Dynamics of soil inorganic nitrogen and their responses to nitrogen additions in three subtropical forests, south China
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
Three forests with different historical land-use, forest age, and species assemblages in subtropical China were selected to evaluate current soil N status and investigate the responses of soil inorganic N dynamics to monthly ammonium nitrate additions. Results showed that the mature monsoon evergreen broadleaved forest that has been protected for more than 400 years exhibited an advanced soil N status than the pine (Pinus massoniana) and pine-broadleaf mixed forests, both originated from the 1930's clear-cut and pine plantation. Mature forests had greater extractable inorganic N pool, lower N retention capacity, higher inorganic N leaching, and higher soil C/N ratios. Mineral soil extractable NH4+-N and NO3--N concentrations were significantly increased by experimental N additions on several sampling dates, but repeated ANOVA showed that the effect was not significant over the whole year except NH4+-N in the mature forest. In contrast, inorganic N (both NH4+-N and NO3--N) in soil 20-cm below the surface was significantly elevated by the N additions. From 42% to 74% of N added was retained by the upper 20 cm soils in the pine and mixed forests, while 0%-70% was retained in the mature forest. Our results suggest that land-use history, forest age and species composition were likely to be some of the important factors that determine differing forest N retention responses to elevated N deposition in the study region.
Originalsprog | Engelsk |
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Tidsskrift | Journal of Environmental Sciences |
Vol/bind | 18 |
Udgave nummer | 4 |
Sider (fra-til) | 752-759 |
Antal sider | 8 |
ISSN | 1001-0742 |
Status | Udgivet - 2006 |
ID: 8024539