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Soil Science Society of America Journal Abstract - NUTRIENT MANAGEMENT & SOIL & PLANT ANALYSIS

Reduction of Ammonia Volatilization from Urea by a Floating Duckweed in Flooded Rice Fields


This article in SSSAJ

  1. Vol. 73 No. 6, p. 1890-1895
    Received: July 9, 2008

    * Corresponding author(s): lisar2002@zju.edu.cn
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  1. Hua Lia,
  2. Xinqiang Liang *b,
  3. Yanfeng Lianc,
  4. Lei Xua and
  5. Yingxu Chena
  1. a Key Laboratory of Non-point, Source Pollution Control, Ministry of Agriculture and Institute of Environmental Science and Technology, Zhejiang University, HangZhou 310029, China
    b Key Laboratory of Water Pollution Control and Environmental Safety Technology, Zhejiang Province, HangZhou 310029, China
    c Research Academe of Environment and Science of Zhejiang Province, HangZhou 310007, China


Effective nutrient management to reduce high N losses and to improve N use efficiency has been an important focus of agricultural and environmental science research. Understanding the influence of duckweed (Lemna minor L.), a common floating macrophyte in flooded rice (Oryza sativa L.) fields, on NH3 volatilization and grain yield is required for better management of applied N fertilizer. We conducted an on-farm experiment with three levels of urea (0, 90, 180 kg urea N ha−1) applied alone or in combination with duckweed. Our results indicate that total ammoniacal-N concentration, pH, and temperature of the floodwater were significantly lower in the plots with a duckweed cover. As a consequence, NH3 volatilization rates were reduced by duckweed from 20.0 to 53.7% and from 19.0 to 33.2% in plots supplied with 90 and 180 kg urea-N ha−1, respectively. Duckweed increased rice grain yields by approximately 0.7 and 0.7 Mg ha−1 (9.8 and 9.4%) in plots supplied with 90 and 180 kg urea N ha−1, respectively. Ammonia losses from urea-N applications can be reduced and N use efficiencies can be improved by the presence of duckweed in flooded rice fields.

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