Black oat (Avena strigosa Schreb.) is the predominate cover crop on millions of acres of conservation - tilled soybean [Glycine max (L.) Merr.] in southern Brazil due in part to its weed suppressive capabilities. We initiated a field study in 1995 on a Dothan fsl (fine-loamy, siliceous, thermic Plinthic Paleudult) in southeastern AL to determine the suitability of black oat as a cover crop for conservation-tilled cotton (Gossypium hirsutum L.) using the Brazilian system of managing cover crops. The site had been in conservation tillage for the previous 8 yr and had a high population of Palmer Amaranth (Amaranthus palmeri S. Watts.). Cotton was grown in a strip-plot design of four replications. Horizontal plots were winter covers of black oat, rye (Secale cereale L.), wheat (Triticum aestivum L.) or fallow. The cover crops were terminated with an application of glyphosate (1.0 lb a.i./A) 3 wks prior to planting DPL 5690 cotton in early May each year. Within 3 days following glyphosate application, the covers were rolled with a modified stalk chopper to lay all residue flat on the soil surface. Vertical plots were herbicide input levels: none, low, or high. The low herbicide input level consisted of a preemergence application of pendimethalin (1.0 lb a.i./A) + fluometuron (1.5 lb a.i/A). For the high input level, additional applications of fluometuron (1.0 lb a.i./A) + DSMA (1.5 lb a.i./A) early post-direct and lactofen (0.2 lb a.i./A) + cyanazine (0.75 lb a.i./A) late post-direct were made. In 1995, because the site has a well developed hardpan, the cotton was in-row subsoiled with a narrow parabolic subsoiler equipped with pneumatic tires to close the subsoil channel with minimal disturbance of the residue. In 1996, the area was paratilled 2 wks prior to planting.