Fig. 1. Soil CO₂ efflux in conventional tillage (CT), mulch till (MT), no till (NT), and bare fallow (BF) cotton production systems during a growing season and amount of rain fall (RF) + irrigation water (IW) received 1 wk before the day of CO₂ efflux measurement, Belle Mina, AL, 2003, 2004, and 2006 (vertical bars = SE).