Sugarcane water requirement and yield projections in major producing regions of China under future climate scenarios

Relative soil moisture is of great significance to the growth and yield of sugarcane. In this study, we use the relative soil moisture from the China Meteorological Administration Land Data Assimilation System (CLDAS) to dynamically evaluate the water requirement of sugarcane and its growth adaptability at different growth stages. Based on the data of relative soil moisture, air temperature, precipitation, and soil temperature, a sugarcane yield model is established to analyze the projected change trends of sugarcane yield in China from 2020 to 2100 under three future scenarios. Analysis results show that sugarcane requires more water during the elongation stage but less water at the ripening stage. The relative soil moisture from the CLDAS can be used to calculate the proportion of the daily suitable area to the total planting area. The combining of relative soil moisture data and water requirement indicators can better characterize the water requirement during sugarcane growth. Suitable relative soil moisture during the tillering and elongation stages is the most critical factor that directly affects the sugarcane yield. From 2020 to 2100, sugarcane yield will increase first and then decrease sharply. The increase in emissions can lead to an apparent downward trend in sugarcane yield. Based on the CLDAS data and water requirement indicators, a new method for monitoring the sugarcane growth throughout the growth period is proposed in this study. In the SSP370 and SSP460 scenarios, the sugarcane yield showed a downward trend, and there were mutations in 2064 and 2052, respectively. After the mutation, the yield decline trend was more obvious. Under the SSP585 scenario model, the sugarcane production showed an upward trend from 2022 to 2033 and a downward trend after 2033, and a mutation occurred in 2051. After the mutation, the downward trend of sugarcane production was more obvious.