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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCED SYSTEM MODELS AND DECISION SUPPORT TOOLS TO OPTIMIZE WATER LIMITED AGRICULTURE Title: Modeling of full and limited irrigation scenarios for corn in a semiarid environment

Authors
item Dejonge, Kendall -
item Andales, Allan -
item Ascough, James
item Hansen, Neil -

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 24, 2011
Publication Date: April 21, 2011
Citation: DeJonge, K.C., Andales, A.A., Ascough II, J.C., Hansen, N.C. 2011. Modeling of full and limited irrigation scenarios for corn in a semiarid environment. Transactions of the ASABE. 54(2):481-492.

Interpretive Summary: The objective of this study was to calibrate and evaluate the CERES-Maize v4.0 crop growth model for full and limited irrigation conditions and determine the model's ability to differentiate irrigation treatments in terms of ET, crop growth, and yield. Field experiments of corn were performed near Fort Collins, Colorado between 2006 and 2008, where four replicates each of full and limited irrigation treatments were evaluated. Observations of soil profile water content, leaf area index, leaf number, and grain yield were used to calibrate and evaluate the model. Additionally, ET and water use efficiency (WUE) were calculated based on field water balance and compared to model estimates. Over the three years evaluated, the model agreed with observed trends in anthesis date, seasonal cumulative ET, leaf count, leaf area index, and yield. Simulation of late-season leaf area index in limited irrigation was underestimated, indicating model overestimation of water stress. Simulated cumulative ET trended similar to observed values, although the model showed some tendency to underpredict for full irrigation and overpredict for limited irrigation. Limited irrigation observations showed a significant increase in WUE over full irrigation in two of the three years; however, the model was unable to replicate these results due to underestimation of ET differences between treatments. While CERES-Maize generally agreed with observed trends for full and limited irrigation scenarios, simulation results show that the model could benefit from a more robust water stress algorithm that can accurately reproduce plant responses such as those observed in this study.

Technical Abstract: Population growth in urbanizing areas such as the Front Range of Colorado has led to increased pressure to transfer water from agriculture to municipalities. In some cases, farmers may remain agriculturally productive while practicing “limited or deficit irrigation,” where substantial yields may be obtained with reduced water applications during the non-water sensitive growth stages. Savings in crop evapotranspiration (ET) could then be leased to municipalities or other entities as desired. The objective of this study was to calibrate and evaluate the CERES-Maize v4.0 crop growth model for full and limited irrigation conditions and determine the model's ability to differentiate irrigation treatments in terms of ET, crop growth, and yield. Field experiments of corn were performed near Fort Collins, Colorado between 2006 and 2008, where four replicates each of full and limited irrigation treatments were evaluated. Observations of soil profile water content, leaf area index, leaf number, and grain yield were used to calibrate and evaluate the model. Additionally, ET and water use efficiency (WUE) were calculated based on field water balance and compared to model estimates. Over the three years evaluated, the model agreed with observed trends in anthesis date, seasonal cumulative ET (Nash-Sutcliffe model efficiency index ENS = 0.966 for full irrigation and 0.835 for limited irrigation), leaf count in 2007 (ENS = 0.949 for full irrigation and 0.900 for limited irrigation), leaf area index in 2008 (ENS = 0.896 for full irrigation and 0.666 for limited irrigation), and yield (relative error, RE = 4.1% for full irrigation and -3.4% for limited irrigation). Simulation of late-season leaf area index in limited irrigation was underestimated, indicating model overestimation of water stress. Simulated cumulative ET trended similar to observed values, although the model showed some tendency to underpredict for full irrigation (RE = -7.2% over all years) and overpredict for limited irrigation (RE = 12.7% over all years). Limited irrigation observations showed a significant increase in WUE over full irrigation in two of the three years; however, the model was unable to replicate these results due to underestimation of ET differences between treatments. While CERES-Maize generally agreed with observed trends for full and limited irrigation scenarios, simulation results show that the model could benefit from a more robust water stress algorithm that can accurately reproduce plant responses such as those observed in this study.

Last Modified: 10/25/2014
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