Fine root production and nutrient content in wet and moist arctic tundras as influenced by chronic fertilization
- 145 Downloads
We used ingrowth cores to estimate fine root production in organic soils of wet sedge and moist tundra ecosystems near Toolik Lake on Alaska's North Slope. Root-free soil cores contained in nylon mesh tubes (5 cm diameter, 20–30 cm long) were placed in control and chronically fertilized (N plus P) plots in mid-August 1994 and were retrieved 1 year later. Estimated fine root production in control plots was 75 g m−2 year−1 in wet sedge and 56 g m−2 year−1 in moist tussock tundra. Fine root production in fertilized plots was 85 g m−2 year−1 in wet sedge and 67 g m−2 year−1 in moist tussock tundra. Although our estimates of fine root production were higher on fertilized than control plots, differences were not statistically significant within either tundra type. Comparisons between our estimates of fine root production and other estimates of aboveground (plus rhizome) production on the same (wet sedge tundra) or similar (moist tussock tundra) plots suggest that fine root production was about one-third of total net primary production (NPP) under non-fertilized conditions and about one-fifth of total NPP under chronic fertilization. Fine root N and P concentrations increased with fertilization in both tundra types, but P concentrations increased more than N concentrations in wet sedge tundra, whereas relative increases in N and P concentrations in moist tundra roots were similar. These data are consistent with other studies suggesting that NPP in wet sedge tundra is often P limited and that co-limitation by N and P is more important in moist tussock tundra.
Unable to display preview. Download preview PDF.
- Aspila K I, Agemian H and Chau A S Y 1976 A semi-automated method for the determination of inorganic and total phosphate in sediments. Analyst 101, 187-197.Google Scholar
- Chapin F S III, Miller P C, Billings W D and P I Coyne 1980 Carbon and nutrient budgets and their control in coastal tundra. In An Arctic Ecosystem: The Coastal Tundra at Barrow, Alaska. US IBP Synthesis Series, Volume 12. Eds. J Brown, P C Miller, L L Tieszen and F L Bunnel. pp 458-483, Dowden, Hutchinson and Ross. Stroudsburg, PA.Google Scholar
- Chapin F S III, Shaver G R, Giblin A E, Nadelhoffer K J and Laundre J A 1995 Responses of Arctic tundra to experimental and observed changes in climate. Ecology 76, 694-711.Google Scholar
- Callaghan T V, Headley A D and Lee J A 1991 Root function related to the morphology, life history and ecology of tundra plants. In Plant Root Growth: An Ecological Perspective Ed. D. Atkinson. pp 311-340, Blackwell Scientific Publications, Oxford, UK.Google Scholar
- Cuevas E and Medina E 1988 Nutrient dynamics within Amazonian forests. II. Fine root growth, nutrient availability and leaf litter decomposition. Oecologia 76, 222-235.Google Scholar
- Giblin A E, Nadelhoffer K J, Shaver G R, Laundre J and McKerrow A 1991 Biogeochemical diversity along a topographic gradient in a tundra landscape. Ecol. Monogr. 61, 415-436.Google Scholar
- Jordan C F and Escalante G 1980 Root productivity in an Amazonian rain forest. Ecology 61, 14-18.Google Scholar
- Nadelhoffer K J, Giblin A E, Shaver G R and Laundre J 1991 Effects of temperature and organic matter quality on C, N and P mineralization in soils from arctic ecosystems. Ecology 72, 242-253.Google Scholar
- Persson H 1983 The distribution and productivity of fine roots in boreal forests. Plant Soil 71, 87-101.Google Scholar
- Shaver G R and Billings D W 1975 Root production and turnover in a wet tundra ecosystem, Barrow, Alaska. Ecology 56, 401-410.Google Scholar
- Shaver G R and Cutler J 1979 The vertical distribution of phytomass in cotton-grass tundra. Arctic Alpine Res. 18, 261-268.Google Scholar
- Shaver G R, Johnson L C, Cades D H, Murray G, Laundre J A, Rastetter E B, Nadelhoffer K J and Giblin A E 1997 Biomass accumulation and CO2 flux in three Alaskan wet sedge tundras: Responses to nutrients, temperature, and light. Ecol. Monogr. 68, 75-97.Google Scholar