Evaluation of DSSAT model for potential yield prediction of potato under autumn cropping system (Case study: Tropical regions of Jiroft, Iran)

Crop Simulation Models are advanced tools to estimate crop yield and optimizing of crop management practices. This study was conducted in order to evaluate DSSAT model under autumn cropping system condition in Jiroft, Iran, 2012 - 2014. The field experiment which repeated in two sequential years and three replications was performed with randomized complete block design in split plot. The main factor was planting date (17th, 23th, 29th September and 5th October) and its sub factor was potato cultivars (Sante, Satina and Boren). Data of first and second years of field experiment was applied respectively for calibration and evaluation of model. Data-base requirement for model was created from 1-climatic data includes: temperature, radiation, relative humidity, wind and precipitation, 2-crop data attained from field experiment, 3-soil data. Results of statistical evaluation of model showed the good fitness of yield simulated value and its actual value. In most cases, simulated tuber yield were similar to observed tuber production with a root mean square of 19% (1210 kg/ha). The R square index showed high correlation between observed and simulated value (Rsqr > 0.9). Simulated biomass had 2673.5 kg/ha difference to its observed value that was low precision estimation (RMSE > 30%). This model couldn’t predict tuber initiation stage correctly (RMSE > 30%). It was concluded however DSSAT model predicted potato yield but because of low precision in simulation of phonological stage and biomass value could not be used in autumn cropping system of potato.