Abstract

Soil-moisture change was monitored using polarized visible light recorded on panchromatic film, and visible and infrared reflectance recorded on false-color film. Photographic records of a draining sandy loam on a sloping apparatus in the laboratory and a peat soil in the field, were backed by detailed soil-moisture measurements and laboratory spectrophotometric recordings. There was difficulty in obtaining real-time in situ measurements of soil surface moisture of comparable sensitivity to photographic temporal data. False-color infrared film provided qualitative spatial description of soil-moisture state, especially at high water contents in the peat and low water contents in the sandy loam. This film was unable to accurately record a changing soil-moisture state. Polarized reflectance successfully recorded a fairly wide, but not unlimited, range of changing soil-moisture conditions, thus suggesting its limited suitability as a monitoring technique.