02714nam a2200253 a 450000100080000000500110000800800410001910000170006024501410007726001710021852018590038965000120224865000110226065000110227165000130228270000240229570000180231970000190233770000140235670000220237070000190239270000200241170000290243121196692020-01-31       2019    bl uuuu     u00u1 u    #d1 aSILVA, L. S.  aAbove and Belowground Biomass Characteristics of Rhizoma Peanut Entries and Their Relationship with Soil C and N.h[electronic resource]  aIn: ASA, CSSA & SSSA INTERNATIONAL ANNUAL MEETING, 2019, San Antonio. Embracing the digital environment: abstracts [eletrônico]... San Antonio: ASA; CSSA; SSSAc2019  aIn forage systems, soil C and N are affected by many factors including above- and belowground biomass, root exudation, defoliation management, and tissue turnover dynamics. There is need to understand the main drivers of soil C and N accumulation under perennial forages, especially those factors associated with differences in growth and canopy characteristics. The objective was to determine soil C and N status and their relationship with above- and belowground characteristics of six rhizoma peanut (RP, Arachis glabrata) entries. Treatments were Apalachee, Chico, Ecoturf, Ona33, Peace, and Tito RP arranged in four replicates of a randomized complete block design. Stands were planted in 2010 and harvested twice per year after establishment. The area was previously a long-term bahiagrass (BH, Paspalum notatum) sward. Herbage accumulation (HA) and root-rhizome mass (RRM) and accumulation rate (RRA) were measured in 2016 and 2017. Existing litter and soil to 0-5, 5-10, and 10-20-cm depths were sampled in September and December 2018. Herbage and litter samples were harvested using two, 0.25-m2 quadrats per plot. Three 10-cm diameter cores (20-cm depth) were taken per plot to measure RRM, while RRA was measured using ingrowth cores. Soil C and N concentrations were determined by dry combustion. Among entries, HA ranged from 6.7 to 10.5 Mg ha-1, RRM from 5.5 to 8.6 Mg ha-1, RRA from 10 to 33 kg ha-1 d-1, and litter mass from 1800 to 2300 kg ha-1. Litter mass and RRA were negatively correlated to C and N stocks in the 0-5 cm layer and positively correlated with those in the 10-20 cm layer. This may be due to mineralization of nutrients in surface soil and use by plants to accumulate biomass, followed by release of exudates and tissue turnover at depth. Soil C and N stocks were less responsive to sward characteristics than expected.  aBiomass  aCarbon  aForage  aNitrogen1 aSOLLENBERGER, L. E.1 aCOOLEY, K. D.1 aKOHMANN, M. M.1 aARYAL, P.1 aPEDREIRA, B. C. e1 aPEDROSO, G. B.1 aSILVEIRA, M. L.1 aDUBEUX JÚNIOR, J. C. B.