|Sauer, Thomas - Tom|
Submitted to: World Agroforestry Congress
Publication Type: Abstract Only
Publication Acceptance Date: 7/2/2004
Publication Date: 7/2/2004
Citation: Defauw, S.L., Hays, P.D., Sauer, T.J., Brahana, J.V. 2004. Hydrodynamics of an experimental silvopastoral field in the ozark plateau of northwestern arkansas [abstract]. World Agroforestry Congress. p. 176.
Technical Abstract: An array of 53 piezometers, distributed over a 4.25 ha (10.5 acre) field in the Ozark Plateau of Northwestern Arkansas, USA, was monitored over two growing seasons (March-September 2002-2003). Shallow wells were augered to depth-of-refusal (installed 2000-2001), and presumably encompass the full range of the vadose zone in this karst terrain (with depths varying from 0.51 to 5.57 m beneath the land surface datum). Surface microtopography was reconstructed using a global positioning system (GPS), wells were geo-referenced, and a geographic information system (GIS) database established for hydrologic monitoring (N=21 events). The silvopastoral field (planted in from Fall 1999 to Fall 2000) consists of three nut crop zones, each approximately 1.22 ha (3 acres) in aerial extent; Dactylis glomerata var. Benchmark is the dominant forage cover. Overall, the oak zone (Quercus rubra) exhibits the least hydrodynamic variability. Sixteen out of 20 wells have mean water table levels of less than 1.00 m beneath the surface; subsurface fluctuations are low to moderate, with 14 well ranges varying from 0.02 to 0.70 m. Eastern Black Walnuts (Juglans nigra) occupy the most hydrologically-challenging tract. Thirteen out of 18 wells have mean water tables from 0.45 to 0.92 m below the surface. The range of subsurface fluctuations is the highest in the entire field, varying from 0.13 to 3.20 m. All fifteen wells emplaced in the pecan zone (Carya illinoensis) exhibit mean water table levels in excess of 1.20 m beneath the surface. Subsurface fluctuations for most wells in this zone are high, with hydrodynamic excursions varying from 1.71 to 3.12 m.