Journal of Ecology and Rural Environment ›› 2019, Vol. 35 ›› Issue (5): 644-650.doi: 10.19741/j.issn.1673-4831.2018.0354

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Vertical Distribution of Nitrogen and Its Influencing Factors Under Different Land Use Patterns in a Typical Red Soil Region

ZOU Gang-hua, ZHAO Feng-liang, SHAN Ying   

  1. Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
  • Received:2018-06-25 Online:2019-05-25 Published:2019-06-25


Understanding the role of soil nitrogen migration is an important part of agricultural non-point source pollution research. Studies on the vertical distribution of soil nitrogen and the influence of different land use patterns are very helpful for the investigation of nitrogen migration. 38 undisturbed soil columns (1-m depth)from paddy fields,woodlands and tea gardens were collected from a typical subtropical hilly red soil region. Each soil column was divided into four layers (0-20,>20-30,>40-50 and >70-80 cm)and sampled at 5-cm intervals to determine ammonium,nitrate,total nitrogen and other soil properties. Additionally,the vertical distribution pattern of soil nitrogen in relation to different land uses was investigated. The results show that total soil nitrogen in the paddy fields had mean values of 2.44 (0-20 cm),1.49 (>20-30 cm),1.30 (>40-50 cm)and 1.20 (>70-80 cm),which were significantly higher (P<0.05)than in the woodlands and the tea gardens. There was no significant difference in ammonium among the various land usages. The surface layer (0-20 cm)nitrate content in the paddy fields was significantly higher (P<0.05)than in the tea gardens and the woodlands. Nitrate content in the subsurface layers from the tea gardens was significantly higher (P<0.05)than the paddy fields and the woodlands. It was also found that total soil nitrogen was closely related to nitrate content (r=0.64,P<0.01). Soil organic carbon,soil profile depth and bulk density were important factors affecting the vertical distribution of soil nitrogen. There was a significant positive correlation between soil nitrogen and organic carbon,and a significant negative correlation existed between soil nitrogen and bulk density or soil profile depth (P<0.05),which indicate that the soil nitrogen distribution is influenced by soil properties. The results of this study are helpful to the risk evaluations of water pollution caused by agricultural nitrogen fertilizer application in hilly red soil regions.

Key words: red soil, land use, vertical distribution, non-point source pollution

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