Abstract
Soils vary spatially in texture, structure, depth of horizons, and macropores, which can lead to a large variation in soil physical properties. In particular, saturated hydraulic conductivity (K
sat) and drainable porosity are critical properties required to model field hydrology in poorly drained lands. These soil-property values can be measured by several methods; however, larger scale, “field-effective” values may be needed in developing, calibrating, and validating models, such as DRAINMOD. In this investigation, field-effective soil-property values were estimated from water table and outflow measurements from a 3-year field experiment on poorly drained loblolly pine (
Pinus taeda L.) plantation watersheds in eastern North Carolina and tested against two additional estimation methods. Field estimates for K
sat were compared to estimates determined using the auger-hole method and estimates determined from soil cores by the constant-head method. The fieldeffective K
sat of the surface layer was estimated at 140 and 90 cm/hour for the unthinned and thinned condition, respectively. These values are greater than values obtained from soil cores and not different from values obtained from the auger-hole method which had mean conductivities of 100 and 80 cm/hour for unthinned condition, respectively. The thinned condition had K
sat values of 32 and 17 cm/hour based on soil cores and the auger-hole method, respectively. The differences between the field-based values and the constant-head method and auger-hole method may be a result of heterogeneity of soils or overestimations in the field-effective results.
Parent Publication
Citation
Grace, J. McFero, III; Skaggs, R.W. 2013. Determination of field-effective soil properties in the tidewater region of North Carolina. In: Guldin, James M., ed. 2013. Proceedings of the 15th biennial southern silvicultural research conference. e-Gen. Tech. Rep. SRS-GTR-175. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 411-419.