Carbon Sequestration in Zoysiagrass Turf under Different Irrigation and Fertilization Management Regimes

Abstract

Core Ideas: Further research is required to evaluate and develop management practices that may sequester C in turfgrass soils. Hidden C costs, which are energy-based inputs from turf maintenance, should be factored into soil C sequestration calculations. A higher-input management regime in turf will not increase net C sequestration compared with a low management input regime. Zoysiagrass golf course fairway turf had an average gross C sequestration rate of 1.01 Mg C ha–1 yr–1. Carbon dioxide (CO2) is an important greenhouse gas (GHG) implicated in climate change. Turfgrass covers an estimated 12.8 to 20 million ha in the United States and has the capacity to sequester or emit significant amounts of CO2 from/into the atmosphere. Our objective was to evaluate irrigation and N fertilization management practices that may increase sequestration of atmospheric CO2 in turf soils. The rate of change in soil organic carbon (SOC) at 0 to 30 cm was investigated under two management regimes in ‘Meyer’ zoysiagrass (Zoysia japonica Steud.). A high management input (HMI) (urea + medium irrigation) and low management input regime (LMI) (unfertilized [no N fertilizer] + low irrigation) were implemented. Hidden carbon costs (HCC) of maintenance practices and nitrous oxide emissions (another GHG) were estimated to account for energy expended in Mg of carbon equivalents (CE) ha–1 yr–1. Prior to subtracting HCC, average gross C sequestration rates were not statistically different at 1.046 and 0.976 Mg C ha–1 yr–1 in HMI and LMI, respectively. Once total estimated HCC was included, the average net sequestration rate was 0.412 and 0.616 Mg C ha–1 yr–1 in HMI and LMI, respectively, with no statistical differences. Results indicate that under the conditions of this study, a higher-input management regime will not increase net C sequestration compared with a low management input regime. Further research is required over additional turfgrass species and management regimes to develop management practices that increase C sequestration.