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Soil Carbon and Nitrogen Changes Under Douglas‐fir With and Without Red Alder
Author(s) -
Rothe Andreas,
Cromack Kermit,
Resh Sigrid C.,
Makineci Ender,
Son Yowhan
Publication year - 2002
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/sssaj2002.1988
Subject(s) - alder , mineralization (soil science) , zoology , nitrogen , significant difference , soil carbon , accretion (finance) , soil water , chemistry , botany , horticulture , biology , ecology , mathematics , physics , astrophysics , statistics , organic chemistry
We sampled pure Douglas‐fir (DF) [ Pseudotsuga menziesii (Mirb.) Franco] and mixed red alder ( Alnus rubra Bong.)(RA) and DF (RA/DF) stands in 1980 and in 1999 to investigate the influence of RA on soil C and N pools. In RA/DF plots with 25% RA, the soil N pool to a 45‐cm depth increased significantly ( P < 0.05) by 190 g N m −2 , corresponding to 10 g N m −2 yr −1 accretion. The average between treatment soil N difference in 1999 was 166 g m −2 , representing N accretion of 8.7 g m −2 yr −1 In pure DF plots, the soil N pool remained nearly constant. Resin N mineralization in RA/DF plots was about ten fold greater than on pure DF plots, but the enhanced resin N availability did not affect DF foliar N concentration. Temporal plot pairing was necessary within this landscape with high spatial variability to detect significant changes in soil N pools, and only large effects, such as N addition by RA, could be identified with statistical significance. Minimum detectable difference (MDD) estimates for mean total soil C differences in RA/DF plots showed that it would require about 30 more years of C accretion to detect differences at P < 0.05. Conversely, total soil N accretion in RA/DF plots was 28% greater than the MDD after 19 yr.