|HUYLER, A - Auburn University|
|CHAPPELKA, A - Auburn University|
|Prior, Stephen - Steve|
|SOMERS, G - Auburn University|
Submitted to: Urban Ecosystems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2014
Publication Date: 7/1/2014
Publication URL: http://handle.nal.usda.gov/10113/62406
Citation: Huyler, A., Chappelka, A.H., Prior, S.A., Somers, G.L. 2014. Influence of aboveground tree biomass, home age, and yard maintenance on soil carbon levels in residential yards. Urban Ecosystems. 17:787-805. doi:10.1007/s11252-014-0350-7.
Interpretive Summary: Metropolitan residential areas are expanding but little is known about urban soil carbon (C) pools in the southeastern US. The study was done in Auburn, AL to examine the relationship of soil C to tree aboveground biomass, home age, yard maintenance and soil texture. Soil texture had negligible influence on soil C. Turfgrass may be a stronger driver for soil C near the surface soil compared to aboveground tree biomass which had a stronger relationship at greater depths. Generally, home age influenced soil C increases at lower soil depths, but low frequency of annual fertilizer applications and a skewed distribution of irrigated yards to the younger home ages may be partially responsible for the lack of influence from fertilization and irrigation on soil C levels over home age. Directly examining the fate of soil C and lawn clippings over time and between strongly contrasting yard maintenance practices may provide more definitive answers to the effect of fertilization, irrigation, mulching or bagging on soil C levels. Overall, the legacy of the soil in residential yards needs to be a factor since the lack of knowledge on soil history hampers our ability to trace back and interpret the mechanisms underlying soil C sequestration.
Technical Abstract: In the past decade, research in urban soils has focused on the soil carbon (C) sequestration capacity in residential yards. We performed a case study to examine four potential drivers for soil C levels in residential yards. In 67 yards containing trees, we examined the relationship of soil C (kg m-2) to tree aboveground biomass, home age (3-87 years), yard maintenance (fertilization, irrigation, mulching or bagging lawn clippings) and soil texture (% clay, % sand, % silt), at three depths: 0-15 cm, 15-30 cm, and 30-50 cm. Six tree aboveground biomass data sets were developed: biomass, biomass*(1/distance from tree), biomass = 15 m from sample site, biomass = 10 m, biomass = 5 m, and biomass = 4 m. Biomass = 5 m and biomass = 4 m from the sample site had the greatest explanatory power for soil C in 30-50 cm depth (P =0.001, R2 = 0.28; P = 0.05 R2 = 0.39, respectively). The relationship between soil C and home age was positive at 0-15 cm (P = 0.0003, R2 = 0.19), sequestering 0.021 kg C m-2 yr-1, but remained constant in the two lower soil depths. Yard maintenance had no influence on soil C levels across home age. At 0-15 cm, soil C increased with % silt (P = 0.006, R2 = 0.12) but had no relationship with soil texture otherwise. Based on our findings, trees may have a stabilizing effect on soil C levels at 15-30 cm and 30-50 cm depths but minimal influence at 0-15 cm.