Implementing the dual crop coefficient approach in interactive software: 2. Model testing
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Date
2011-11-16
Date Issued
2012-01-01
ISI Journal
Impact factor: 4.021 (Year: 2011)
Citation
Ricardo D. Rosaa, P. Paredes, Goncalo C. Rodrigues, Rui M. Fernando, Isabel Alves, Luis Santos Pereira, Richard G. Allen. (1/1/2012). Implementing the dual crop coefficient approach in interactive software: 2. Model testing. Agricultural Water Management, 103, pp. 62-77.
Abstract
This paper is the second of a two-part series, with the first part describing the SIMDualKc model, an
irrigation scheduling simulation tool that employs the dual crop coefficient approach for calculating
daily crop ET and then performs a water balance for a cropped soil. The model was applied, calibrated
and validated for rainfed and basin irrigated maize (Coruche, Portugal), rainfed and surface irrigated
wheat (Aleppo, Syria), and furrow irrigated cotton (Fergana, Central Asia). Results show good agreement
between available soil water content observed in the field and that predicted by the model. Results
indicate that the calibrated model does not tend to over- or underestimate available soil water over the
course of a season, and that the model, prior to calibration, and using standard values for many parameters,
also performed relatively well. After calibration, the average growing season maximum estimation errors
were 10 mm for maize, 8 mm for winter wheat and 9 mm for cotton, i.e., respectively 3.6, 2.9 and 5.0%
of total available water. Results indicate that the separation between evaporation and transpiration and
the water balance calculation procedures are accurate enough for use in operational water management.
The indicators used for assessing model performance show the model to accurately simulate the water
balance of several crops subjected to a variety of irrigation management practices and various climate
conditions. In addition, the model was applied to alternative irrigation management scenarios and related
results are discussed aiming at assessing the model’s ability to support the development of alternative
active water management strategies.