PARENT SESSION
Oral Session 3: Biogeochemistry I: Litter and Decomposition.
Presiding: J Dilustro
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room A 107.

Relative importance of root litter as an input of soluble organic C to forest nutrient cycling.

Uselman, Shauna^*,1, Qualls, Robert¹, Kluck, Juliane¹, ¹ University of Nevada-Reno, Reno, NV, USA

ABSTRACT- Very few studies have examined inputs of soluble organic C in forests, and no study has ever examined inputs from root litter. Root litter could contribute relatively large amounts of C to forest ecosystem nutrient cycling. In this study, we determined the fate of the soluble organic material leaching from root litter, compared to leaf litter. For this, we added ¹⁴C-labeled root and leaf material to soil microcosm cores, we trapped respired ¹⁴CO₂, we analyzed leachate from simulated snowmelt, and we extracted soil cores in layers for translocated ¹⁴C material. Preliminary data shows that a greater percentage of the C lost from roots is greater (65-74%) than from leaves (55%), as a relative proportion of total C lost to leaching versus respiration. In addition, more C is lost from deeper roots (74% at 40 cm depth) as compared to shallow roots (65% at 10 cm depth). This study indicates that root litter contributes more soluble organic C to the soil rhizosphere than leaf litter as compared to the amount of C lost to respiration.

Key words: forest ecosystem, root litter, carbon