沖縄県のサトウキビ畑土壌における可給態ケイ酸の定量評価とその規定要因の解析  [in Japanese] Evaluation of available silicate content and its determining factors in the soils of sugarcane fields in Okinawa, Japan  [in Japanese]

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Author(s)

    • 矢内 純太 Yanai Junta
    • 京都府立大学大学院生命環境科学研究科 Graduate School of Life and Environmental Sciences, Kyoto Prefectural University
    • 宮丸 直子 Miyamaru Naoko
    • 沖縄県農業研究センター|東京農工大学大学院生物システム応用科学府 Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology|Okinawa Prefectural Agricultural Research Center
    • 中尾 淳 Nakao Atsushi
    • 京都府立大学大学院生命環境科学研究科 Graduate School of Life and Environmental Sciences, Kyoto Prefectural University

Abstract

<p>沖縄県で基幹作物として栽培されているサトウキビは,イネ科植物の有用元素であるケイ素(Si)の適切な管理による生育や収量の向上が期待される.しかし,沖縄県に存在する多様な土壌のケイ酸可給度に関する知見は未だ限られている.そこで本研究では,沖縄県全域の土壌試料の可給態ケイ酸を定量評価するとともに,その規定要因を解明することを目的とした.</p><p>沖縄県全域のサトウキビ畑の表層土合計120点(国頭マージ35点,島尻マージ50点,ジャーガル25点,大東マージ10点)を供試した.可給態ケイ酸は,pH 6.2リン酸緩衝液法で抽出し,塩酸モリブデン酸法により測定した.また,pH, 有機炭素,DCBおよび酸性シュウ酸塩溶解法によるFe, Al, Si濃度などを測定した.</p><p>沖縄県の主要な4種類の土壌試料の可給態ケイ酸の平均値(mg SiO<sub>2</sub> kg<sup>−1</sup>)は,ジャーガル584>島尻マージ398>大東マージ263>国頭マージ148の順となり,国頭マージと大東マージを中心に沖縄県全体の約半分の土壌がケイ酸欠乏であると推測された.また,可給態ケイ酸は,pH, 非晶質遊離酸化鉄,有機炭素などと有意な正の,砂含量と有意な負の相関を示した(p<0.01).さらに,可給態ケイ酸を目的変数,上記理化学性を説明変数として重回帰分析を行ったところ,pHと非晶質鉄酸化物および有機炭素によって全変動の78%を説明できた.</p>

<p>Silicon is a beneficial element for Gramineae plants and is expected to increase the growth and yield of sugarcane (<i>Saccharum officinarum</i>), which is one of the main agricultural products in Okinawa. To evaluate the available silicate (SiO<sub>2</sub>) content and investigate the determining factors behind its presence in the soils of sugarcane fields in Okinawa, we collected 120 soil samples from the surface layer of sugarcane fields (35 Kunigami-mahji (Udults), 50 Shimajiri-mahji (Udalfs), 25 Jahgaru (Orthents), and 10 Daito-mahji (Udults)) and determined their available SiO<sub>2</sub> contents. A phosphate buffer (0.04 M, pH 6.2) was used to extract the available SiO<sub>2</sub> from the soil samples; furthermore, the SiO<sub>2</sub> concentrations in the extracts were determined using a colorimetric method. Selected physicochemical properties, such as pH, the oxalate extractable Fe (Feo), Al (Alo), and Si (Sio), and organic carbon content were also determined for the soil samples.</p><p>The averages of the available silicate contents (mg SiO<sub>2</sub> kg<sup>−1</sup>) were found to be 584, 398, 263, and 148 for Jahgaru, Shimajiri-mahji, Daito-mahji, and Kunigami-mahji, respectively. Around half of the samples, mainly those from Kunigami-mahji and Daito-mahji, were estimated to be SiO<sub>2</sub> deficient. The overall available SiO<sub>2</sub> contents correlated positively with the pH, Feo, and organic C content, and negatively with the sand content (p<0.01). Multi-regression analysis further indicated that the pH, presence of amorphous Fe oxide, and organic matter content were the dominant determining factors, and these three variables explained 78% of the variation in the available SiO<sub>2</sub> content. In conclusion, the available SiO<sub>2</sub> content and the determining factors behind its presence in the soils of sugarcane fields in Okinawa were quantitatively elucidated, and these results will contribute to the establishment of rational soil management, including the application of silicate materials by considering the Si-supplying power of the relevant soils, for sustainable and high-yielding sugarcane production in Okinawa, Japan.</p>

Journal

  • Japanese Journal of Soil Science and Plant Nutrition

    Japanese Journal of Soil Science and Plant Nutrition 90(1), 13-21, 2019

    Japanese Society of Soil Science and Plant Nutrition

Codes

  • NII Article ID (NAID)
    130007602229
  • NII NACSIS-CAT ID (NCID)
    AN00195767
  • Text Lang
    JPN
  • Article Type
    journal article
  • ISSN
    0029-0610
  • NDL Article ID
    029510607
  • NDL Call No.
    Z18-331
  • Data Source
    NDL  J-STAGE  JASI 
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