../images/WERU1.jpg (520546 bytes)

Wind Erosion:
An International Symposium/Workshop

wpe1.jpg (23363 bytes)   ars.jpg (19015 bytes)   weru.gif (1894 bytes)  ander3.gif (9862 bytes)


bar.bmp (45462 bytes)

Participant Information
Photograph of Participants
Breakout Sessions
Tour Reports
WERU History

bar.bmp (45462 bytes)


Field Evaluation of Energy Balance Simulation of Surface Soil Temperatures

R. M. Aiken, D. C. Nielsen, M. F. Vigil, and L. R. Ahuja


       Surface crop residues help stabilize soils by reducing soil water loss, reducing the erosive force of wind and shielding the soil from saltating particles. Our objectives were to quantify seasonal changes in the geometry of crop residues, residue effects on soil water recharge efficiency, and to evaluate the predictive accuracy of PENFLUX, a simplified soil-residue energy boundary condition module, that is compatible with the USDA-ARS Root Zone Water Quality Model. We quantified soil and residue micro-climatic conditions and residue geometry following the 1995 harvest of wheat (Triticum aestivum), millet (Panicum miliaceum), corn (Zea mays) , and sunflower (Helianthus annuus) under no till management at the ARS Central Great Plains Research Station located 7 km E of Akron, CO (40o N, 103o W, 1400 m elev.); stubble mulch tillage of wheat was included for comparison. We evaluated net irradiance and soil temperature (5 mm soil depth) calculated from a Penman-type energy balance module, solving for surface residue and soil temperatures. Wheat_NT increased the fraction of early spring precipitation retained in the soil profile, attributed, in part to reduced turbulent mixing of near-surface winds. The number of standing stems decreased linearly over time. Loss of soil cover resulted from residue decomposition during warm and wet spring conditions, and was likely accelerated by mechanical action of wind during cold winter conditions. Non-calibrated simulation of surface energy balance demonstrated high precision with persistent bias for net radiation (R2 > 0.99) and surface temperature (R2 > 0.86). Simulated evaporation was greatest for systems with lowest soil cover--sunflower_NT and wheat_SM. Quantitative knowledge of these processes can support residue management decisions for conservation of soil and water.