MAPPING SHALLOW UNDERGROUND FEATURES THAT INFLUENCE SITE-SPECIFIC AGRICULTURAL PRODUCTION

Modern agricultural production practices are rapidly evolving in the U nited States of America (USA). These new production practices present significant applications for nonintrusive subsurface imaging. One such imaging technology is GPR, and it is now being incorporated within si te-specific agriculture in the detection of soil horizons, perched wat er (episaturation), fragipans, hydrological preferential flow paths, a nd soil compaction. These features traditionally have been mapped by s oil scientists using intrusive measurements (e.g., soil augers, soil p its, coring tools). Rather than developing a tool for soil mapping, ou r studies are targeting the identification, dimensioning, and position of subsurface features that directly influence agricultural productiv ity. It is foreseen that this information will allow for an increase i n agricultural efficiency through infield machinery automation, and it will also greatly enhance development of highly efficient crop produc tion strategies. The field sensing methodologies that we have develope d using existing geophysical technologies are highly dependent upon bo th the soil and site characteristics due to seasonal variations. The G PR applications presented herein were conducted primarily in a region of loess soil that extends east of the Mississippi River into western Tennessee. GPR studies were also conducted in central Tennessee on the Cumberland Plateau within a region of shallow, sandy loam soils. Addi tional studies were conducted on the karst area of central Kentucky. A lthough targeting site-specific agriculture, our results and procedure s may benefit the traditional users of GPR technology. We suggest that large-scale agricultural applications of the technology would be enha nced by integrating global positioning (GPS) technology in future hard ware and software products. (C) 1998 Elsevier Science B.V. All rights reserved.