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System for Evaluating Environmental Factors Which Restrict Water Flow in Soil-Plant-Atmosphere-Continuum

Research Project

Project/Area Number 09356007
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section展開研究
Research Field 生物環境
Research InstitutionIWATE UNIVERSITY

Principal Investigator

HARA Michihiro  Iwate Univ., Dept. Agron. & Forestry, Assoc. Prof., 農学部・農林生産学科, 助教授 (80003763)

Co-Investigator(Kenkyū-buntansha) HONJI Tsuyoshi  Chiba Univ., Labo. Multi. Energy, Assoc. Prof., 園芸学部, 助教授 (60173655)
SHONO Hiroshi  Iwate Univ., Dept. Agron. & Forestry, Research Assoc., 農学部・農林生産学科, 助手 (90235721)
INADA Ikuko  Iwate Univ., Dept. Agron. & Forestry, Assoc. Prof., 農学部・農林生産学科, 助教授 (90110650)
OKUYA Akiko  Yokogawa Denki Co., Ltd., Researcher, 環境システム営業本部, 研究員
Project Period (FY) 1997 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥31,000,000 (Direct Cost: ¥31,000,000)
Fiscal Year 1999: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1998: ¥10,500,000 (Direct Cost: ¥10,500,000)
Fiscal Year 1997: ¥16,900,000 (Direct Cost: ¥16,900,000)
KeywordsSoil / Plant / Atmosphere / SPAC / Transpiration / photosynthesis / Diffusion resistance / Soil water tension / キャピラリーバリア / 水分供給能力 / スペクトル測定 / 画像処理 / 水流 / 水分特性測定法 / 同化速度
Research Abstract

Under the present research project, the following results and knowledge have been obtained and acquired.
1. Simultaneous measurements of transpiration and carbon-dioxide assimilation rates of tomato plants have been conducted with an apparatus for observing water flow in soil-plant-atmosphere-continuum (SPAC) . Results showed both the rates decreased remarkably according to the soil-water tension increase, while the ratio of the two rates remained constant. Daytime courses of vapor diffusion resistance between leaves and atmosphere showed J-shape increases, although the high resistance recovered lower during nighttime. It was concluded that soil-water tension larger than 400 cmHィイD22ィエD20 could be a restriction factor to water flow, however, increase of soil temperature from 15 to 25 ℃ remedied the restriction.
2. Characteristics of the rate of water absorption through root systems versus pressure have been tested. The results indicated that about 7 bar would be required for absorbing amount of water which was lost through the transpiration with the maximal rate, 740 mg/min.
3. Soil-moisture regimes (SMR) , which maintained soil moisture greater than 50% of container capacity (CC) , didn' t give serious stress to potted tomato, whereas those, which allowed soil moisture to decrease to less than 25% of CC, resulted remarkable yield loss.
4 . A theory has been developed to analyze relationships between water volumes and time observed with the so-called one-step outflow method. The new formula have been adopted to obtain water diffusivity of tested soils and justified.
5. Observations of salt affected soils have concluded that rhizomes of salt tolerant plants brought about increase in water permeability of soil, thus finally lead the improvement of salt leaching out of crop soil.
6 . In order to improve the leaching rates with placing coarser materials underneath the crop soil it was effective to make the boundary of two materials inclined.

Report

(4 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • 1997 Annual Research Report
  • Research Products

    (4 results)

All Other

All Publications (4 results)

  • [Publications] Hara M.,Saha R.R.: "Effect of different soil moisture regimes on growth, water use, and nitrogen nutrition of potted omato seedlings"Jpn.J.Trop.Agr.. 44. 1-11 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Hara, M., Saha, R.R..: "Effect of different soil moisture regimes on growth, water use, and nitrogen nutrition of potted tomato seedlings."Jpn. J. Trop. Agr.. 44-1. 1-11 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Hara,M.,Saha,R.R.: "Effect of different soil moisture regimes on growth,water use,and nitrogen nutrition of potted tomato seedlings"Jpn.J.Trop.Agr.. 44・1(印刷中). (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] Saha,R.R.,Hara,M: "Influence of different soil moisture regimes on biomass production,water use,and nitrogen nutrition of tomato plants." Environ.Control in Biol.36・1. 1-12 (1998)

    • Related Report
      1998 Annual Research Report

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Published: 1997-04-01   Modified: 2016-04-21  

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