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Soil Soluble Nitrogen Availability across an Elevation Gradient in a Cold‐Temperate Forest Ecosystem
Author(s) -
Shan Shan,
Coleman Mark,
Kimsey Mark
Publication year - 2014
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2013.08.0330nafsc
Subject(s) - temperate climate , nutrient , ecosystem , temperate forest , forest ecology , temperate rainforest , nitrogen , agronomy , environmental science , ecology , chemistry , biology , organic chemistry
Little is known about the distribution of plant‐available N with elevation or under different plant–mycorrhizal associations. Our study evaluated soil amino acids, NH 4 + , and NO 3 − pools, soil properties, and enzyme activities under three types of plant–mycorrhizal associations along a cold‐temperate forest elevation gradient. We found that amino acid concentrations increased as elevation increased (0.21 mg kg −1 per 100 m), while NH 4 + and NO 3 − pool sizes remained constant (0.9–3 mg kg −1 for NH 4 + –N and 0–0.5 mg kg −1 for NO 3 − –N). Similar pool sizes and composition of soil soluble N were found under three plant–mycorrhizal associations. We concluded that amino acids, as a major component of soil N, increasingly supplement inorganic N as elevation increases. This study provides evidence of the importance of amino acids in soil soluble N of northern Idaho cold‐temperate forest ecosystems, especially at high elevations, suggesting the need to include organic amino acids in future studies of forest nutrient availability.