Effects of 20 years of litter and root manipulations on soil organic matter dynamics

• Main Author: Wig, Jennifer D.
• Other Authors: Lajtha, Kate
• Language: en_US
• Published: 2012
• Subjects: Soils and climate; Soils > Carbon content; Soils > Organic compound content; Soils > Nitrate content; Forest litter; Carbon sequestration
• Online Access: http://hdl.handle.net/1957/30031

Globally, the forestry sector is the second largest contributor of greenhouse gases, and sustainable forest management is a major target of international environmental policy. However, there is the assumption underlying many policy recommendations that an increase in above-ground carbon stocks correspond to long term increases in ecosystem carbon stocks, the majority of which is stored in soils. We analyzed soil carbon and nitrogen dynamics in forest soils that had undergone twenty years of organic inputs manipulations as part of the Detritus Input and Removal Treatment (DIRT) network. There was no statistically significant effect of the rate of litter or root inputs on the carbon or nitrogen in bulk soil, on respiration rates of soil in laboratory incubations, on the non-hydrolyzed fraction of soil organic matter, or on any organic matter associated with any density. However, there is evidence for positive priming due to increased litter inputs; doubling the rate of litter inputs decreased C and N contents of bulk soil and decreased respiration rates of soil. Furthermore, there is evidence that roots influence soil organic matter dynamics more strongly than above-ground inputs. Both of these results trends match data from other DIRT sites, and are supported by the literature. === Graduation date: 2012