Influence of tillage and plant residue management on respiration of a Florida Everglades Histosol Russ W. Gesch a, * , Don C. Reicosky a , Robert A. Gilbert b , Dolen R. Morris c a USDA-ARS, North Central Soil Conservation Research Laboratory, 803 Iowa Ave., Morris, MN 56267, USA b Everglades Research and Education Center, University of Florida, Belle Glade, FL 33430, USA c USDA-ARS, Sugarcane Field Station, Canal Point, FL 33438, USA Received 7 June 2005; received in revised form 20 January 2006; accepted 22 February 2006 Abstract Subsidence of drained, high organic matter Histosols in the Everglades Agricultural Area (EAA) is a concern for the sustainability of crop production in southern Florida. Histosol subsidence is primarily due to oxidation of organic matter by aerobic microorganisms, but far less is known about the influence of agricultural practices. The use of shallow tillage, as opposed to deep tillage, combined with proper plant residue management, may help to reduce the present rate of subsidence and soil CO 2 emissions. The present study was conducted on a Lauderhill soil (euic, hyperthermic, Lithic Haplosaprist) previously cropped in sugarcane (Saccharum spp.). The objectives were to (1) determine the effects of tillage depth on short-term CO 2 losses in a herbicide-killed weedy residue covered field and another field kept fallow without residue cover, and (2) compare soil respiration measurements made with two different dynamic closed-system portable chamber techniques. Four tillage practices common to the EAA were used to produce soil disturbance ranging in depth from approximately 20 to 300 mm. These practices included switch plowing, disk harrowing, and single and multiple tine cultivation. Twenty-four hours after tillage, cumulative CO 2 loss from the deepest tillage treatment (switch plow; 300 mm deep) was as much as 33 times greater than that from the no-till (control) treatment. Cumulative CO 2 loss following intermediate tillage (disk harrow; 78–145 mm deep) was as much as 2.3-fold greater than the no-till treatment, but shallower tillage (tine cultivation; 20–41 mm deep) was generally not different. Short-term tillage-induced CO 2 loss was primarily related to soil moisture content and soil porosity. Soil respiration measurements made with the two chamber techniques agreed well with each other except for the deepest tillage treatment, where the larger chamber measured CO 2 flux that was approximately 10 times greater than for the smaller chamber. Results indicate that minimum or no-tillage may reduce short- term tillage-induced CO 2 emissions on organic soils, thus minimizing soil subsidence. # 2006 Published by Elsevier B.V. Keywords: Histosol; Soil respiration; Tillage; Residue management 1. Introduction The Everglades Agricultural Area (EAA), located in southern Florida, USA, is an area of the Everglades watershed that was drained in the early 1900s for agricultural production (Stephens and Johnson, 1951; Shih et al., 1998). Sugarcane (Saccharum spp.) is the most valued crop in the EAA and is grown on approximately 180,000 ha annually (Glaz and Vonder- well, 2004). Additionally, the EAA produces a large portion of the nation’s winter vegetable crops (Ingeb- ritsen et al., 1999). The soils in the EAA are Histosols with organic matter content as high as 80–90% (Snyder et al., 1978). Since the draining and establishment of the EAA, soil subsidence has become an ongoing problem. www.elsevier.com/locate/still Soil & Tillage Research 92 (2007) 156–166 * Corresponding author. Tel.: +1 320 589 3411x132; fax: +1 320 589 3787. E-mail address: gesch@morris.ars.usda.gov (R.W. Gesch). 0167-1987/$ – see front matter # 2006 Published by Elsevier B.V. doi:10.1016/j.still.2006.02.004