Joint Global Change Research Institute
Joint Global Change Research Institute: A Collaboration of the Pacific Northwest National Laboratory and the University of Maryland
Joint Global Change Research Institute: A Collaboration of the Pacific Northwest National Laboratory and the University of Maryland
PNNL
UMD
Simulating Long-term Crop Productivity and Soil Organic Carbon Dynamics with the EPIC Model Using Data from Arlington, WI
Authored by X He, R Cesar Izaurralde, M Vanotti, J Williams, Allison M Thomson
Abstract:

Soil C sequestration (SCS) has the potential to attenuate increasing atmospheric CO2 and mitigate greenhouse warming. Understanding of this potential and complex soil C process is aided by the use of simulation models. We evaluated the ability of the EPIC model to simulate corn (Zea mays L.) yields and soil organic C (SOC) at Arlington, WI during 1958-1991. Corn was grown continuously on a Typic Argiudoll with 3 N levels:  LTN1 (control), LTN2 (medium), and LTN3 (high). The LTN2 N rate started at 56 kg ha-1 (1958), increased to 92 kg ha-1 (1963), and reached 140 kg ha-1 (1973). The LTN3 N rate was maintained at twice the LTN2 level. In 1984, each plot was divided into 4 subplots receiving N at 0, 84, 168 and 252 kg ha-1. Five treatments were used for model evaluation. Percent errors of mean yield predictions during 1958-1983 decreased as N rate increased (LTN1 = -5.0%, LTN2 = 3.5%, and LTN3 = 1.0%). Percent errors of mean yield predictions during 1985-1991 were larger than during the first period. Simulated and observed mean yields during 1958-1991 were highly correlated (R2 = 0.961**). Simulated SOC agreed well with observed values with percent errors from -5.8% to 0.5% in 1984 and from -5.1% to 0.7% in 1990. EPIC captured the dynamics of SOC, SCS, and microbial biomass. Simulated net N mineralization rates were lower than those from lab incubations. Improvements in EPIC’s ability to predict annual variability of crop yields may lead to improved estimates of SCS.

He X, RC Izaurralde, M Vanotti, J Williams, AM Thomson. 2004. "Simulating Long-term Crop Productivity and Soil Organic Carbon Dynamics with the EPIC Model Using Data from Arlington, WI."