HR: 1340h
AN: B23D-1593    [Abstracts]
TI: The Origin of DIRT (Detrital Input and Removal Treatments): the Legacy of Dr. Francis D. Hole
AU: * Townsend, K L
EM: zoeykim@aol.com
AF: Dept. Environmental Sciences, Oregon State University, Corvallis, OR 97331, United States
AU: Lajtha, K
EM: lajthak@science.oregonstate.edu
AF: Dept. Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, United States
AU: Caldwell, B
EM: bruce.caldwell@oregonstate.edu
AF: Dept. Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, United States
AU: Sollins, P
EM: phil.sollins@oregonstate.edu
AF: Dept. Forest Science, Oregon State University, Corvallis, OR 97331, United States
AB: Soil organic matter (SOM) plays a key role in the cycling and retention of nitrogen and carbon within soil. Both above and belowground detrital inputs determine the nature and quantity of SOM. Studies on detrital impacts on SOM dynamics are underway at several LTER, ILTER and LTER-affiliated sites using a common experimental design, Detrital Input and Removal Treatments (DIRT). The concept for DIRT was originally based on experimental plots established at the University of Wisconsin Arboretum by Dr. Francis D. Hole in 1956 to study the effects of detrital inputs on pedogenesis. These plots are located on two forested sites and two prairie sites within the arboretum. Manipulations of the forested sites include double litter, no litter and removal of the O and A horizons. Manipulations of the prairie sites include harvest, mulch, bare and burn. These original treatments have largely been maintained since 1956. After 40 years of maintenance, there were significant differences in soil carbon between the double and no litter plots. The double litter plots had increased by nearly 30% while the no litter plots had decreased over 50%. The original DIRT plots are now 50 years old and have been re-sampled, where possible, for total carbon and nitrogen, labile and recalcitrant carbon fractions, net and gross nitrogen mineralization rates, and SOM bioavailability through CO2 respiration. The soils were fractionated by density to examine the role of carbon in each density fraction. The mean age of carbon in each fraction was determined by radiocarbon dating. This sampling and analysis is of special significance because it provides a glimpse into the future SOM trajectories for the new DIRT sites: Harvard Forest (MA), Bousson (PA), Andrews Experimental Forest (OR) and Sikfokut (Hungary).
DE: 0428 Carbon cycling (4806)
DE: 0470 Nutrients and nutrient cycling (4845, 4850)
DE: 0486 Soils/pedology (1865)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting