パラグアイ・イグアス地域の不耕起畑におけるダイズ根系分布の実態

• 関 節朗

  国際協力事業団パラグアイ農業総合試験場

• 干場 健

  国際協力事業団パラグアイ農業総合試験場

• BORDON Jorge

  <I>Centro Tecnológico Agropecuario en Paraguay</I>

書誌事項

タイトル別名

• Root Distribution of Soybean Plants in No-tillage Fields in Yguazu District of Paraguay.
• パラグアイ イグアス チイキ ノ フコウキバタケ ニ オケル ダイズ コンケイ ブンプ ノ ジッタイ

抄録

Since the late 1980's, soybean yields in Paraguay had steadily increased with the expansion of no-tillage fields. The average yield has been maintained at about 3t/ha for nearly 10 years. However, the increase of yield has shown a limitation and recently the yield has even tended to decrease. Although the causes of this phenomenon have not been elucidated yet, it is considered that long-term no-tillage practice adversely affects the soil conditions, resulting in an inhibition of soybean root development. The characteristics of the soybean root distribution in 11 fields depending on the differences in the duration of application of the no-tillage practice, differences in the crops preceding the cultivation of soybean and soil types were examined. In the majority of the no-tillage fields, more than 50% of the soybean tap roots did not elongate vertically in the deep soil profile, and lateral roots in surface soil grew vigorously near the soil surface, which resulted in a concentrated root distribution only in the uppermost soil layers. On the other hand, soybean tap roots in the year immediately after reclamation and in plowed fields showed a relatively deeper penetration with improved vertical root distribution. The occurrence of soybean plants whose tap roots did not penetrate into deep soil layers increased with the soil hardness and phosphorus accumulation in the uppermost layers. These results suggest that in the no-tillage fields the adverse soil conditions associated with the increase of soil hardness and phosphorus accumulation in the uppermost soil layers inhibited soybean root development in the deeper soil layers, and resulted in the recent decrease of soybean yields in Yguazu.

収録刊行物

• 熱帯農業

  熱帯農業 45 (1), 33-37, 2001

  日本熱帯農業学会

キーワード

• 根系分布
• ダイズ
• 土壌硬度
• 不耕起栽培
• リン酸集積

詳細情報

• CRID: 1390001206360886528
• NII論文ID: 110003709773
• NII論文ID: 130004373731
• NII書誌ID: AN00199779
• DOI: 10.11248/jsta1957.45.33
• ISSN: 21850259
• ISSN: 00215260
• NDL書誌ID: 5707031
• Web Site: http://id.ndl.go.jp/bib/5707031
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I5707031
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可