| Co-Investigator(Kenkyū-buntansha) |
SASAKI Choichi Hirosaki University, Faculty of Agriculture and Life Science, professor, 農学生命科学部, 教授 (30162374)
TOKUNAGA Koichi Iwate University, Faculty of Agriculture, professor emeritus, 農学部, 名誉教授
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2000: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
This study does the investigation of the durability of pore system formed by roots in which the above-mentioned research is unsolved with the purpose. "X-ray stereography of soil pore" which TOKUNAGAs created clarified that "pore system formed by roots" which derives from the plant root excels as soil coarse pore. In the conventional research, TOKUNAGAs clarified the durability 32000 in the Towada volcanic ash soil in the loess in China indigo plant rice pad in 16000. Then, this study succeeded for the search in respect of sedimentation cross section which was old 720000 ago in Iwate volcanic ash soil. The sample made connected soil sampling to be direction of depth in it, and continuity, durability, plant opal as a facies-fossil of pore system formed by roots were examined. Nishine district (in pine, swamp shrine and Egarinai 3 layer 13 〜 72 year:) and Iwate Kawaguchi district the research method where soil profile is located in known Mt. Iwatesan north It is older than (12 layer and
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72000 years ago: Iwate Kawaguchi (it is four-layered) and volcanic ash soil of ball mountain ma (7 layers, temple forest (a layer)) were made to be an object. Soil sampling did the lower layer division in the age independence from the surface part where the layer that it is lamina profunda and is old existed. Pore images imaged the sample of the 4.2cm cube by X-ray and solid contrast radiography using contrast media (CH_2I_2). The durability of pore system formed by roots was shown in the degradation class (0: Soundness 1 : Slightness 2 : Inside-3 : Severity 4 : Disappearance) of pore. The outline of the result is shown in the following. The physical condition of the each trial soil texture was distributed from coarse sandy loam within the light clay, and dry density was high, and hydraulic conductivity was small, and it was the minute soil as volcanic ash. Pore images required in X-ray stereo-radiography was the distribution in which pore system formed by roots of the Nishine district was slight from the soundness. Surface part soil in the Iwate Kawaguchi was sound, when clear pore system formed by roots is shown, and when it is shown in the degradation class. Tamayama soil in the lower layer division intermingled to the severity in which the as degradation was close to the disappearance from the little slightness. Pore system formed by roots was not most shown Terabayashi soil in the lower layer division. The continuity of pore system formed by roots in the about 1m unit, there was the fluctuation, and there was the fluctuation over soil layer 1m soil layer small. And, the validity as a facies-fossil-ness was in the identification of the type of pore system formed by roots on the plant silicic acid. Though pore system formed by roots there was the continuity in the soil layer 720000 year ago of the prophase pleistocene series, when the above be summarized, and pore images was disappearing concerning the permeability in the part lower layer, there was the durability in the whole layer, and it also had the significance as a facies-fossil-ness. Less
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