Soil microbiological properties, soil nitrate and organic carbon were examined in a long-tern tillage management experiment. Minimum tillage (MT) was compared with conventional (CT) and moldboard (MB) plow systems in a continuous cotton cropping system. The dryland study was conducted on an Orelia scl (Typic Ochraqualf) using short-season cotton cultivars. Soil was sampled at 0-1, 1-2, 2-3, and 3-6 inch depths.

Soil nitrate, moisture, organic carbon, and heterotrophic bacteria (HB) varied with tillage treatment at the 3-6 inch depth. Conventionally tilled soil had greater HB and soil organic carbon at the 3-6 inch depth than did the MT soil treatment There were no significant differences with HB, actinomycetes, nitrate, and carbon with tillage treatment in the surface greater in the CT and MB treatments at the 1-2 inch depth than in the MT treatment. Soil organic carbon and HB were positively correlated. Soil moisture varied with tillage treatment and possibly limited microbial growth in the surface three inches.