Effects of water absorption by tree roots on spatial variation in surface soil water conditions on a forested hill slope

• Project/Area Number: 26850096
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Forest science
• Research Institution: The University of Tokyo
• Principal Investigator: Oda Tomoki 東京大学, 大学院農学生命科学研究科(農学部), 特任助教 (70724855)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000); Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2015: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2014: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
• Keywords: 土壌水分 / 森林斜面 / 硝酸態窒素 / 吸水深度 / 地表面蒸発 / 森林土壌 / 微生物量 / 飽和・不飽和浸透 / 蒸発散 / 微生物動態 / 同位体

Outline of Final Research Achievements

This study evaluated the effects of water uptake by trees on spatial variation in surface soil water content on a forested hill slope. Soil water content, canopy interception, ground evaporation, physical properties of soil and fine root volume in the surface layer were measured in upper and lower hill slope plots, and the effects of water uptake were estimated using model simulations. Spatial variation in soil water content was mainly explained by spatial patterns of physical characteristics of the soil. The effects of water uptake depth of trees and evaporation were weaker.

Research Products

• [Presentation] 森林斜面における表層土壌の水分環境形成メカニズムの解明 (2017)
  • Author(s): 藤目直也・小田智基・酒井佑一
  • Organizer: 第128回日本森林学会大会
  • Place of Presentation: 鹿児島大学（鹿児島県鹿児島市）
  • Year and Date: 2017-03-26
• [Presentation] カラム土壌を用いた降雨中の浸透流出及び水質形成の実験的検討 (2017)
  • Author(s): 酒井佑一・小田智基
  • Organizer: 第128回日本森林学会大会
  • Place of Presentation: 鹿児島大学（鹿児島県鹿児島市）
  • Year and Date: 2017-03-26
• [Presentation] Spatial pattern of the throughfall volume on a steep slope dominated by deciduous broad-leaved trees (2015)
  • Author(s): Tomoki Oda, Marino Hiraoka, Kazuki Nanko, Norifumi Hotta, Nobuhito Ohte, Masakazu Suzuki, Yoshimi Uchiyama
  • Organizer: American Geophysical Union Fall Meeting 2015
  • Place of Presentation: San Francisco, USA
  • Year and Date: 2015-12-15
  • Int'l Joint Research
• [Presentation] スギ・ヒノキ林内での斜面に沿った土壌中の無機化・硝化および含水率の空間的変動 (2015)
  • Author(s): 加藤宏有 ・ 大手信人・ 小田智基 ・ 磯部一夫 ・ 浦川梨恵子
  • Organizer: 第126回日本森林学会大会
  • Place of Presentation: 札幌
  • Year and Date: 2015-03-27 – 2015-03-28
• [Presentation] Long-term changes of water and chemical budgets after clear-cutting of a small headwater catchment in Japan (2014)
  • Author(s): Tomoki Oda, Tomohiro Egusa, Nobuhito Ohte, Manami Takeda, Masakazu Suzuki
  • Organizer: American Geophysical Union Fall Meeting 2014
  • Place of Presentation: San Francisco, USA
  • Year and Date: 2014-12-15 – 2014-12-19