Modelling stover and grain yields, and subsurface artificial drainagefrom long-term corn rotations using APSIM

Abstract

The Agricultural Production Systems Simulator (APSIM) is a key tool to identify agricultural managementpractices seeking to simultaneously optimize agronomic productivity and input use efficiencies. The aimsof this study were to validate APSIM for prediction of stover and grain yield of corn in four contrasting soilswith varied N fertilizer applications (156–269 kg N ha−1) and to predict timing and volume from artificialsubsurface drains in continuous corn and corn-soybean rotations in a silty clay loam soil at West Lafayette,IN. The APSIM validation was carried-out using a long-term dataset of corn stover and grain yields fromthe North Central Region of IN. The CCC (Concordance Correlation Coefficient) and SB (Simulation Bias)were used to statistically evaluate the model performance. The CCC integrates precision through Pearson’scorrelation coefficient and accuracy by bias, and SB indicates the bias of the simulation from the mea-surement. The model demonstrated very good (CCC = 0.96; SB = 0%) and satisfactory (CCC = 0.85; SB = 2%)ability to simulate stover and grain yield, respectively. Grain yield was better predicted in continuouscorn (CCC = 0.73–0.91; SB = 19–21%) than in corn-soybean rotations (CCC = 0.56–0.63; SB = 17–18%), whilestover yield was well predicted in both crop rotations (CCC = 0.85–0.98; SB = 1–17%). The model demon-strated acceptable ability to simulate annual subsurface drainage in both rotations (CCC = 0.63–0.75;SB = 2–37%) with accuracy being lower in the continuous corn system than in corn-soybean rotation sys-tem (CCC = 0.61-0.63; SB = 9–12%). Daily subsurface drainage events were well predicted by APSIM duringlate spring and summer when crop water use was high, but under-predicted during fall, winter and earlyspring when evapotranspiration was low. Occasional flow events occurring in summer when soils werenot saturated were not predicted by APSIM and may represent preferential flow paths currently not rep-resented in the model. APSIM is a promising tool for simulating yield and water losses for corn-basedcropping systems in north central Indiana US.