PARENT SESSION
Poster Session #1: Decomposition and Soil Respiration.
Monday, August 5. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Spatial patterns of soil respiration, temperature, and moisture in an experimental urban landscaped site.

Whitcomb, Sean^*,1, Stutz, Jean¹, Martin, Chris¹, ¹ Arizona State University, Tempe, AZ

ABSTRACT- Fine scale spatial patterns of soil CO₂ efflux, soil temperature, and gravimetric moisture were examined in an experimental urban landscaped site. Two 9.6 x 9.6 m human-managed permanent long-term monitoring plots were established in 1999 at the Desert Botanical Garden as part of the Central Arizona-Phoenix Long Term Ecological Research (CAP-LTER) project and planted with woody species commonly used in landscaping in Phoenix, Arizona. The plots were sampled in a regular grid pattern for soil CO₂ efflux rates, soil temperature, and gravimetric moisture in winter 2001. Unlike in many other studies, soil respiration rate, temperature, and moisture were not highly correlated. Semivariance analysis was performed to determine the degree of spatial autocorrelation of each of these variables in the plots. Significant spherical models were produced for CO₂ efflux, with a range of 4 to 5 m. Soil temperature and moisture were not autocorrelated at this scale of analysis. Patterns of variation for each variable were mapped using kriging. The kriged maps revealed high soil respiration rates near actively growing plants and very low rates in areas of bare soil and near winter-dormant plants. The results indicate that sampling of soil CO₂ efflux rates in landscaped areas of Phoenix must take spatial components of variation into account.

KEY WORDS: soil, respiration, spatial, urban