比抵抗探査法と水の安定同位体比を用いた温暖湿潤気候におけるトウモロコシの吸水深度に関する研究  [in Japanese] The depth of water uptake by maize root system estimated by 2-D resistivity monitoring and water stable isotope under the warm humid climate  [in Japanese]

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Abstract

生育に伴う蒸散量の変化が大きいトウモロコシ(Zea maize L.)を対象として,各生育ステージにおける吸水深度の特徴と,栽植密度が吸水深度に与える影響の検討を行った。土壌水分量の鉛直2次元断面の観測を行うことができる比抵抗探査と,吸水深度の推定に土壌水分量を必要としないアプローチである土壌水と茎の水の安定同位体比を用いて吸水深度の把握を行った。<BR> 吸水深度は蒸散活動と密接な関係をもっており,蒸散活動が最も盛んな開花期では土壌乾燥に伴う吸水深度の深部への移行が早くなった。また,開花期においては密植区と疎植区ともに土壌面蒸発よりも蒸散の割合が大きかったが,密植区は蒸散量が疎植区よりも多いため土壌乾燥が早く進行した。このため,密植区のトウモロコシは根を鉛直方向に多く伸長し,より深部の土壌水を利用するようになることが示された。<BR> 葉が枯れるのに伴い蒸散活動が減衰する登熟期では,土壌乾燥に伴う吸水深度の深部への移行が開花期より遅くなった。また,登熟期では,疎植区において土壌面蒸発と蒸散の割合が同程度であったため,開花期と比較して密植区と疎植区の浅層における吸水可能な土壌水分量の差が少なくなっていた。このため,密植区と疎植区における土壌乾燥に伴う吸水深度の深部への移行速度に明確な違いがなくなることが示された。

The characteristics of water uptake depth by root system was studied for both the each growth stage and the influence of planting density of maize (Zea maize L.), which has relatively large transpiration rate change during its growth. Electrical resistivity tomography method was used for monitoring the soil water content distribution along the two-dimensional vertical cross-section and also the stable isotope in the water of stem and soil was measured to estimate the water uptake depth by root system without soil water content. <BR> The estimated water uptake depth showed a close relationship with the transpiration activity. In blooming stage, when the transpiration activity is most active, the transition of water uptake depth to deeper depth with soil drying has developed faster. The maize transpiration rate is higher than soil evaporation rate in a dense and sparse planting area. However, the reduced soil water content has been shown faster in the dense planting area than that in the sparse planting area because of the difference of total transpiration rate. This situation influences the maize root growth distribution and the root grows deeper in the dense planting area than that in the sparse planting area to get soil water from the deeper depth during its blooming stage. <BR> In fully matured stage, when the transpiration activity decreased with leaves dying, the transition of water uptake depth to deeper depth with soil drying has been slower than that in blooming stage. Also the maize transpiration rate is approximately equal to soil evaporation rate in the sparse planting area, thus difference of available soil water amount at the shallow layer was smaller than that of blooming stage between the dense and sparse planting area. Hence, there was no clear difference on transition of water uptake depth to deeper depth with soil drying between the dense and sparse planting area.

Journal

  • Journal of Japanese Association of Hydrological Sciences

    Journal of Japanese Association of Hydrological Sciences 42(4), 147-165, 2012-11-30

    THE JAPANESE ASSOCIATION OF HYDOROLOGICAL SCIENCES

References:  38

Codes

  • NII Article ID (NAID)
    10031138154
  • NII NACSIS-CAT ID (NCID)
    AA11123427
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    13429612
  • NDL Article ID
    024313112
  • NDL Call No.
    Z15-251
  • Data Source
    CJP  NDL  J-STAGE 
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