Premium
Low Dissolved Organic Carbon Input from Fresh Litter to Deep Mineral Soils
Author(s) -
Fröberg M.,
Jardine P. M.,
Hanson P. J.,
Swanston C. W.,
Todd D. E.,
Tarver J. R.,
Garten C. T.
Publication year - 2007
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/sssaj2006.0188
Subject(s) - litter , plant litter , forest floor , dissolved organic carbon , soil water , environmental science , total organic carbon , agronomy , chemistry , environmental chemistry , zoology , ecosystem , soil science , ecology , biology
Dissolved organic carbon (DOC) leached from recent litter in the forest floor has been suggested to be an important source of C to the mineral soil of forest ecosystems. To determine the rate at which this flux of C occurs, we have taken advantage of a local release of 14 C at Oak Ridge National Laboratory Reservation, Oak Ridge, TN (35°58′N, 84°16′W). Eight replicate 7‐ by 7‐m plots were established at four field sites on the reservation in an upland oak forest setting. Half of the plots were provided with 14 C‐enriched litter (Δ 14 C ≈ 1000‰), and the other half with near‐background litter (Δ 14 C ≈ 220‰) for multiple years. Differences in the labeled leaf litter were used to quantify the movement of litter‐derived DOC through the soil profile. Soil solutions were collected for several years with tension lysimeters at 15‐ and 70‐cm depths and measured for DOC concentration and 14 C abundance. The net amount of DOC retained between 15 and 70 cm was between 2 and 10 g m −2 yr −1 There were significant effects of the litter additions on the 14 C abundance in the DOC, but the net transport of 14 C from the added litter was small. The difference in Δ 14 C between the treatments with enriched and near‐background litter was only about 130‰ at both depths, which is small compared with the difference in Δ 14 C in the added litter. The primary source of DOC within the mineral soil must therefore have been either the Oe or Oa horizon or the organic matter in the mineral soil. During a 2‐yr time frame, leaching of DOC from recent litter did not have a major impact on the C stock in the mineral soil below 15 cm in this ecosystem.