The efficiency of the APSIM model in estimating yield and yield gaps in winter wheat and barley

Abstract The aim of this study was to evaluate the effectiveness of the Agricultural Production Systems sIMulator (APSIM) model in estimating yield and yield gaps for winter‐sown wheat ( Triticum aestivum L.) and barley ( Hordeum vulgare L .) in Alborz Province, Iran. Initially, the APSIM‐Wheat and APSIM‐Barley sub‐models (version 7.1) were parameterized for the target cultivars, and model performance was evaluated under a variety of conditions. Model calibration and validation required meteorological data, regional agronomic management approaches, and cultivar‐specific genetic coefficients. These data were gathered over a 4‐year period, with both field and on‐farm components. Two‐year field experiments were conducted to calibrate the model at the Atomic Energy Organization farm (2014–2015) and the University of Tehran's Faculty of Agriculture (2016–2017), using a randomized complete block design with 12 treatments (six wheat and six barley cultivars) and three replications. Under optimal conditions, wheat and barley in Alborz Province might produce average grain yields of 10,800 and 10,350 kg/ha, respectively. The yield gap research found that the wheat yield gap at levels 1–4 was 18.5%, 14.9%, 26.5%, and 18.3%, respectively, while the barley yield gap was 29.5%, 3.1%, 24.0%, and 23.7%. Irrigation schedule, total water use, and sowing date were key management factors that influenced yield gaps. The data indicate that using the best agronomic practices can greatly increase productivity and resource efficiency. Furthermore, the APSIM model has been shown to be an effective tool for crop management prediction, scenario analysis, and informed decision‐making.