PROGRESS IN GEOGRAPHY ›› 2007, Vol. 26 ›› Issue (3): 29-37.doi: 10.11820/dlkxjz.2007.03.004

• Original Articles • Previous Articles     Next Articles

Research on Process and Mechanism of Carbon and Nitrogen Leaching for For est Soils

FANG Huajun1, CHENG Shulan2, YU Guirui1   

  1. stitute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101,China|2 Graduate School of Chinese Academy of Science, Beijing 100049, China
  • Received:2007-02-01 Revised:2007-04-01 Online:2007-05-25 Published:2007-05-25


Abroad attention has been drawn to effects of nitrogen deposition on process of carbon sequestration and depletion for forest ecosystem. However, further research is needed on fate of deposited nitrogen in forest ecosystem, impact of nitrogen increase on conversion process of soil carbon and nitrogen, and dynamics of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in soil solution during pre- and post- soil nitrogen saturation. In this paper, new research advance on fields of soil nitrogen saturation and soil carbon/nitrogen leaching is discussed firstly. Secondly, process and meaning of soil nitrogen saturation are demonstrated by system approach. Inherent response mechanism of nitrogen increase and deposition on the composition and structure change of DOC/ DON is analyzed. Finally, influence of nitrogen increase on conversion of soil inorganic nitrogen and contribution of biotic and abiotic factors on sequestration of deposited nitrogen. To sum up, we think soil nitrogen saturation is a state of available nitrogen increase with time and exceeds capacity of biotic and abiotic hold in soil, and then processes such as nitrogen mineralization, nitrification, leaching and soil pH occur in nonlinear change. Different responses of soil DOC and DON to added nitrogen are attributed to three stages of soil nitrogen saturation, which is related to the persisting time and quantity of nitrogen deposition or added mineralized nitrogen. As far as a certain terrestrial ecosystem is concerned, processes of nitrogen mineralization, nitrification, de - nitrification, immobilization and ammonium fixation in soil need to be deeply studied to make clear status of soil available nitrogen and temporal variability. Furthermore, uncertain questions, possible countermeasures and potential directions are pointed out in three research fields above to provide some reference for researchers.

Key words: dissolved organic matter, nitrogen deposition, soil nitrogen leaching, soil nitrogen saturation, soil nitrogen transformation