Intensive management modifies soil CO₂ efflux in 6-year-old Pinus taeda L. stands

Abstract

Intensive forestry may reduce net CO₂ emission into atmosphere by storing carbon in living biomass, dead organic matter and soil, and durable wood products. Because quantification of belowground carbon dynamics is important for reliable estimation of the carbon sequestered by intensively managed plantations, we examined soil CO₂ efflux (S_CO2) in a 6-year-old loblolly pine (Pinus taeda L.) plantation in response to weed control (W), weed control plus irrigation (WI), weed control plus irrigation and fertigation (addition of fertilizer to the irrigation water) (WIF), and weed control plus irrigation, fertigation and pest control (WIFP) since plantation establishment. Average S_CO2 ranged from 1.27 to 5.59 µmol m^-2s^-1, and linear models indicated that soil temperature explained up to 56% of the variation in S_CO2. Plot position explained an additional 2–11% of the variation in S_CO2. Soil moisture was only weakly correlated with S_CO2 in the W treatment, and S_CO2 was not significantly correlated to fine root mass. Predicted carbon loss from forest floor respiration ranged between 778 and 966 g C m^-2 year ^-1 and was 20% lower in the WIF treatment relative to the W treatment. Annual soil carbon loss through soil respiration declined linearly with increasing carbon content in total root biomass (tap + coarse + fine) at age 6.

Keywords

loblolly pine, fertilization, carbon sequestration, soil respiration

Citation

Samuelson, Lisa J.; Johnsen, Kurt; Stokes, Tom; Lu, Weinlang. 2004. Intensive management modifies soil CO₂ efflux in 6-year-old Pinus taeda L. stands. Forest Ecology and Management 200 (2004) 335–345