The utilization of remote sensing in soil survey

This investigation was initiated to study the utilization of remote sensing in soil survey. It was conducted at the University of Tennessee under the title of Project Themis which is an interdisciplinary investigation of the utilization of remote sensing techniques in environmental systems studies. There is an ever increasing demand for soil surveys for agricultural as well as nonagricultural uses, and new tools such as remote sensing must be used to increase the accuracy and efficiency of such surveys. Research data for this study were in the form of aerial photographic and nonphotographic imagery taken from a DC 3 aircraft. Photographic sensors included four 70 mm Hasselblad Cameras which operated simultaneously and produced an image of exactly the same area. The films used were Kodak Ektachrome Aero Infrared (8443) , Kodak Aerographic Infrared (5424), Kodak Plus X Aero (8401), and Kodak Ektachrome MS Aero Color (2448). The nonphotographic sensor used was a Daedalus infrared line scanner using the Mercury Cadmium detector which was sensitive in the 8-14 micron range. Several sites in Tennessee were selected for this study, and data collecting flights were flown in 1968, 1969, and 1970. Various altitudes and filmfilter combinations were used to produce variations in the imagery obtained. Imagery analysis was accomplished by the delineation of soil boundaries using two methods. One was visual, and the other was mechanical using a scanning microdensitometer and a computer. Soil maps and onsite investigations were used to determine if the soil boundaries delineated were accurate and correct. Soil and plant conditions used to delineate soil series were identified by photographic and nonphotographic imagery. Color, moisture, and temperature were used as indicators for series delineations in bare soil. Differences in vegetative reflectance and types of vegetation were also used to indicate soil conditions related to series differences. The results of this study indicated remote sensing techniques can be used under limited conditions in soil survey.