Comparison of soil physical properties under two different water table management regimes

Soil physical properties are important indicators of the potential for agricultural production. The objective of this research was to examine the difference in soil physical properties 9 yr after the initiation of two water table management (WTM) treatments in Wood County, Ohio. Water table management treatments included both unrestricted subsurface drainage year round (Drainage Treatment) and subirrigation during the crop-growing season to maintain the water table at 25 cm below the surface with unrestricted subsurface drainage the remainder of the year (Subirrigation Treatment). Soil samples were collected in eight plots, in six depth increments to a 1-m depth. Soil aggregation and related properties were significantly different in response to WTM treatments and soil depths. The subirrigated treatment had lower aggregate stability at 40 to 50 ern compared with the drainage treatment. The mean weight diameter (MWD) and geometric mean diameter (GMD) of aggregates in the subirrigated treatment were smaller than the drainage treatment at depths of 30 to 75 cm. Percentage of macroaggregates and aggregate ratios were generally lower in the subirrigation treatment than the drainage treatment. Subirrigated soils exhibited relatively lower bulk density with an associated increase in total porosity. The drainage treatment had greater penetration resistance from 30 to 45 cm on readings taken in Spring 2000. Subirrigated soils retained a greater volume of moisture at all matric potentials except -0.00015 and -1.5 MPa. The subirrigated soils are apparently not able to develop large, stable aggregates as seen in the continuously drained soil, perhaps because of the frequent water saturation followed by slaking of soil macroaggregates associated with subirrigation.