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摘要
Frequent occurrence of extreme drought events has great impacts on cotton production in Central Asia. In this study, data from field experiments designed for different sowing densities and irrigation levels at the Zangiata experimental station in the Tashkent of Uzbekistan were adopted for calibration and validation. Using the CMIP6 climate change datasets for three shared socioeconomic pathways (SSP1-2.6, SSP3-7.0 and SSP5-8.5), we analyzed the variations in the standardized precipitation evapotranspiration index in three-month steps (SPEI-3) within the growing seasons from May to August during the period from 2021 to 2090 and simulated the changes in cotton yields under meteorological drought conditions using the APSIM-Cotton model considering CO2 fertilization. The results showed that the APSIM-Cotton model accurately simulated the cotton yield in Tashkent, and the relative errors between the simulated and measured yields were lower than 10.4% in both the calibration and validation years. Both temperature and drought frequency are expected to increase in the future during the cotton growing period in Tashkent. For the SSP3-7.0 and SSP5-8.5 scenarios, the percentages of severe drought are 36.7% and 40.0% from 2021 to 2050, respectively, and the percentages of extreme drought are 66.7% and 86.7% from 2061 to 2090, respectively. Severe meteorological droughts under three emission scenarios (SSP1-2.6, SSP3-7.0, and SSP5-8.5) would cause reductions of 28.0%, 29.6%, and 32.1% in cotton yields from 2021 to 2050, respectively, compared with the period 1961-1990. Severe meteorological droughts under the SSP1-2.6 scenario would result in a reduction of 31.5% in cotton yield from 2061-2090. Under the SSP3-7.0 and SSP5-8.5 scenarios, severe meteorological droughts would result in reductions of 33.1% and 35.7% in cotton yield, respectively, and extreme meteorological droughts would cause reductions of 41.3% and 54.2% in cotton yields, respectively. CO2 has a certain fertilization effect. The rise in CO2 concentration would increase the cotton yield by 14.9% to 25.0%; however, the increase in yields will not be sustained at concentrations above 750 μmol/mol. The results will provide scientific data for planting strategies for cotton in Central Asia that account for climate change and a reference for the future cooperation mode of the cotton industry between China and Central Asian countries.
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单位中国科学院; 中国科学院大学
