BOUNDARY LOCATION FROM TEXTURE, SOIL-MOISTURE, AND INFILTRATION DATA

The objective was to ascertain how well different soil physical properties or parameters could be used to identify boundary locations along a soil transect. A transect was established with 91 positions, 1 m apart. The infiltration rate was measured along the transect with small (0. 3-m diam) and large (1. 0-m diam) infiltration rings. Thereafter, 91 soil samples were taken at a depth of 0. 3 m for texture analysis. Also, 91 neutron access tubes and tensiometers were installed in two parallel lines 0. 3 m apart. Soil-water content was measured 16 times at the 0. 3-m depth before and after flooding the transect. Soil-water tension was measured 13 times after flooding. The moving split window technique was used as a numerical procedure for boundary location. Boundaries detected - based on soil texture, water content, and water tension data - nearly coincided. Window width had little effect on detection of boundaries. The moving split window technique appears to be a useful tool for establishing boundaries along transects, based on water content and tension data, or in combination with soil texture data.