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No.21 (1974/12) >

Title :人工降雨によるマージ土壌の侵食試験(沖縄における農地保全の基礎的研究 V)(農業工学科)
Title alternative :Experimental study on erosion of MAJI soil by simulated rainfall (Fundermental studies on fanmland Conservation in Okinawa V.) (Department of Agricultural Engeneering)
Authors :翁長, 謙良
Authors alternative :Onaga, Kenryo
Issue Date :1-Dec-1974
Abstract :以上の結果を要約すると次のようになる。1.人工降雨の雨滴径の分布については0.5mm以下の細滴以外は略々似せることができるが1.5mm以上の雨滴は終速度に達していない。2.従って個々の雨滴のエネルギーの点で自然降の雨滴との差はあるが, 雨滴全体のエネルギーで促えるとそれを補うことができる。3.極めて高い強度の降雨についてKとSの流去水は殆んど同じだが, 流出土量はKの方がはるかに大きい。4.Sは耐水性団粒の含量がKより大きくそのことが流出土量の大小に影響していると考えられる。5.総流出土量は概して降雨強度(降雨量)の増加とともに増大することが認められた。最後にこの実験は文部省科学研究費による研究の一部であることを附記する。
A study on soil erosion was made by means of simulated rainfall. Two different types of soil were used as the test soil. They were called KUNIGAMI MAJI soil, SHIMAJIRI MAJI soil respectively. The test soil grading was as follows. [table] The test soil box was 80cm length, 42cm wide, 25cm depth was set with a slope of 10 degrees. The simulated rainfall was dropped frome a place 3.30 meters high above the surfaec of test soil. Drop-size distribution of both natural rainfall and simulated rainfall are shown in Fig. 1. The results of this experiment are shown as follows. 1 Drop-size distribution of artificial rainfall was allmost simulated with those of natural rainfall except under drop-sizo of 0.5mm by diameter. 2 Although the terminal velocity of each drop is not equivalent to those of natural rainfall, the total energy of artificial rainfall can be equalized to those of natural rainfall by strengthen the intensity of rainfall. 3 Runoff of both test soil is almost the same in case of very high intensity raimfall, but soil loss of KUNIGAMI MAJI soil is larger than that of SHIMAJIRI MAJI soil. 4 Aggrigating degree, which is considerd one of the important index of erosion resistance of soil, of SIMAJIRI MAJI soil is larger than that of KUNIGAMI MAJI soil. And this will influenced to the soil loss quantity of both test soil. 5. If the intensity of the rainfall increase the amount of the test soil become larger.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/4374
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.21 p.181 -188
Appears in Collections:No.21 (1974/12)

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