Nitrogen biogeochemistry of three hardwood ecosystems in the Adirondack Region of New York
Mitchell, M; Driscoll, C; Owen, J; Schaefer, D; Michener, R; Raynal, D
| HERO ID | 97988 |
|---|---|
| In Press | No |
| Year | 2001 |
| Title | Nitrogen biogeochemistry of three hardwood ecosystems in the Adirondack Region of New York |
| Authors | Mitchell, M; Driscoll, C; Owen, J; Schaefer, D; Michener, R; Raynal, D |
| Journal | Biogeochemistry |
| Volume | 56 |
| Issue | 2 |
| Page Numbers | 93-133 |
| Abstract | The biogeochemistry of nitrogen (N) was evaluated for three forest ecosystems [Woods Lake (WL), Pancake-Hall Creek (PHC) and Huntington Forest (HF)] in the Adirondack region of New York, U.S.A. to evaluate the response of a range of N atmospheric inputs and experimental N additions. Bulk N deposition was higher at sites in the west than those in the central and eastern Adirondacks. These higher atmospheric N inputs were reflected in higher bulk throughfall fluxes of N (WL and PHC, 10.1 and 12.0 kg N ha(-1) yr(-1), respectively) in the western Adirondacks than at HF (4.6 kg N ha(-1) yr(-1)) in the central Adirondacks. Nitrogen was added to plots as (NH4)(2)SO4 at 14 and 28 kg N ha(-1) yr(-1) or as HNO3 at 14 kg N ha(-1) yr(-1). Litter decomposition rates of Fagus grandifolia and Acer rubrum were substantially higher at WL and PHC compared to HF but were not affected by experimental N additions. Results using mineral soil bags showed no effects of N addition on N and C concentrations in soil organic matter, but C and N concentration increases were less at WL and PHC compared to HF. Soil solution nitrate (NO3-) concentrations at 15-cm depth in the reference plots were higher at PHC than at WL and HF while at 50-cm concentrations were higher at PHC and WL than at HF. The reference plots at the two sites (WL and PHC) with the highest atmospheric inputs of N exhibited lower N retention (53 and 33%, respectively) than HF (68%) in reference plots. The greatest increase in NO3- loss in response to the experimental treatments occurred at HF where the HNO3 additions resulted in the highest NO3- concentrations and lowest N retentions. In contrast, at WL and PHC increases in soil water NO3- were not evident in response to experimental N additions. The results suggest that the two sites (WL and PHC) in the western Adirondacks did not respond to additional N inputs although they have experienced elevated atmospheric N inputs and higher N drainage losses in reference plots than the HF site in the central Adirondacks. Some of these differences in site response may have also been a function of stand age of WL and PHC that were younger (24 and 33 years, respectively) than the HF (age similar to 70). Highest NO3- fluxes in the reference plots across the sites corresponded to higher delta N-15 values in soil and plants. An experimental addition experiment at PHC found that the forest floor and the mineral soil were the largest sinks for experimentally added N. |
| Doi | 10.1023/a:1013001710569 |
| Wosid | WOS:000172448100001 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Keyword | atmospheric deposition; decomposition; dissolved organic nitrogen; experimental additions; forests; mass balances; N-15 isotopes; nitrate; nitrogen; soils |
| Is Qa | No |