Variations in near-saturated hydraulic conductivity of arable mineral topsoils in south-western and central-eastern Finland

Abstract

Soil hydraulic properties play an important role in determining the level of crop productivity and the extent of environmental loading. Consequently, measurement of near-saturated soil hydraulic conductivity (K(h)) by tension infiltrometer (TI) is an interesting technique. To provide reference values for near-saturated K(h) in arable mineral topsoils of Finland and to investigate variability in these values caused by tillage, antecedent soil moisture content and earthworm burrows, field measurements were conducted in south-western and central-eastern Finland using the TI technique, at supply pressure head –6, –3, and –1 cm. The range of near-saturated K(h) values obtained was 0.02–12.6 mm h-1 at –6 cm, 0.30–85.9 mm h-1 at –3 cm, and 2.55–250 mm h-1 at –1 cm. At –6 cm pressure head, clay soils tended to show lower values than coarser-structured soils, but the order was reversed at –1 cm. The spatial variation in near-saturated K(h) was moderate and was exceeded by the temporal variation.