Modeling Carbon Sequestration in Home Lawns

Abstract

Soil organic carbon (SOC) sequestration and the impact of carbon (C) cycling in urban soils are themes of increasing interest. A model was developed to investigate the potential of C sequestration in home lawns. The model contrasted gross C sequestered versus the hidden C costs (HCC) associated with typical lawn maintenance practices. The potential of SOC sequestration for U.S. home lawns was determined from SOC sequestration rates of turfgrass and grasslands. Net SOC sequestration in lawn soils was estimated using a simple mass balance model derived from typical homeowner lawn maintenance practices. The average SOC sequestration rate for U.S. lawns was 46.0 to 127.1 g C/m2/year. Additional C sequestration can result from biomass gains attributable to fertilizer and irrigation management. Hidden C costs are the amount of energy expended by typical lawn management practices in grams of carbon equivalents (CE)/m2/year and include practices including mowing, irrigating, fertilizing, and using pesticides. The net SOC sequestration rate was assessed by subtracting the HCC from gross SOC sequestration rate. Lawn maintenance practices ranged from low to high management. Low management with minimal input (MI) included mowing only, a net SOC sequestration rate of 25.4 to 114.2 g C/m2/year. The rate of SOC sequestration for do-it-yourself (DIY) management by homeowners was 80.6 to 183.0 g C/m2/year. High management, based on university and industry-standard best management recommendation practices (BMPs), had a net SOC sequestration rate of 51.7 to 204.3 g C/m2/year. Lawns can be a net sink for atmospheric CO2 under all three evaluated levels of management practices with a national technical potential ranging from 25.4 to 204.3 g C/m2/year.