280-4 Switchgrass Ecotype Contributions to Soil Organic Carbon, Deep Soil Microbial Community Composition and Rhizodeposit Uptake.

See more from this Division: SSSA Division: Soil Fertility and Plant Nutrition
See more from this Session: Symposium--the Rhizosphere

Tuesday, November 8, 2016: 3:05 PM
Phoenix Convention Center North, Room 129 AB

Catherine E. Stewart1, Damaris Roosendaal2, Karolien Denef3, Louise H. Comas1, Gautam Sarath4, Virginia L. Jin5, Marty R. Schmer6 and Madhavan Soundararajan7, (1)USDA-ARS, Fort Collins, CO
(2)Soil Management and Sugar Beet Research Unit, USDA-ARS, Fort Collins, CO
(3)Department of Chemistry, Central Instrument Facility, Colorado State University, Fort Collins, CA
(4)Grain, Forage, and Bioenergy Research Unit, USDA-ARS, Lincoln, NE
(5)UNL- East Campus, USDA-ARS, Lincoln, NE
(6)UNL, East Campus, USDA-ARS, Lincoln, NE
(7)Department of Biochemistry, University of Nebraska, Lincoln, NE
Abstract:
Perennial cellulosic bioenergy crops such as switchgrass (Panicum virgatum L.) can improve marginally productive cropland and sequester C throughout the soil profile. Switchgrass ecotypes vary in their belowground plant allocation and rooting characteristics which could impact soil C cycling and rhizodeposit contributions to microbial community abundance and composition. We report the results of a 1 year field experiment following plant uptake, root biomass, and rhizodeposit uptake after a  pulse-chase 13C labeling experiment of two switchgrass cultivars, Kanlow and Summer. Active microbial community composition and rhizodeposit C uptake were different between the two cultivars, and reflected differences in root structure. The microbial community associated with the thinner roots of Summer had rhizodeposit C uptake associated primarily with saprotrophic fungi. Rhizodeposit C from Kanlow’s thicker roots was processed primarily by G- bacteria. These results suggest that plant-specific interactions with the microbial community can induce a variety of C sequestration mechanisms.

See more from this Division: SSSA Division: Soil Fertility and Plant Nutrition
See more from this Session: Symposium--the Rhizosphere