My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in JEQ

  1. Vol. 40 No. 4, p. 1266-1272
     
    Received: Aug 25, 2010
    Published: July, 2011


    * Corresponding author(s): maie@vmas.kitasato-u.ac.jp
 View
 Download
 Alerts
 Permissions
 Share

doi:10.2134/jeq2010.0374

Influence of Irrigated Paddy Fields on the Fluorescence Properties of Fluvial Dissolved Organic Matter

  1. Youichiro Abea,
  2. Nagamitsu Maie *b and
  3. Eikichi Shimab
  1. a Graduate School of Veterinary Medicine & Animal Sciences, Kitasato Univ., Towada, Aomori Prefecture 034-8628, Japan
    b School of Veterinary Medicine, Kitasato Univ., Towada, Aomori Prefecture 034-8628, Japan. Assigned to Associate Editor Robert Cook

Abstract

This study investigated seasonal and geographical variation in the fluorescence properties of dissolved organic matter (DOM) in a river system that includes rice paddy fields in its watershed. The river system covers a northern area of the main island of Japan, and between 6 and 45% the watershed area of the tributaries is paddy fields. Water samples were collected monthly from eight tributaries for 1 yr, and the fluorescence properties of DOM were monitored by combined excitation-emission matrix (EEM) and parallel factor analysis. The EEM was statistically decomposed into six fluorescence components with different environmental dynamics. The relative proportion of these components varied with season and geographic location, the former having a greater effect than the latter. Seasonal variation is largely attributed to changes in the source of DOM associated with irrigated rice cultivation practice. The fluorescence component composition showed a stronger autochthonous signature, which varied over a wider range during off-cropping period (October–April) than cropping period (May–September). During the cropping period, a large amount of allochthonous DOM with relatively similar quality was transported into river water from flooded paddy fields and masked the variability in the quality of DOM among tributaries. Therefore, irrigated rice cropping practices are considered to be one of major factors that influence seasonal and geographical variation of fluvial DOM composition.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © 2011. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.