PARENT SESSION
Poster Session # 6: Urban Ecology.
Monday, August 4 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Changes in soil nutrient pools with urbanization in a Sonoran desert ecosystem.
Green, Douglas*,1, Miyazawa, Shinichi1, 1 Arizona State University East, Mesa, AZ, USA
ABSTRACT- Land use change and alterations to global carbon balance are important issues confronting the earth's ecosystem. As part of a study to model effects of urbanization on soils we quantified carbon nitrogen, available phosphorus, and electrical conductivity in desert and suburban land use types in the Phoenix, Arizona metropolitan area. We sampled soils of xeriscapes and mesiscapes (turf grass) in single-family residences ranging in age from 1 to 20 years old. Soils of Sonoran desert sites were sampled as controls. Soils of desert control sites averaged 0.59% C, significantly (P<0.05) lower than those of mesiscape sites (1.41%). Xeriscape soils were not significantly different from desert control soils. Total N and available P of desert controls were 0.048% and 8.90 g kg-1 respectively. Nitrogen and P levels of desert control soils were not significantly different from xeriscape soils (0.031% and 10.19 g kg-1). Mesiscape sites were significantly higher than either desert control or xeriscape soils in total N (0.96%) and available P (20.6 g kg-1). Electrical conductivity was significantly lower in desert control soils than either mesiscape or xeriscape soils. Regressions of total carbon against year since construction in mesiscapes and xeriscapes were not significant. Total nitrogen increased significantly (P < 0.05) with time since construction in mesiscape and xeriscape sites. Available phosphorus did not change significantly with time in either mesiscape or xeriscape sites. Our results indicate that while mesiscape sites tend to be significantly higher in total C, N, and available P, with the exception of total N change of measures soil variables may occur on a temporal scale exceeding the one measured in this study.
Key words: urbanization, desert, carbon, soils