ISSN:
1435-0661
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
15 N abundance (α15N) of inorganic N in forest soil have been pursued despite its importance for interpretations of plant α15N signatures. To investigate stable N isotope rations in inorganic N, the α15N values and concentrations of total N, NH+ 4, and NO- 3-N of forest mineral soils in four profiles were measured along slop (altitude of 765-870 m) in a coniferous (Japanese red cedar, Cryptomeria japonicaD.Don) forest in Japan. Generally, the α15N values of total N, NH+ 4, and NO- 3-N increased with increasing soil depth. The values of α15N ranged from 1.0 to 6.8‰, 2..5 to 15.6‰, and -14.8 to 5.6‰ for total N, NH+ 4, and NO- 3-N, respectively. Additionally, the α15N values were different between NH+ 4, and NO- 3-N for each soil depth. Thus, it was concluded that the assumptions about inorganic N used in interpretation of plant α15N values were valid. Moreover, on upper slope sites where soil inorganic N was predominantly NH+ 4, the order of α15N was generally total N 〉 NH+ 4 〉 NO- 3-N for each depth, whereas the order of α15N was NH+ 4 〉 total N 〉 NO- 3-N on lower slope sites where NH+ 4 was less dominant as soil inorganic N and relatively high net nitrification rates were measured. Our results suggested that nitrification plays an important role in regulating α15N in forest-soil.
Type of Medium:
Electronic Resource
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