Evaluation of AquaCrop model for greenhouse cherry tomato with plastic film mulch under various water and nitrogen supplies

Abstract

Assessing and optimizing crop management strategies, e.g. irrigation and nitrogen (N) fertilization, is critical for the sustainable production of crops. Currently, crop simulation models combined with experimental data have been proved to be effective tools. Herein, the FAO AquaCrop model was calibrated and validated based on field-measured data during two consecutive growing seasons (2020 and 2021) for predicting canopy cover (CC, %), aboveground biomass and soil water content (SWC, mm) on a daily scale, and for simulating final fruit yield, evapotranspiration (ET, mm) and water productivity (WP, kg m−3) on a seasonal scale under plastic film mulch condition. The two-year experiment included three irrigation levels (60 %, 80 % and 100 % ET0, where ET0 is the reference evapotranspiration) and five N fertilizer rates (0, 180, 270, 360 and 450 kg N ha−1). In general, the AquaCrop model adequately simulated the dynamic changes of cherry tomato CC, aboveground biomass and final fruit yield. Nonetheless, the model severely overestimated SWC especially under full irrigation in the two-year experiment, and the simulation accuracy gradually increased with the increase of N rate. For ET, it was largely underestimated. With the decrease in irrigation level and N rate, the simulation accuracy improved and the impact of water stress was stronger than that of nitrogen stress. The simulation accuracy of WP decreased as irrigation level and N rate increased. The optimal integrated regime was deficit irrigation of 80 % ET0 combined with N rate of 360 kg ha−1 (I80N360), which obtained 98.24 % of potential yield while significantly decreasing water input. The simulation of the mulched module and parameters of the AquaCrop model (crop transpiration, water productivity, etc.) should be further optimized and verified. If these improvements can be made, the AquaCrop model can be used in the decision-making of irrigation and N fertilization strategies of cherry tomato under plastic film mulch condition.