The facilitation of site-specific management in a crop field requires that the variability of yield-limiting characteristics be spatially quantified.  One method of managing variability is through the use of productivity level management zones.   These zones are homogeneous areas of crop field that have similar yield-limiting factors that can be managed uniformly.  Successful techniques for delineation of management zones have been developed for irrigated, conventionally tilled land that allow for color and tone differences in bare soil imagery to be used in characterizing variability related to yield potential.  Crop residue present in no-till fields is considered noise in this process.  The objective of this study is to determine whether delineation of productivity level management zones for no-till dryland crop fields in eastern Colorado can be accomplished with the use of georeferenced shallow soil electrical conductivity (EC) measurements and terrain attributes such as elevation, slope, and aspect.  This information can be analyzed through geostatistical methods such as interpolation and clustering to objectively delineate productivity level management zones for site-specific or variable rate management.  Soil EC has been correlated to many soil properties that affect productivity and has been illustrated in prior studies to characterize soil spatial variability.  Geographically referenced yield data will be used to validate delineated management zones.   Data collection of three no-till dryland fields in eastern Colorado will take place during the summer of 2006.  Variability will be quantified and analyzed, and results will be presented at the 2006 Annual ASA-CSSA-SSSA meetings.