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No.40 (1993/12) >

Title :西表島,竹富町上原の丘陵地における黄色土の土壌特性(生産環境学科)
Title alternative :The soil properties of yellow soil profiles on the hillside at Uehara, Taketomi-cho, Iriomote Island (Department of Enviromental Sciences and Technology)
Authors :渡嘉敷, 義浩
志茂, 守孝
Authors alternative :Tokashiki, Yoshihiro
Shimo, Moritaka
Issue Date :1-Dec-1993
Abstract :アグロフォレストリーの考えを含めた土地利用に資する目的で,西表島,竹富町上原の丘陵地に分布する,アカメガシワ,ウラジロアカメガシワ,オオバギ,ハルランイヌビワ等の樹種が優占する各黄色土壌について,土壌断面の特徴やその化学性について調べた。土壌断面では,A,B,C層の各厚さは土壌断面間で異なったが,B_2層の厚さは27∿28cmの範囲でほぼ近似し,B層位の土色は黄色土層の特徴を示した。そして,表層土では土壌侵食を受け易いことが推察された。土地利用面では,土壌侵食防止の対策が必要であることが示唆された。化学性では,自然肥沃度は著しく低いことが認められた。すなわち,ほとんどの土層で,pH(H_2O)は明酸性,EC値は0.05mS/cm前後,CEC値は4me/100g前後,交換性のCa含量は2.2me/100g以下,Mg含量は0.8me/100g以下,KおよびNa含量はいずれも0.1me/100g前後,塩基飽和度は約27%前後,全窒素含量は0.1%未満,可給態リン酸含量は1.0mg/100g以下,有機態炭素含量は1.0%以下,腐植含量は2%以下をそれぞれ示した。土地利用面では,塩基類の補給や有機物の多施用の対策が必要であることが示唆された。
It was investigated with the aim utilizing soils of grove, wood and/or forest including an idea of an agroforestry system. The purpose of this research was to find the fundamental data of the properties in profiles and chemistry of yellow soils which were distributed on the hillside at Uehara, Taketomi-cho, Iriomote Island. Three profiles were selected on the soils with dominated by one or two kinds of tree : Mallotus japonicus Muell. Arg., Mallotus paniculatus (Lam.) Muell., Macaranga tanarius Muell. Arg. and Ficus benguetensis Merr.. Each thickness of the A, B and C horizon was different among three soil profiles, nevertheless, B_2 horizon was almost similar in thickness from 27 to 28cm. Based on the color of B horizon, these soils could be included in yellow soil. It was suggested that their surface soils have a high potential erosion. It seems reasonable to suppose that it is necessary a good preparation of land use to protect the soils from erosion. It was recognized that almost soils were remarkably low in natural soil fertility. These are the following chemical data obtained through almost soil horizons : about 5.2 in pH (H_2O); about 0.05mS/cm in EC; about 4me/100g in CEC; less than 2.2 and 0.8me/100g in exchangeable Ca and Mg, respectively; about 0.1me/100g in each exchangeable K and Na; about 27% in base saturation; less than 0.1% in total N; less than 1.0mg/100g in available P_2O_5; less than 1.0% and 2% in organic carbon and organic matter, respectively. According to all of these properties is obvious that it is necessary to consider the rate of fertilizer application of plant nutritions and organic matter as amendment from the viewpoint of land use.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/3795
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.40 p.99 -106
Appears in Collections:No.40 (1993/12)

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