Validation of EPIC for two watersheds in southwest Iowa

被引:57
作者
Chung, SW
Gassman, PW [1 ]
Kramer, LA
Williams, JR
Gu, R
机构
[1] Iowa State Univ, Ctr Agr & Rural Dev, Dept Econ, Ames, IA 50011 USA
[2] Iowa State Univ, Dept Civil & Construct Engn, Ames, IA 50011 USA
[3] USDA ARS, Natl Soil Tilth Lab, Deep Loess Res Stn, Council Bluffs, IA 51503 USA
[4] Texas Agr Expt Stn, Blackland Res Ctr, Temple, TX 76502 USA
关键词
D O I
10.2134/jeq1999.00472425002800030030x
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The Erosion Productivity Impact Calculator (EPIC) model was validated using long-term data collected for two southwest Iowa watersheds in the Deep Loess Soil Region, which have been cropped in continuous corn (Zea mays L.) under two different tillage systems (conventional tillage vs. ridge-till). The annual hydrologic balance was calibrated for both watersheds during 1988 to 1994 by adjusting the runoff curve numbers and residue effects on soil evaporation. Model validation was performed for 1976 to 1987, using both summary statistics (means or medians) and parametric and nonparametric statistical tests. The errors between the 12-yr predicted and observed means or medians were <10% for nearly all of the hydrologic and environmental indicators, with the major exception of a nearly 44% overprediction of the N surface runoff loss for Watershed 2. The predicted N leaching rates, N losses in surface runoff, and sediment loss for the two watersheds clearly showed that EPIC was able to simulate the long-term impacts of tillage and residue cover on these processes. However, the results also revealed weaknesses in the model's ability to replicate year-to-year variability, with r(2) values generally <50% and relatively weak goodness-of-fit statistics for some processes. This was due in part to simulating the watersheds in a homogeneous manner, which ignored complexities such as slope variation. Overall, the results show that EPIC was able to replicate the long term relative differences between the two tillage systems and that the model is a useful tool for simulating different tillage systems in the region.
引用
收藏
页码:971 / 979
页数:9
相关论文
共 48 条
[11]   EPIC MODEL PARAMETERS FOR CEREAL, OILSEED, AND FORAGE CROPS IN THE NORTHERN GREAT-PLAINS REGION [J].
KINIRY, JR ;
MAJOR, DJ ;
IZAURRALDE, RC ;
WILLIAMS, JR ;
GASSMAN, PW ;
MORRISON, M ;
BERGENTINE, R ;
ZENTNER, RP .
CANADIAN JOURNAL OF PLANT SCIENCE, 1995, 75 (03) :679-688
[12]  
KRAMER LA, 1992, 922131 ASAE
[13]  
KRAMER LA, 1989, 892502 ASAE
[14]  
KRAMER LA, 1990, P 1990 CLUST C KANS
[15]  
KRAMER LA, 1989, 892511 ASE
[16]   COMPROMISE SOLUTION FOR ECONOMIC - ENVIRONMENTAL DECISIONS IN AGRICULTURE [J].
LAKSHMINARAYAN, PG ;
ATWOOD, JD ;
JOHNSON, SR ;
SPOSITO, VA .
JOURNAL OF ENVIRONMENTAL MANAGEMENT, 1991, 33 (01) :51-64
[17]   A metamodeling approach to evaluate agricultural policy impact on soil degradation in western Canada [J].
Lakshminarayan, PG ;
Gassman, PW ;
Bouzaher, A ;
Izaurralde, RC .
CANADIAN JOURNAL OF AGRICULTURAL ECONOMICS-REVUE CANADIENNE D ECONOMIE RURALE, 1996, 44 (03) :277-294
[18]  
LOAGUE K, 1991, Journal of Contaminant Hydrology, V7, P51, DOI 10.1016/0169-7722(91)90038-3
[19]  
MITCHELL G, 1996, EPIC USERS GUIDE DRA
[20]  
Mitchell PD, 1998, ADV SOIL S, P125