Carbon Dioxide Flux from Bermudagrass Turf as Affected by Nitrogen Rate

Increasing carbon dioxide (CO 2 ) concentrations have contributed to global climate change. Atmospheric CO 2 concentration has increased by ≈43%, from 280 ppmv in 1850 to 400 ppmv in 2015. This increase is expected to alter the distribution of C among the atmosphere, vegetation, and soils. Despite its large‐scale presence in the urban ecosystem, the role of turfgrasses in C cycling has received limited attention, and studies with warm‐season turfgrasses are lacking. The objective of this study was to estimate CO 2 flux from soil as affected by N applied to bermudagrass [ Cynodon dactylon (L.) Pers. C. transvaalensis Burtt Davy]. The study was initiated in March 2012 on 8‐yr‐old Tifway hybrid bermudagrass plots located at the Auburn University Turfgrass Research Unit on a Marvyn loamy (fine‐loamy, kaolinitic, thermic Typic Kanhapludult) sand soil. The experimental design was a randomized complete block with four N rates of 24, 49, 98, and 196 kg N ha −1 yr −1 that were replicated three times. Carbon dioxide flux was measured weekly for 95 wk using an automated soil CO 2 flux system (LiCor LI‐8100A, LICOR, Inc., Lincoln, NE). Soil temperature and moisture were also determined during CO 2 flux measurements. Results showed strong correlation between CO 2 flux and N rate ( r 2 = 0.99∗∗). Accumulated CO 2 flux increased by 35%, from 107 to 144 Mg ha −1 as N rate increased from 24 to 196 kg N ha −1 , respectively. Data suggest that a lower N application rate may be a better choice for mitigation of CO 2 emissions under bermudagrass management. Core Ideas Averaged daily fluxes of CO 2 were significantly ( r 2 = 0.99∗∗) correlated with N rate. Lower N application rate may be a better choice for mitigation of CO 2 emissions under bermudagrass management. Increasing soil temperature has increased CO 2 fluxes.