Composition and decomposition of rhizoma peanut (arachis glabrata benth) belowground biomass

Authors: SANTOS, ERICK - UNIVERSITY OF FLORIDA; DUBEUX, JOSE - UNIVERSITY OF FLORIDA; SOLLENBERGER, LYNN - UNIVERSITY OF FLORIDA; SIQUEIRA, MICHELLE - UNIVERSITY OF FLORIDA; VAN CLEEF, FLAVIA - UNIVERSITY OF FLORIDA; Jaramillo, David; ZAGATO, LUANA - UNIVERSITY OF FLORIDA; RUIZ-MORENO, MARTIN - UNIVERSITY OF FLORIDA; GARCIA, CARLOS - UNIVERSITY OF FLORIDA

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2022
Publication Date: 6/15/2022
Citation: Santos, E., Dubeux, J., Sollenberger, L., Siqueira, M., Van Cleef, F., Jaramillo, D.M., Zagato, L., Ruiz-Moreno, M., Garcia, C. 2022. Composition and decomposition of rhizoma peanut (arachis glabrata benth) belowground biomass. Scientific Reports. https://doi.org/10.1038/s41598-022-14001-7.
DOI: https://doi.org/10.1038/s41598-022-14001-7

Interpretive Summary: Roots and rhizomes play an important role in nutrient cycling, however, few studies investigate how their decomposition pattern is affected by defoliation and time of the year. This 2-year study evaluated belowground litter composition and decomposition of a warm-season perennial legume, rhizoma peanut (RP; Arachis glabrata Benth.), managed either under continuous stocking or in 56-d harvest intervals. A trial with 168 d of incubation was performed to estimate remaining biomass, remaining N, C:N ratio, acid detergent fiber (ADF), and acid detergent insoluble N (ADIN). Additionally, three 56-d incubations were performed to evaluate the disappearance coefficient (B0) and relative decay rate (k) along each year. After 168 d, there was 21 and 60% left of the initial biomass and initial N, respectively. Relative decay rate for OM and N were 0.0088 and 0.0035 g g-1 d-1, respectively. Carbon-to-N ratio decreased from 29 at day 0 to 17 at day 168. Concentration of ADIN increased from 6.9 to 19.3 g kg-1, plateauing at day 79. The B0 and k for remaining OM and N were greater during the late season harvest interval than the early season harvest and could be explained by greater N concentration and lower C:N ratio. The rapid decomposition, difference in C:N ratio from day 0 to day 168, and the increase in ADIN indicate great amounts of root-rhizome soluble C at initial incubation. This data will be useful to estimate RP root-rhizome turnover and its contribution to grassland ecosystems.

Technical Abstract: Roots and rhizomes play an important role in nutrient cycling, however, few studies investigate how their decomposition pattern is affected by defoliation and time of the year. This 2-yr. study evaluated belowground litter composition and decomposition of a warm-season rhizomatous perennial legume, rhizoma peanut (RP; Arachis glabrata Benth.), managed either under continuous stocking or in 56-d harvest intervals A trial with 168 d of incubation was performed to estimate remaining biomass, remaining N, C:N ratio, acid detergent fiber (ADF), and acid detergent insoluble N (ADIN). Additionally, three 56-d incubations were performed to evaluate the disappearance coefficient (B0) and relative decay rate (k) along each year. There was no significant difference among treatments for the 168-d incubation period (P > 0.05). After 168 d, there was 21 and 60% left of the initial biomass and initial N, respectively. Relative decay rate for OM and N were 0.0088 and 0.0035 g g-1 d-1, respectively. Carbon-to-N ratio decreased from 29 at day 0 to 17 at day 168. Concentration of ADIN increased from 6.9 to 19.3 g kg-1, plateauing at day 79. The B0 and k for remaining OM and N were greater during the late season harvest interval than the early season harvest and could be explained by greater N concentration and lower C:N ratio. The rapid decomposition, difference in C:N ratio from day 0 to day 168, and the increase in ADIN indicate great amounts of root-rhizome soluble C at initial incubation. This data will be useful to estimate RP root-rhizome turnover and its contribution to grassland ecosystems.