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Katsutoshi Seki

    Department of Accounting and Finance　Professor
Last Updated :2025/06/06

Researcher Information

Degree

  • Ph.D.（1998/03 The University of Tokyo）

URL

Research funding number

  • 40313069

ORCID ID

Researcher ID

  • R-7809-2018

J-Global ID

Profile

  • My research focuses on physical processes in the unsaturated (vadose) zone, in the basic theory of flow and application of the theory to environmental problems. Hydraulic parameters are important for the modeling of water flow in soil, and I made a simple web interface, SWRC Fit, for determining the parameters from laboratory experiment. I also made unsatfit and other programs of soil physics, and also some recreational programs, and publish them at GitHub.

    I am also interested in biological processes in soil associated with physical properties. I have numbers of publications in the topic of bioclogging, and these publications are frequently cited.

    I have a broad interest in environmental topics. At Toyo University, I am teaching an introductory course of "Environmental Science" to attract interest to environmental problems for students of various field of major. I published several papers related to environmental problems in soil. The topics include alkalinization of soil, contamination of soil by fallout radiocesium and strontium, physical and chemical properties of soil affected by forest fire, and remediation of soil with biobarrier technique.

Research Interests

  • bioclogging   Vadose zone   放射性物質   Soil hydrology   Soil physics   Hydraulic conductivity   微生物   クロッギング   モデル   目詰まり   土壌微生物   メタン   炭素循環   透水性   半乾燥地   間隙構造   団粒   水質汚濁   物質循環   Soil   Environment   

Research Areas

  • Environmental science/Agricultural science / Environmental agriculture
  • Environmental science/Agricultural science / Rural environmental engineering and planning
  • Environmental science/Agricultural science / Environmental dynamics

Academic & Professional Experience

  • 2015/04 - Today  Toyo UniversityFaculty of Business AdministrationProfessor
  • 2008/04 - 2015/03  Toyo UniversityFaculty of Business AdministrationAssociate Professor
  • 2013/04 - 2014/03  University of Strasbourg (France)Laboratory of Hydrology and GeochemistryInvited Professor
  • 2007/04 - 2008/03  The University of TokyoGraduate School of Agricultural and Life SciencesAssistant Professor
  • 1998/12 - 2007/03  The University of TokyoGraduate School of Agricultural and Life SciencesResearch Associate
  • 2002/08 - 2003/05  Cornell University (USA)Department of Crop and Soil SciencesVisiting Scholar
  • 1998/04 - 1998/11  The University of TokyoResearcher

Education

  • 1995/04 - 1998/03  The University of Tokyo  Graduate School of Agricultural and Life Sciences
  • 1993/04 - 1995/03  The University of Tokyo  Graduate School of Agricultural and Life Sciences
  • 1991/04 - 1993/03  The University of Tokyo  Faculty of Agriculture  農業工学科（卒業）
  • 1989/04 - 1991/03  The University of Tokyo  College of Arts and Sciences  理科一類
  • 1986/04 - 1989/03  Tokyo Gakugei University Senior High School
  • 1983/04 - 1986/03  Tsukimino Junior High School

Association Memberships

  • Society of Environmental Science, Japan   The Japanese Geotechnical Society   Japanese Society of Soil Physics   The Japanese Society of Irrigation, Drainage and Rural Engineering   

Published Papers

Books etc

Conference Activities & Talks

Works

  • Katsutoshi Seki Software 2024/06 
    This app was created with Flutter. Puzzles were created with Python program which is also published.
  • Katsutoshi Seki Software 2024/05
  • Katsutoshi Seki Web service 2023/01
  • Katsutoshi Seki Software 2022/01
  • SEKI Katsutoshi Web service
  • SEKI Katsutoshi Web service 
    The soil hydraulic parameters for analyzing water movement in variably saturated soil can be determined by fittig soil hydraulic model to a soil water retention curve. SWRC Fit performs nonlinear fitting of 5 soil hydraulic models to measured soil water retention curve. Web interface is available. Initial estimate of parameters is automatically determined by the program. Five models are (1) Brooks and Corey model, (2) van Genuchten model, (3) Kosugi model, (4) Durner model and (5) Seki model. This software is primarily intended for scientists in the field of hydrology and geoscience to help their research. It may also be used for educational purposes.
  • 関 勝寿 Others Wikipedia 
    英語版 Wikipedia では土壌物理学に関するしっかりとした記事が書かれているが、日本語版 Wikipedia の記事はあまりにも貧弱であるため、記事を翻訳している。翻訳した記事の一覧はURL参照。

MISC

Industrial Property Rights

Awards & Honors

  • 2024/10 Japanese Society of Soil Physics JSSP Award (Paper Award)
     団粒構造が発達した土壌の水分特性曲線の回帰手法の改良— dual-van Genuchten モデルのパラメータ決定の自動化に向けた取り組み— japan_society 
    受賞者: K. Seki;Y. Iwata;Y. YanaiI;K. Kameyama
  • 2018/07 Elsevier Outstanding reviewer award (Geoderma)
     
    受賞者: Seki, K.
  • 2006/08 Japanese Society of Irrigation, Drainage and Reclamation Engineering Research Promoting Award
     微生物が土壌の透水性に及ぼす影響に関する一連の研究 
    受賞者: Seki, K.選考経過：本業績は、土壌微生物が土壌の透水性に与える影響などを実験的に研究し、微生物ばかりでなく菌類も因子であること、微生物活性の温度依存性、微生物起源のガスの影響など、多くの成果を得たものであり、学術的に高く評価できると考えられ、研究奨励賞に値すると判断した。

Research Grants & Projects

  • 毛乌素沙地包气带土壤水分运移规律与地下水补给机制（毛烏素砂地における不飽和帯の土壌水分移動特性と地下水涵養メカニズム）
    中国自然科学基金委員会：
    Date (from‐to) : 2024/01 -2027/12 
    Author : 王力
  • Ecohydrological separation processes and mechanism in a sub-humid Loess Area
    National Natural Science Foundation of China：
    Date (from‐to) : 2022/01 -2025/12 
    Author : 王力
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2022/04 -2025/03 
    Author : 岩田 幸良; 関 勝寿
  • 農林生産環境中における放射性核種の濃度変動の要因と動態の解明
    農林水産省：令和3〜6年度放射能調査研究委託事業
    Date (from‐to) : 2021/04 -2024/03
  • 中小企業診断士養成コースの中小企業向け教材開発について
    東洋大学：特別研究（教育システム開発共同研究）
    Date (from‐to) : 2011 -2013 
    Author : 研究代表者: 小嶌正稔
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2008 -2011 
    Author : MIYAZAKI Tsuyoshi; NISHIMURA Taku; IMOTO Hiromi; MIZOGUCHI Masaru; SIKI Katsutoshi
     
    The purpose of this research was to make clear transport phenomena of materials through vadose zones, which are still vague mainly because of the lack of knowledge in missing sinks and missing sources of them. We succeeded in obtaining new findings :(1) salt accumulations due to fluctuations of relatively shallow groundwater levels,(2) excess CO_2 emission from soils to the atmosphere due to infiltration of rain water,(3) irregular CO_2 emission from soils to the atmosphere due to the priming effects after application of organic matters,(4) unique accumulation of carbon inside the soils under forest fire events, and(5) missing sources and missing sinks in vadose zones under possible climate changes.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2007 -2009 
    Author : EGUCHI Sadao; YAMAGUCHI Noriko; FUJIWARA Hideshi; MORI Yasushi; SEKI Katsutoshi
     
    A novel method for estimating the travel time and origin of the mobile colloid particles in soil was developed by using the environmental radioisotopes of ^7Be, ^<137>Cs and ^<210>Pb strongly adsorbing to the soil colloids for tracing the mobile colloid particles. Based on this method, the colloid particles discharged from the tile drainage in a clayey soil and that moving downward through the subsoil of a sandy soil were found to be mainly originated from the surface soils ; furthermore, the travel time of the colloid particles transported through the clayey soil was calculated to be approximately 35d.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2005 -2007 
    Author : MIYAZAKI Tsuyoshi; NISHIMURA Taku; MIZOGUCHI Masaru; SEKI Katsutoshi; FUJIKAWA Tomonori
     
    The homeostatic function of soils is defined as the tendency of stable equilibrium in physical, chemical and biological conditions of soils. If the homeostatic function of soils is reduced, the natural environment may be damaged more by the global climate change and by the anthropogenic disturbance of environment On the other hand, if the homeostatic function of soils is induced, the natural environment may be more stable and sustainable. The purpose of this study was to find the environmental preservation strategy by optimizing the homeostatic functions of soils. The results of this study are summarized into three categories. 1. Homeostatic function of soils on water cycles Through the elaborate investigation of the relation between the salt accumulation on the land surface and the fluctuation of shallow ground water level in north-east part of China, we discovered that some few mm supply of water into the clayey soils lifted up the shallow ground water level up to 30cm or 100cm, which resulted in inducing the evaporation rate from the soil surface and in the salt accumulation. We concluded that the acceleration of evapo-transpiration rate by planting the salt patient grasses may induce the homeostatic function of soils. 2. Homeostatic function of soils on carbon cycles It is well known that the CO_2 gas emission from soils increases quickly when rain water infiltrate into soils. We found that this sudden increase of CO_2 emission is attributed to the sudden increase of microbiological activities with the increase of soil moisture. The priming effect of soils, which describes the excess emission of CO_2 compared with supplied organic matter into the soils, was observed experimentally and was discussed in detail. 3. Homeostatic function of soils on thermal cycles High temperatures of soils under forest fires, especially in tropical forest, damage the biological environment We investigated the homeostatic functions of soils under the forest fire where the soil moisture reduced the increase of soil temperature by absorbing the latent heat of water vaporization.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2001 -2004 
    Author : MIYAZAKI Tsuyoshi; MIZOGUCHI Masaru; SEKI Katsutoshi; FUJIKAWA Tomonori; NISHIMURA Taku
     
    The transport phenomena of mass and energy in deep soils, where the direct effects of climate changes and human activities on the ground surface hardly reach in a short time, have serious influence on both local and global natural environments. Researches on this issue, however, have been poorly improved, because the transport phenomena in deep soils have been dealt with in the border area among such fields as groundwater engineering, geology, soil mechanics, soil science, hydrology, and agricultural engineering. This study aimed to clarify the transport phenomena of mass and energy in deep soils by using both experimental and field studies. Five outcomes of this study are emphasized as follows : 1.Gas Phases, such as CO2 and CH4, in deep zones of a wet land were detected both in a field and in a soil column. The importance of gas discharge by the outburst rather than by the molecular diffusion was dearly verified. 2.Zero flux plane (ZEP) of soil water were detected through both experiments and simulations for the first time. The abrupt disappearance of the downward-shifting ZFP and subsequent upward soil water flow from deep soil zone was reported for the first time in this study. 3.Rain water percolation in deep soil zone was analyzed to evaluate the excess water holding capacity in the vadose zone to design the buried water container underground. The modified formula from Guelf permeameter method was effectively applied. 4.Mixing of grass fragment generated from waste and byproducts into soils were effective to maintain the high water permeability of intensively compacted soils in such a field like high school ground. 5.A bio-venting technique was applied to re mediate contaminated deep zone soils by oil-like materials. The difference of the contact areas of microbes and ventilated air in soils affected to the remediation efficiency.
  • 文部科学省：科学研究費補助金(奨励研究(A), 若手研究(B))
    Date (from‐to) : 2001 -2002 
    Author : 関 勝寿
     
    微生物の土粒子上における局所的偏在効果により、クロッギング現象に透水性の異方性が発現することを、昨年度は5cm角の立方体カラムおよび暑さ1cmの直方体カラムを用いたカラム実験により検証した。その実験結果を元に、異方性のモデルを作成した。1つ目のモデルは、カラム全体に均質かつ異方的に透水係数の低下が起こるという1層モデルである。この異方性は微生物の局所的偏在効果によって説明される。実験結果の詳細な分析により、このモデルでは完全に説明ができないことが示された。2つ目のモデルは、クロッギングの起きた層と起きなかった層の2層が形成されるという2層モデルであり、3つ目のモデルは、クロッギングが著しく起きた層と、わずかに起きた層、起きなかった層の3層が形成されるという3層モデルである。いずれのモデルでも実験結果を説明することはできた。このことは、透水性の異方性には、微視的な局所的偏在効果だけではなく、層の形成による巨視的な異方性があることを示している。後者の巨視的な異方性については、従来クロッギングの層厚が数ミリメートルと大変薄く、層厚と透水係数を実測することが困難であることが問題視されている。2層モデルおよび3層モデルでも、この点がネックであった。そこで、4つ目のモデルとして、クロッギング係数(クロッギング層内の透水係数/クロッギング層厚)を定義した。クロッギング係数を用いることで、層厚および透水係数を測定することなく、クロッギングの程度を示すことができ、クロッギングの起きた土壌の透水性を記述することができる。すなわち、鉛直一次元流れにおける薄層クロッギング現象について、統一的な記述をすることができるようになった。この理論を、たとえばクロッギングが問題視されている揚水井のような円筒座標系といった、異種の流れの場にいかに適用していくかを、今後の課題とする。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 1998 -2000 
    Author : MIYAZAKI Tsuyoshi; SEKI Katsutoshi; MIZOGUCHI Masaru
     
    This research aims at developing a technique to control water permeability of soils to required values by multiplying the microbe in soil or making it decrease. In a model experiment, hydraulic conductivity changes of the glass beads of different diameters were measured. Hydraulic conductivity at the upper layer decreased more rapidly for smaller particle diameter beads, because the nutrient was mainly consumed at the upper layer resulting in less nutrient at the lower layer. In on-site measurement at Bibai peatland in Hokkaido District, methane gas produced by bacteria is accumulated in the ground. To simulate this methane producing process, a laboratory column experiment was conducted. When the groundwater level was lowered by 10cm, the redox potential at the 5cm depth decreased to less than -150mV at 6 day after the start of percolation. As a result, a lot of methane emission into the atmosphere was observed. Based on the result of the above experiment and on-site measurement a mathematical model explaining the hydraulic conductivity decrease by microbial activity was built. The difference in particle diameter influences microbial growth rate and a colony formation phenomenon was expalined by this model.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 1997 -1999 
    Author : MIYAZAKI Tsuyoshi; MIZOGUCHI Masaru; NAKANO Masashi; NISHIMURA Taku; SEKI Katsutoshi
     
    The purpose of this study were to (1) find the causes why soils are undergoing serious degradation recently in the 380 ha upland fields in Fukaya, Saitama Prefecture, (2) classify the effects of soil degradation on the migration of such environmental materials as water, solutes (including salts, nitrogen, phosphorous, etc.), and gasses (including OィイD22ィエD2,COィイD22ィエD2, NィイD22ィエD2O etc.), and (3) propose the ways of soil restoration by which physical properties and drainage efficiency of the soils are recovered. The main results are as follows. 1. The suffering from deterioration of drainage efficiency and excess water in upland fields were due to not only by soil degradation but also configurations of structures such as roads, drainage canals, green houses etc. 2. The saturated hydraulic conductivities of soil samples from well drained fields were not necessary higher than those from poorly drained fields. This contradiction was explained by other physical properties of soils. 3. The poor efficiency of drainage from upland fields were attributed to the low stability of aggregation, high sensitivity to the application of salts, the tendency of easy-to-form surface crusts, and high consistencies. 4. The soil degradation was classified into two types : one is the surface soil degradation where the soils are mechanically disturbed, directly compacted and periodically fertilized, and other is the subsurface soils degradation where the soils are indirectly compacted resulting in the increase of bulk density. 5. The deep plowing was effective for the restoration of subsurface soils but plowing with organic matter did not show any advantage for the physical properties of soils. 6. Application of polyacrylamid (PAM) may be effective for the soil restoration especially in its permeability. Further investigation of the PAM efficiency is needed.

Teaching Experience

  • Programming with Python
    Toyo University
  • Mathematics in Finance
    Toyo University
  • Environmental Science
    Toyo University
  • Computer Workshop
    Toyo University

Committee Membership

  • 2019/10 -2023/03   Geosciences   Editorial board

Others

  • 2019/12 -2025/03 東洋大学 将棋研究会 顧問
  • 2010/06 Passed Applied Information Technology Engineer Examination, Information-technology Promotion Agency (IPA)
  • 2009/02 環境社会検定試験 合格
  • 2004/01 TOEIC Listening & Reading 公開テスト 930点取得

Other link

researchmap