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This article in JEQ

  1. Vol. 32 No. 6, p. 1965-1977
     
    Received: July 14, 2002


    * Corresponding author(s): yanai@kais.kyoto-u.ac.jp
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doi:10.2134/jeq2003.1965

Spatial Variability of Nitrous Oxide Emissions and Their Soil-Related Determining Factors in an Agricultural Field

  1. Junta Yanai *a,
  2. Takuji Sawamotob,
  3. Taku Oea,
  4. Kanako Kusab,
  5. Keisuke Yamakawac,
  6. Kazunori Sakamotoc,
  7. Takahiko Naganawad,
  8. Kazuyuki Inubushic,
  9. Ryusuke Hatanob and
  10. Takashi Kosakia
  1. a Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake, Sakyo, Kyoto 606-8502, Japan
    b Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
    c Faculty of Horticulture, Chiba University, Matsudo, Chiba 271-8510, Japan
    d Faculty of Life and Environmental Science, Shimane University, Matsue Shimane 690-8504, Japan

Abstract

To evaluate spatial variability of nitrous oxide (N2O) emissions and to elucidate their determining factors on a field-scale basis, N2O fluxes and various soil properties were evaluated in a 100- × 100-m onion (Allium cepa L.) field. Nitrous oxide fluxes were determined by a closed chamber method from the one-hundred 10- × 10-m plots. Physical (e.g., bulk density and water content), chemical (e.g., total N and pH), and biological (e.g., microbial biomass C and N) properties were determined from surface soil samples (0–0.1 m) of each plot. Geostatistical analysis was performed to examine spatial variability of both N2O fluxes and soil properties. Multivariate analysis was also conducted to elucidate relationships between soil properties and observed fluxes. Nitrous oxide fluxes were highly variable (average 331 μg N m−2 h−1, CV 217%) and were log–normally distributed. Log-transformed N2O fluxes had moderate spatial dependence with a range of >75 m. High N2O fluxes were observed at sites with relatively low elevation. Multivariate analysis indicated that an organic matter factor and a pH factor of the principal component analysis were the main soil-related determining factors of log-transformed N2O fluxes. By combining multivariate analysis with geostatistics, a map of predicted N2O fluxes closely matched the spatial pattern of measured fluxes. The regression equation based on the soil properties explained 56% of the spatially structured variation of the log-transformed N2O fluxes. Site-specific management to regulate organic matter content and water status of a soil could be a promising means of reducing N2O emissions from agricultural fields.

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Copyright © 2003. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyASA, CSSA, SSSA