TITLE:
Soil Pedon Carbon and Nitrogen Data for Alaska: An Analysis and Update
AUTHORS:
Gary J. Michaelson, Chien-Lu Ping, Mark Clark
KEYWORDS:
Soil Carbon; Soil Nitrogen; Arctic Soils; Pedotransfer Functions; Permafrost Soils
JOURNAL NAME:
Open Journal of Soil Science,
Vol.3 No.2,
June
10,
2013
ABSTRACT: We combined C and N related pedon data
from the USDA-NRCS National Cooperative Soil Survey Soil Characterization Database with data from the
University of Alaska Fairbanks (UAF) northern soils research program, representing
58 and 30 years of field work, respectively. Carbon and N data from 117 UAF
pedons were added to 541 pedons from the USDA-NRCS data set for a total of 658.
Missing carbon (C), nitrogen (N) and related data were added to nearly all of
the USDA-NRCS Arctic region pedons from unpublished UAF data. We present relationships
among soil parameters of the data set that are necessary for calculation of
pedon soil organic C and N stores. These new relationships are necessary for better estimating missing
soil bulk density (Db) from measured soil organic C by high-temperature combustion (SOCHTC) and for
conversion of acid chromate reduction soil organic carbon (SOCACR)
to SOCHTC. For the USDA-NRCS data, missing Db data were estimated
and SOCACR corrected to SOCHTC using the new functional
relationships
developed. This allowed for pedon SOC and N stores to be calculated for 609 and
468 Alaska
pedons respectively,
the most available to-date. Additionally, functional relationships were
developed for data within soil orders to estimate total SOCHTC and N
stores in pedons with missing surface organic horizons where only thicknesses
were known. These relationships are presented in order to fill-in missing data
and to better define the existing data set for future use. Some 1904 missing Db
data points and 1612 corrected SOCHTC data points were added to the
total of 4240 points in the 609 pedons that constitute the updated dataset.
When O-layer thickness functions developed here were used, SOC and N stores
were calculated for an additional 137 and 184 pedons respectively.