The Response Characteristics of Sugarcane Yield, ET and WUE to Meteorological Drought Based on DSSAT-Canegro Model in Lai-bin, China

Abstract

Crop water use efficiency is an important indicator of the scientific and rational nature of agricultural water use. Studying the response characteristics of sugarcane yield accumulation and water use efficiency to meteorological drought scenarios is a key scientific issue to promote smart management and sustainable development of China's sugarcane industry. In this paper, based on SPEI index, different meteorological drought scenarios were set and the DSSAT-Canegro model was used to simulate the response mechanisms of sugarcane yield accumulation and canopy evapotranspiration to irrigation regime scenarios under different meteorological drought scenarios. Furtherly, in this study, the total on-farm water use efficiency (WUE_g), field water use efficiency (WP), true irrigation water use efficiency (WUE_ti), and irrigation water use efficiency (WUE_i) of sugarcane in the study area were evaluated quantitatively to screen the optimal irrigation regime. Specific studies have shown that the stem extension stage is the most sensitive growth stage for sugarcane response to irrigation. Soil evapotranspiration and crop transpiration in sugarcane fields in Laibin varied with irrigation quotas, and that reducing soil evapotranspiration could improve sugarcane water use efficiency. In meteorological drought scenarios with longer and more intense droughts, irrigation has a stronger stimulating effect on sugarcane growth and is more favourable to its yield accumulation.The correlations between WUE_g index and WP, WUE_i) and WUE_ti indicators of sugarcane in the study area were all significant, which can be used as key analytical indicators for the optimization of sugarcane irrigation regimes in Laibin. The results of this study can provide important scientific support for the accurate quantification of water demand and consumption of sugarcane in southern China and their coupled and coordinated intelligent management.