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United States Department of Agriculture

Agricultural Research Service


item Desmond, Eric
item Ward, Andy
item Fausey, Norman - Norm
item Workman, Stephen

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: There are currently many social and economic pressures on farming, especially related to the effect of farming on the environment. Farmers and others need good tools to help them evaluate the effects of management changes on productivity, profitability, and environmental impact. These tools are called decision aids and they depend on models that mimic the real world situation. How well these models represent the real system the farmer manages, determines the confidence the farmer and others (regulators, policy makers, bankers) have in the output or advice given by the decision aids. A new model for determining optimum water management systems for the humid region of the U.S. called ADAPT was found to predict the water table depth and movement similarly to three other models, DRAINMOD, SWATREN, and PREFLOW. This is important because ADAPT also provides chemical transport information associated with the water movement while the other models do not give this information. Therefore, farmers or others who use ADAPT to decide how best to manage the water in the soil can also evaluate the effect of the water management on the quality of water moving from their fields to streams or ground water.

Technical Abstract: The Agricultural Drainage And Pesticide Transport (ADAPT) model was compared to the water management simulation models DRAINMOD, SWATREN, and PREFLO. SWATREN and PREFLO are one-dimensional finite-difference models that function on daily and hourly time steps, respectively. ADAPT and DRAINMOD are one-dimensional mass balance models with daily and hourly time steps, respectively. ADAPT, an extension of the computer model GLEAMS, also provides chemical transport information. All four models were tested against field data from Aurora, North Carolina. The observed data were collected from an experiment with subsurface drain spacing treatments of 7.5 m, 15 m, and 30 m. Also, a sensitivity analysis with several key input parameters was performed with the ADAPT model. For the five-year period ADAPT, DRAINMOD, SWATREN, and PREFLO had standard errors of estimated water table means of 0.19, 0.19, 0.19, and 0.18 m, respectively, and absolute deviations of 0.15, 0.14, 0.14, and 0.14 m, respectively. The results show good agreement among these models for this experimental site, any of which may be used to adequately simulate the water table behavior over time.

Last Modified: 10/17/2017
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