Application of DSSAT model to evaluate the effects of tillage methods on soil water balance during drought period

Abstract By impeding soil water movement, conventional tillage might exacerbate the impacts of drought in agricultural crop production. A modelling approach was employed in this study to evaluate conservation tillage methods as an alternative drought adaptation strategy. To do so, the Decision Support System for Agrotechnology Transfer (DSSAT) model was validated against in-situ soil moisture measurements by cosmic ray neutron sensor (CRNS) and point based PlantCare sensors. The study was conducted based on soil moisture measurements taken at a farm field in Adenstedt, Lower Saxony, Germany divided into three different sections based on tillage types (moldboard, disk harrow, and chisel plow). Subsequently, DSSAT model simulations were run to assess the effect of tillage methods on soil water balance components during drought. Results showed that the soil moisture at 0–15 cm depth simulated by the DSSAT model showed a better agreement with the CRNS measurement (KGE = 0.73, RMSE = 0.043 cm 3 /cm 3 , PBIAS = − 10.7%, r = 0.75 and R 2 = 0.58) than PC sensors. Furthermore, using the model to simulate the effect of conservation measures showed that mulching reduces soil evaporation by approximately 40% regardless of the conventional tillage type used. The reduction in soil evaporation by mulching was more pronounced in the emergence period, which is the most drought sensitive stage of sugar beet, implying the benefits of mulching in conserving soil moisture during drought period.