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• 畑地帯における浮遊土砂および栄養塩流出防止対策の評価に関する研究

  2008.03

Published Papers 【 display / non-display 】

Published Papers 【 display / non-display 】

• Evaluating the Effectiveness of the Biodegradable Superabsorbent Polymer (Fasal Amrit) on Soil Hydrological Properties: A Laboratory Rainfall Simulation Study

  Ruwanpathirana P. P., Sakai Kazuhito, Nakandakari Tamotsu, Yuge Kozue

  Agronomy ( MDPI )  14 ( 11 ) 1 - 22   2024.10 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

  　View Summary

  Superabsorbent polymers (SAPs) are effective soil amendments that can control soil erosion by improving soil quality. However, many commercial SAPs face challenges including limited biodegradability, high costs, and adverse effects on soil hydrological properties, which can lead to increased water and soil loss. This study examined the potential of lower dosages of biodegradable SAPs to improve the hydrological properties of “Shimajiri-maji” (clay) soil. Three concentrations of biodegradable Fasal Amrit polymer (EFP) (P1: 0, P2: 3 g m⁻², and P3: 6 g m⁻²) were evaluated under three simulated rainfall intensities (I1: 35; I2: 70 and I3: 110 mm h⁻¹) and two gradients (7.5%, and 15%) during consecutive storms. The time to generate runoff, infiltration, runoff, soil loss, and water storage (WS) were quantified over one hour. The results show that runoff generation was delayed in EFP-treated soils compared to the control. Both polymer treatments enhanced infiltration (P2 > P3 > P1) and reduced runoff and soil loss (P2 < P3 < P1). Higher EFP rates improved water storage at surface depths (P3 > P2 > P1). EFP-treated soils exhibited lower interrill erodibility, suggesting greater resistance to soil erosion compared to the control. EFP treatments also significantly improved the soil’s physical properties (bulk density, porosity, organic matter, aggregate stability). EFPs can diminish runoff and soil loss as the EFP-treated plots exhibited greater aggregate stability than the control. It was concluded that low EFP concentrations can improve soil hydrological properties and mitigate soil erosion. Further investigations are needed to optimize the EFP concentrations for different soil types.

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    CiNii Research

• A Low-Cost NDIR-Based N₂O Gas Detection Device for Agricultural Soils: Assembly, Calibration Model Validation, and Laboratory Testing

  Bandara, KMTS; Sakai, K; Nakandakari, T; Yuge, K

  SENSORS ( Sensors (Switzerland) )  21 ( 4 ) 1 - 16   2021.02 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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    DOI
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• Agricultural Infrastructure Improvement and Rural Development in Okinawa Islands

  SETOUCHI Hideki, NAKANDAKARI Tamotsu

  Water,Land and Environmental Engineering ( The Japanese Society of Irrigation Drainage and Rural Engineering )  88 ( 7 ) 555 - 560,a1   2020

  Type of publication: Research paper (scientific journal)

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• Pedotransfer functions to estimate hydraulic properties of tropical Sri Lankan soils

  Gunarathna M.

  Soil and Tillage Research ( Soil and Tillage Research )  190   109 - 119   2019.07

  Type of publication: Research paper (scientific journal)

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    DOI

• Sensitivity analysis of plant- And cultivar-specific parameters of APSIM-SUGAr model: Variation between climates and management conditions

  Gunarathna M.

  Agronomy ( Agronomy )  9 ( 5 )   2019.05

  Type of publication: Research paper (scientific journal)

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Presentations 【 display / non-display 】

Presentations 【 display / non-display 】

• N2O emissions from a sugarcane field for spring planting in Okinawa

  Bellido Jose, Sakai Kazuhito, Nakamura S, Kazuro M, Okamoto Ken, Nakandakari T

  第22回日本雨水資源化システム学会研究発表会  (福井市)  2014.11  -  2014.11 

• Analysis of Sediment Yield under Different Sugarcane Cultivation Systems in Urajigawa Watershed Area in Kume Island, Okinawa

  W. H. A. Shantha, Kensuke Okada, Kazuhito Sakai, Tamotsu Nakandakari

  2012 JSIDRE Annual Conference  (札幌市)  2012.09  -  2012.09 

• Identification of Factors Affecting Sugarcane Farmers' Decision on Adoption of Soil Conservation Measures in Okinawa

  W. H. A. Shantha, Kazuhito Sakai, Anshun Yoshinaga, Tamotsu Nakandakari

  2010 JSIDRE Annual Conference  (神戸市)  2010.08  -  2010.09 

• The Effects of Sedimentation Tank to Prevent Suspended Soil Runoff

  Tamotsu Nakandakari, Anshun Yoshinaga, Kazuhito Sakai, Kazutoshi Osawa

  2006 ASABE Annual International Meeting  2006.07  -  2006.07 

Academic Awards 【 display / non-display 】

Academic Awards 【 display / non-display 】

• JRCSA Young Scientists Award

  2013.11   Japan Rainwater Catchment Systems Association  

  　View Summary

  Suspended Soil and Nutrients Trap in Sedimentation Tanks Constructed for Preserving Water Environment in Okinawa

Grant-in-Aid for Scientific Research 【 display / non-display 】

Grant-in-Aid for Scientific Research 【 display / non-display 】

• Grant-in-Aid for Scientific Research(C)

  Project Year: 2023.04  -  2026.03 

• Grant-in-Aid for Scientific Research(C)

  Project Year: 2019.04  -  2023.03 

• Grant-in-Aid for Young Scientists(B)

  Project Year: 2011  -  2013 

  Direct: 3,500,000 (YEN)  Overheads: 1,050,000 (YEN)  Total: 4,550,000 (YEN)

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Social Activity 【 display / non-display 】

• 2025.02

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  2026.03

• 2024.12

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  2025.03

• 2024.11

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  2026.11

• 2024.08

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  2025.03

• 2023.09

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  2024.03

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