Definitions

1. The claypan is a slightly concave surface approximately 100m across.
2. The claypan is a consolidation of dense clay beneath the upper layers of the soil.
3. The claypan is a naturally-occurring argillic soil horizon that limits percolation to groundwater.

Ec

1. In our work on claypan soils, we have found EC to be strongly correlated with the depth of topsoil above the claypan horizon. (Web site)
2. Our results suggest that sensor-based EC a can be a quick and economical way of estimating some claypan soil quality measurements.

Mm

1. First, the depth to claypan varies between 130 and 370 mm with an average of 250 mm ( Jamison and Peters, 1967).
2. For instance, the K eff for the surface soil of the Mexico claypan soil is 0.34 mm h -1 ( Nearing et al., 1996).

Values

1. Conversely, the claypan was nearer the surface for eroded shoulder and side-slope positions, giving higher EC^sub a^ values.
2. Because of their hydrologic attributes, claypan soils probably have quite different effective K sat values with depth from other Alfisols.

Depth

1. Depth to the claypan was determined by obtaining 20-mm diam.
2. We attribute improved correlation in the deeper depth to the fact that the claypan horizon was often included in this sampling depth.
3. UNDULATING OR SPOTTY PLANT GROWTH ON SODIC SOILS Both claypan depth and root restriction vary considerably within a few feet.

Claypan

1. The CEC for claypan soil is mostly generated from claysized particles.
2. Figure 1 shows the K sat measured on selected Missouri claypan soils.
3. A claypan is commonly hard when dry and plastic or stiff when wet. (Web site)
4. Crop management effects on water infiltration for claypan soils.
5. The subsoil claypan horizons are silty clay loam, silty clay, or clay, and commonly contain as much as 50 to 65% clay.

Cores

1. Cores collected at or below the claypan, were wet for 7 d.
2. Measurement of K sat on cores without bentonite had higher conductivities even for samples within the claypan with high montmorillonitic clay content.

Runoff

1. Blanco-Canqui, H. 1995. Saturate hydraulic conductivity and runoff for a Mexico claypan soil. (Web site)
2. A field trial was conducted on a Mexico silt loam claypan soil in north-central Missouri for 3 years (2000-2002). (Web site)
3. A study of claypan hydrology suggests that runoff rates may be equal to rainfall under saturated conditions ( Saxton and Whitaker, 1970).

Soil Properties

1. Soil properties were affected by management only in the surface 0 to 10 cm, and were controlled by the depth of the claypan horizon.
2. Relationship of apparent soil electrical conductivity to claypan soil properties.
3. For these claypan soils, the type of relationship a soil property may have with yield is highly dependent on seasonal precipitation.

Macropores

1. This was attributed to the variations in soil depth to claypan, macropore presence, and methodology.
2. Downward flow through the claypan was obtained by subtracting outflow from the inflow.
3. Secondly, claypan soils often have abundant macropores ( Jordan et al., 1997).

Argillic Horizon

1. Because of the argillic horizon, claypan soils may perch water and create lateral flow.
2. Three in situ monoliths 250 mm wide by 500 mm long by 230 mm deep (the depth to claypan) were constructed.
3. Results suggest that the argillic horizons were a barrier directing the vertical flow horizontally above the claypan as lateral flow.
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