University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 48 5 2018 01 21 Calibration of AquaCrop’s normalized water productivity for corn production in Pakdasht region Calibration of AquaCrop’s normalized water productivity for corn production in Pakdasht region 1063 1071 64763 10.22059/ijswr.2017.224807.667610 FA Mohammad Ali Amopour University of Tehran Ali Rahimi Khoob University of Tehran Maryam Varavipour University of Tehran 0009-0005-2281-5598 Journal Article 2017 01 10 The normalized Water Productivity (WP^*) parameter is one of the inputs for the AquaCrop model upon which the daily basis biomass production is simulated. The default value determined for WP^* is 33.7 grams per square meter for the corn crop. The problem that this research intends to solve is the amount of normalized water productivity for the Single Crosses 704 cultivar of  corn, which  has not been determined yet. This study was conducted for two years (2015-2016) at an experimental farm of Aburaihan college belonging to the University of Tehran in Pakdashtregion. An overall of three plots were used for the experiment with an area size of 25 m² for each one. The biomass yield of corn was measured six and seven times during the growing season in 2015 and 2016, respectively. The data measured in the first year (2015) and second year (2016) were used for calibration and verification of the model, respectively. The calibration was carried out using two methods of trial and error and the method presented by Steduto et al. (2009). The WP^*was calibrated with a little more accuracy by the latter method, and its value was estimated as 32.3 grams per square meter. The root mean square error and the mean bias error for the comparison between the measured and estimated biomass production are 0.73 and 0.25 ton per hectare for the tested data. The normalized Water Productivity (WP^*) parameter is one of the inputs for the AquaCrop model upon which the daily basis biomass production is simulated. The default value determined for WP^* is 33.7 grams per square meter for the corn crop. The problem that this research intends to solve is the amount of normalized water productivity for the Single Crosses 704 cultivar of  corn, which  has not been determined yet. This study was conducted for two years (2015-2016) at an experimental farm of Aburaihan college belonging to the University of Tehran in Pakdashtregion. An overall of three plots were used for the experiment with an area size of 25 m² for each one. The biomass yield of corn was measured six and seven times during the growing season in 2015 and 2016, respectively. The data measured in the first year (2015) and second year (2016) were used for calibration and verification of the model, respectively. The calibration was carried out using two methods of trial and error and the method presented by Steduto et al. (2009). The WP^*was calibrated with a little more accuracy by the latter method, and its value was estimated as 32.3 grams per square meter. The root mean square error and the mean bias error for the comparison between the measured and estimated biomass production are 0.73 and 0.25 ton per hectare for the tested data. https://ijswr.ut.ac.ir/article_64763_75ba803a7ffe0085e17b6b0a530c051e.pdf