Influence of Agricultural Activity on Nitrogen Budget in Chinese and Japanese Watersheds

S. D. Kimura, Xiao Yuan Yan, R. Hatano, A. Hayakawa, K. Kohyama, Chao Pu Ti, Mei Hua Deng, M. Hojito, S. Itahashi, K. Kuramochi, Zu Cong Cai, M. Saito

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Abstract

To analyze the effect of agricultural activity on nitrogen (N) budget at the watershed scale, a comparative study was conducted at two Japanese watersheds, the Shibetsu River watershed (SRW) and Upper-Naka River watershed (UNRW), and one Chinese watershed, the Jurong Reservoir watershed (JRW). The total area and the proportion of agricultural area (in parentheses) of the watersheds were 685 (51%), 1 299 (21%), and 46 km2 (55%) for SRW, UNRW, and JRW, respectively. The main agricultural land use in SRW was forage grassland, while paddy fields occupied the highest proportion of cropland in UNRW (11% of total area) and JRW (31% of total area). The farmland surplus N was 61, 48, and 205 kg N ha-1 year-1 for SRW, UNRW, and JRW, respectively. The total input and output for the whole watershed were 89 and 76, 83 and 61, and 353 and 176 kg N ha-1 year-1 for SRW, UNRW, and JRW, respectively. The proportion of discharged N to net anthropogenic N input was 31%, 37%, and 1.7% for SRW, UNRW, and JRW, respectively. The two watersheds in Japan showed similar proportions of discharged N to those of previous reports, while the watershed in China (JRW) showed a totally different characteristic compared to previous studies. The high N input in JRW did not increase the amount of discharged N at the outlet of the watershed due to high proportions of paddy fields and water bodies, which was an underestimated N sink at the landscape scale.

Original languageEnglish
Pages (from-to)137-151
Number of pages15
JournalPedosphere
Volume22
Issue number2
DOIs
Publication statusPublished - 2012 Apr

Keywords

  • Anthropogenic nitrogen input
  • Denitrification
  • Discharged nitrogen
  • Land use
  • Nitrogen balance

ASJC Scopus subject areas

  • Soil Science

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    Kimura, S. D., Yan, X. Y., Hatano, R., Hayakawa, A., Kohyama, K., Ti, C. P., Deng, M. H., Hojito, M., Itahashi, S., Kuramochi, K., Cai, Z. C., & Saito, M. (2012). Influence of Agricultural Activity on Nitrogen Budget in Chinese and Japanese Watersheds. Pedosphere, 22(2), 137-151. https://doi.org/10.1016/S1002-0160(12)60001-0