Preferential water flows in an ordinary chernozem of the Azov Plain

Preferential flows of gravitational water were studied with the use of modified grid lysimeters in an ordinary chernozem developed from loesslike loam on the slightly inclined Azov Plain. Within horizontal soil sections, the lysimetric water flow changed from high values to the complete absence at short (5–10 cm) distances. The funnel type of gravitational water flow concentration was noted. According to the character of changes in water infiltration during two consecutive cycles of soil watering, the zones with stable and altering (both increasing and decreasing) water flows were distinguished. No definite regularities of the changes in the concentration of the added label (chloride salts) in dependence on the intensity of the water flows and on the depth of the lysimeter installation were noted. Five days after the infiltration of considerable amounts of water (250 and 135 mm) into the soil monolith, the spatial variability of the concentration of the label was seen at distances of 5–15 cm.