PARENT SESSION
Poster Session #40: Urban Ecology.
Thursday, August 9, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Carbon pool in urban and agricultural land use types in a Sonoran desert ecosystem.

Green, Douglas¹, Miyazawa, Shinichi¹, More, April¹, ¹

ABSTRACT- Alteration of carbon pools and changes to global C balance are major problems confronting the earth's ecosystem. As part of larger study to model the effects of urbanization on C pools, we quantified C pools in agricultural and suburban land use types. Our study site was located in the Phoenix, Arizona metropolitian area. We sampled soils and above ground biomass in single family residences, citrus groves, alfalfa, and cotton fields. Citrus groves had an above ground biomass of 29,898±3,240 kg ha^-1. Tree canopies accounted for 27% of the citrus biomass. We estimated total standing stock of a mature citrus grove as 13,603 kg ha-1. Total soil C in citrus groves was 0.44%. Cotton field has a peak standing biomass of 5689±545 kg ha^-1. Total C of cotton biomass averaged 42.3%. Total soil C in cotton fields was 0.49%. Alfalfa biomass averaged 1090±74.1 kg ha^-1 over the growing season sampled with a total C content of 41.2%. Total soil C in alfalfa fields was 0.93%. Standing biomass of turf areas in mesoscaped urban areas was 180±32.3 g m^-2 and 40.3% total C. Soils in mesoscaped areas averaged 1.11% total C. Total soil C is significantly higher in mesoscaped suburban than agricultural sites while above ground C is significantly lower in urban than agricultural sites.

KEY WORDS: urbanization, Arizona, carbon pools, soil