Spectrophotometric Determination of Soil Water Content

Abstract
The absorbance at 1.94µ by a soil‐methanol extract was used for measuring the soil water contents of three different textured soils. A linear relation between absorbance and soil water content was adequate for moisture determinations ranging from air dry to the moisture equivalent. For Quincy loamy sand and Barnes loam soils, calibration based only on laboratory standards was sufficient. For Houston Black clay, calibration against oven‐dry samples was necessary. Determination time was approximately 1 hour.