. The results of the current study demonstrated the efficiency and its persistence of the <i>Spirulina</i> and the <i>Spirulina</i>-derived EPS to improve soil water holding capacity particularly in sandy soils.</p>
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Meteorological characteristic and evaluation of hedgerow windbreak effect in agricultural lands in Djibouti based on wind dynamics simulation
IRIE Teruaki, SAITO Shuhei, MAY CUEVAS Sergio Azael, SUZUKI Shinji, WATANABE Fumio, SHIMADA Sawahiko, BARKAD Hassan A.
Journal of Arid Land Studies 32 ( S ) 193 - 197 2022年12月
記述言語：英語 出版者・発行元：The Japanese Association for Arid Land Studies
<p>This study aimed to clarify the meteorological characteristics of a farm at Dikhil in Djibouti and to evaluate the windbreak effect of hedgerows to plan and design a pilot farm in Ali Faren based on wind dynamics simulated using observed meteorological parameters. The analysis of meteorological observations at Dikhil farm showed that the east-northeast winds from October to April were twice as strong as the southerly winds from May to September. The computational fluid dynamics (CFD) analysis of the inflow from the east-northeast at a height of 3 m above the ground level confirmed that the windbreak effect of the hedgerows on the leeward side was effective in protecting the vegetable fields. The observations from the Ali Faren pilot farm indicated that the south-southeast prevailing winds blow throughout the year. The CFD analysis of the inflow from the south-southeast at a height of 3 m above the ground confirmed that the windbreak effect of several scenarios of hedgerow planning at the Ali Faren pilot farm was effective.</p>
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A comparative evaluation of lumped and semi-distributed conceptual hydrological models: does model complexity enhance hydrograph prediction? 査読あり 国際共著 国際誌
Okiria, E., Okazawa, H., Noda, K., Kobayashi, Y., Suzuki, S., & Yamazaki, Y.
Hydrology 9 ( 5 ) 89 - 106 2022年05月
記述言語：英語 掲載種別：研究論文（学術雑誌）
The prediction of hydrological phenomena using simpler hydrological models requires less computing power and input data compared to the more complex models. Ordinarily, a more complex, white-box model would be expected to have better predictive capabilities than a simple grey box or black-box model. But complexity may not necessarily translate to better prediction accuracy or might be unfeasible in data scarce areas or when computer power is limited. Therefore, the shift of hydrological science towards the more process-based models needs to be justified. To answer this, the paper compares 2 hydrological models: (a) the simpler tank model; and (b) the more complex TOPMODEL. More precisely, the difference in performance between tank model as a lumped model and the TOPMODEL concept as a semi-distributed model in Atari River catchment, in Eastern Uganda was conducted. The objectives were: (1) To calibrate tank model and TOPMODEL; (2) To validate tank model and TOPMODEL; and (3) To compare the performance of tank model and TOPMODEL. During calibration, both models exhibited equifinality, with many parameter sets equally likely to make acceptable hydrological simulations. In calibration, the tank model and TOPMODEL performances were close in terms of ‘Nash-Sutcliffe efficiency’ and ‘RMSE-observations standard deviation ratio’ indices. However, during the validation period, TOPMODEL performed much better than tank model. Owing to TOPMODEL's better performance during model validation, it was judged to be better suited for making runoff forecasts in Atari River catchment.
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Identifying minimum number of observed rainfall events required for optimal TOPMODEL parameters in mid-sized equatorial catchments 査読あり
Okiria, E., Okazawa, H., Yamazaki, Y., Kobayashi, Y., Suzuki, S.
International Journal of Environmental and Rural Development 10 2020年
記述言語：英語 掲載種別：研究論文（学術雑誌）
水収支モデルであるTOPMODELについて感度解析を行い，重要なパラメーターをいくつかに絞り込んだ。
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近年の降水パターンの変化が農地に及ぼす影響
鈴木 伸治
熱帯農業研究 13 ( 1 ) 37 - 39 2020年
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Applicability of Tank Model in Mid-Sized Catchments in Eastern Uganda
OKIRIA EMMANUEL, OKAZAWA HIROMU, YAMAZAKI YURI, KOBAYASHI YUKIMITSU, SUZUKI SHINJI
International Journal of Environmental and Rural Development 11 ( 2 ) 31 - 37 2020年
記述言語：英語 出版者・発行元：Institute of Environmental Rehabilitation and Conservation, Research Center
<p>Long-term stream discharge data is indispensable in irrigation and drainage design. However, in Uganda, this data is poor and insufficient, limiting irrigation system design. Conversely, the rainfall monitoring network is denser than the river flow monitoring network. Therefore, we attempt to build a model that calculates river discharge from input of rainfall. In this study, the lumped parameter Tank Model was applied. The model was applied to the Namatala River catchment (155 km<sup>2</sup>) in Eastern Uganda. The study sought to ascertain the applicability of a lumped parameter model to a mid-sized catchment. Specifically, the objectives were: 1) To calibrate the numerical values of Tank Model parameters, 2) To verify the Tank Model parameters. This Tank Model required daily rainfall, evapotranspiration and river discharge data during calibration. Data for years 2015 and 2016 was used for calibration and validation respectively. During calibration, Monte Carlo simulation was used to find the numerical values of 16 Tank Model parameters. The best performing calibration parameter set had Nash-Sutcliffe (<i>NS</i>) efficiencies of 0.608 and 0.257 in calibration and validation respectively. However, among the 2015 calibration parameter sets, the one with a calibration <i>NS </i>of 0.502 performed best in validation (<i>NS </i>= 0.526). Equifinality was observed during parameter calibration. By using Tank Model, simulated discharge was divided into its surface runoff, interflow and base flow components. Tank Model was adaptable to Namatala River catchment.</p>
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凍結をともなうオホーツク網走地域の農地における土壌水分の季節変動の特徴 査読あり
鈴木伸治，佐伯ともみ，伊藤博武，渡邉文雄
土壌の物理性 142 5 - 11 2019年07月
担当区分：筆頭著者 記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：土壌部地理学会
オホーツク網走地域の畑圃場において，土壌の凍結と融解，および融雪水の浸透がもたらす水分動態の特徴を明らかにすることを目的に，2011年7月から2012年6月にかけて土壌水分動態の連続観測を行った．最大凍結深は0.28 mであり，表層の土壌水分は，融解直後が1年で最も湿っていた．融雪水の浸透は，非凍結期間の多雨時よりも大きな水フラックスをもたらした．また下層の土壌水分について，土壌の凍結・融解と融雪水の浸透に伴う変化が，非凍結期の無降雨による乾燥とその後の降雨による変化と同等のものであった．さらに，融雪水（116.5 mm）が湛水せずに浸透した．これらのことから，観測された凍結深では，土壌の間隙が多かったことに関連し，透水性の低下が顕著ではなかったことが示唆される．
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Comparison of root distribution pattern between Gramineae and Legume species under various soil and climate condition 査読あり
Suzuki, S., Kobayashi, Y., Watanabe, F., Nakagawa, D., and Izumikawa, T.
28 ( S ) 189 - 192 2018年12月
担当区分：筆頭著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本沙漠学会
イネ科の植物とマメ科の植物の根系の分布の特徴について調査した。作物の種類にかかわらず，また土壌の状態や気候の条件にかかわらず，根の空間的な発達に伴って，根長密度が指数関数的に増加することが明らかになった。また空間的な分布の特性から根長密度を推定する式を提案した。
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Determining the effective Eucalyptus leaves heating temperature that triggers water repellency using medium sand and soil from Kisima area of Samburu, Kenya
Kirui, S. K., Watanabe, F., Suzuki, S., and Souma, R.
28 ( S ) 173 - 176 2018年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本沙漠学会
ケニア国サンブル県でのウォーターハーベスティングを念頭に，炭化したユーカリの葉が土壌の撥水性の向上に及ぼす影響について検討した。
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Verification of availability of GSMaP rainfall data based on the comparison of observed rainfall data in Africa 査読あり
Kobayashi, Y.,Watanabe, F., Suzuki, S., Emmanuel, O., and Kanyike, T.
28 ( S ) 85 - 88 2018年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本沙漠学会
ウガンダ東部において，Global Satellite Mapping of Precipitation (GSMaP)の降雨情報と地上での雨量計による観測データを比較し，GSMaPの特徴や精度について検討した。
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Optimal water use on low pressure drip irrigation system for tomato cultivation in Uganda 査読あり
Denis, B., Watanabe, F., Suzuki, S., and Kuga, S.
28 ( S ) 77 - 80 2018年12月
担当区分：責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本沙漠学会
簡易型で現地でも実施可能な点滴潅漑を利用し，異なる潅水量でトマトの生育を行った。トマトの終了や品質，可能蒸発量と比較することによって，最適な潅水量の算定方法について検討した。
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Estimating optimum irrigation discharge under furrow irrigation in Afghanistan 査読あり
Shams, H. k., Fumio Watanabe, F., Suzuki, S., and Kimura, M.
東京農業大学農学集報 60 ( 4 ) 219 - 224. 2016年03月
記述言語：英語 掲載種別：研究論文（学術雑誌）
アフガニスタンにおける畦間灌漑について，水収支式の積分方程式の解析解をもとに現地の水足試験からインテーク定数を決定し，給水量を適用効率を計算することにより，1 ha のトマト畑全体で1 回の灌漑につき5.1トンの節水が可能であることを明らかにした。
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Soil and hydrological survey for retrieving the characteristics of surface runoff on Kourtimalei reservoir watershed in Djibouti. 査読あり 国際誌
Toyoda, H., Shimada, S., Hirokane, T., Sekiyama, A., Malow, F. A., Hotta, T., Menjo, M., Suzuki, S., and Watanabe, F.
Journal of Arid Land Studies 25 ( 3 ) 241 - 244 2015年12月
記述言語：英語 掲載種別：研究論文（学術雑誌）
ジブチ国クルチマレ流域の流出特性について調査した。
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凍結をともなう網走地域の農地におけるマトリックポテンシャルの季節変動－誘電水ポテンシャルセンサの利用と凍土における浸透ポテンシャルの吟味－ 査読あり
鈴木伸治，葛城拓也，三井ともみ，伊藤博武，岡澤宏
土壌の物理性 126 51 - 62 2014年04月
担当区分：筆頭著者 記述言語：日本語 掲載種別：研究論文（学術雑誌）
冬季に土壌が凍結する網走地域の畑圃場において，マトリックポテンシャルの通年観測を行った。その際，観測に用いた誘電水ポテンシャルセンサの較正や，凍土の不凍水の水ポテンシャルに及ぼす浸透ポテンシャルの影響についての吟味を行った。その結果，圃場では，マトリックポテンシャルの低下（すなわち乾燥）の様子を精度よく明らかにすることができた。
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Estimating pan evaporation in Kabul, Afghanistan. 査読あり
Shams, H. K., Watanabe, F., Suzuki, S., Takahashi, S., and Kashino, M.
23 ( 4 ) 167 - 172 2014年03月
記述言語：英語 掲載種別：研究論文（学術雑誌）
アフガニスタンのカブール市において，気象データからパン蒸発量を推定する方法を提案するとともに，ペンマン法と比較し，実用性について検討した
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ジブチにおけるWorldView-2およびLandsat-8を用いた流域地表面情報収集 招待あり
島田沢彦，ファドモ A マロウ，堀田朋樹，毛受享政，広兼達也，鈴木伸治，渡邉文雄，豊田裕道
沙漠研究 23 ( 4 ) 247 - 250 2014年03月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
ジブチ国の種々の流域において，ウォーターハーべスティング手法によりため池に集水することを目的に，衛星画像データから抽出できる流出解析に資する広域地上面情報の収集手法の開発について検討した。