Effects of meteorological drought on sugarcane growth using DSSAT-Canegro model in Laibin, Guangxi of China

Abstract: Meteorological drought has been one of the most serious natural disasters that restrict the high yield and sugar content of sugarcane in recent years. Therefore, it is a high demand to clarify the response mechanism of sugarcane growth to meteorological drought, further to realize the intelligent management of sugarcane drought risk for the sustainable development of the sugar industry. In this study, a daily Standardized Precipitation Evapotranspiration Index (SPEI) was calculated to determine the meteorological drought characteristics, including the spatial pattern of drought intensity, duration, occurrence frequency, and scenarios during sugarcane growth periods. The multi-source daily meteorological datasets were also collected from the China Meteorological forces Dataset (CMFD) with 0.1° grid point and the surface meteorological station observation in Laibin City, Guangxi Autonomous Region of China from 1979 to 2018. A DSSAT-Canegro model was selected to simulate the response mechanism of sugarcane growth and yield accumulation to various meteorological drought scenarios. The meteorological drought intensity, duration, and frequency were then determined in different sugarcane growth periods, thereby designing the actual possible meteorological drought scenarios. In terms of the model validation, eight significant parameters of the DSSAT-Canegro model were screened out by the sensitivity analysis, where the deterministic coefficients were all over 0.95 between the parameter localization model and field experiment. The simulation results show that the greater the meteorological drought intensity and duration were, the stronger the sugarcane growth inhibition appeared on the Stalk Fresh Mass (SFM), Stem Height (SH), Leaf Area Index (LAI), and evapotranspiration (ET). Therein, the sugarcane LAI was the response of the most sensitive parameters to the meteorological drought during the stem extension stage. The light meteorological drought occurred in the seedling or maturity stage, and the moderate or severe meteorological drought occurred in the maturity stage. The sugarcane all presented the SFM-increasing effect under the water deficit stimulation, but the total SFM-increasing rate was less than 5%. A threshold of meteorological drought duration was determined 30d to distinguish the response, where the SFM-increasing effect in the seedling stage under light meteorological drought duration was less than 30 d, whereas, the SFM-decreasing effect in the same scenario was greater than 30d. Analogously, the threshold also served as an inflection point in the SFM-decreasing effect from the weak to strong during the seedling stage under the moderate meteorological drought scenario. Comparatively, the stem extension stage was the most significant period of sugarcane growth response to various meteorological drought scenarios. Specifically, there was an outstandingly SFM-decreasing effect in this period, where the SFM-decreasing rates were achieved 7.12% under the light, 16.48% under the moderate, 18.80% under the severe, and 29.05% under the extreme meteorological drought, respectively. In conclusion, the quantitative mapping was identified the SFM accumulation response to the ergodic intensity and duration of meteorological drought. The sugarcane drought chain transmission was determined among the meteorological drought, soil moisture, and sugarcane growth vigor. The finding can also provide important scientific support to realize the sugarcane drought dynamic risk simulation, regulation, and multistage early warning in Laibin City of China.