Monday, November 2, 2009: 10:00 AM
Convention Center, Room 315, Third Floor
Soil organic carbon (SOC) sequestration and the impact of carbon cycling in urban soils are themes of increasing interest. There are 80 million
U.S. single family detached homes comprising of 6.4 million ha of lawns with an average size lawn of 0.08 ha. The potential of SOC sequestration for U.S. home lawns is determined from the SOC rates of turfgrass and grasslands. Net SOC sequestration in lawn soils is estimated using a mathematical model derived from typical homeowner lawn maintenance practices. The average SOC accumulation rate for U.S. lawns is 80.0 kg C lawn-1 yr-1. Additional C accumulation results from fertilizer and irrigation management. Hidden C costs (HCC) of typical lawn management practices include mowing, irrigating, fertilizing, and pesticide application. The net SOC sequestration is assessed by subtracting the HCC from gross SOC sequestered. Lawn maintenance practices range from low to high management. Low management or minimal input (MI) includes mowing only, with a net SOC sequestration rate of 63.5 – 69.7 kg C lawn-1 yr-1. Do-It-Yourself (DIY) management by homeowners is 106.9 – 122.4 kg C lawn-1 yr-1. High management is based on university and industry-standard best management recommendation practices (BMPs) and has a net SOC sequestration rate of 85.3 – 142.9 kg C lawn-1 yr-1. Results support the conclusion that lawns are a positive net sink for atmospheric CO2 under all evaluated levels of management practices with a national technical potential ranging from 63.5 – 142.9 kg C lawn-1 yr-1.