Cotton producers can maximize profits and yield by using soil electrical conductivity (EC) measurements to help manage fields.  Using soil EC maps, producers can map the soil variability of cotton fields.  The project objectives are to 1) create a map of cotton lint-quality zones using soil electrical conductivity (EC) measurements; 2) understand the relationship between soil properties and higher quality lint; and 3) develop 10 m resolution return-on-investment maps based on soil EC, cotton yield, and cotton quality. The selected site was Texas A&M University’s IMPACT center which is located nine miles west of College Station, TX in the Brazos River floodplain.  In the 2006 and 2007 growing season, 24 measurement locations were selected in a dryland and irrigated cotton field, 12 locations in each field. The sites were selected using a map of soil EC, three EC categories and four replications. At each location soil texture, soil moisture (weekly), and lint quality (AFIS and HVI) and quantity were measured. The measured soil textures ranged from sandy loam to clay.  In 2006, lint yield in the irrigated field was higher than dryland yield.  In the irrigated field the middle EC category had the highest yield, while in the dryland field the highest EC category had the highest yield.  In the irrigated field the lowest EC category had significantly poorer lint quality, while in the dryland field the highest EC category had significantly better lint quality (p-value 0.05).  The EC map responded to different soil textures, exhibited differences in water holding capacities, and indicated locations in each field with significantly different lint yield and quality, making EC maps a useful precision harvesting tool. Results from 2007 will be presented as well.