Abstract: Based on data of daily average temperature from 48 meteorological stations in Populus euphratica distribution areas of Chinese oases from 1960 to 2017, we analyzed spatiotemporal responses of the start and end dates as well as the number of days of growing period of P. euphratica to global warming hiatus, with multiyear trend line, correlation analysis, and partial leastsquares regression. The results showed that the change rates of start date, end date and the number of days of growing period of P. euphratica in Chinese oases from 1998 to 2012 were -0.764, -0.328, and 0.535 d·10 a^-1, respectively. In comparison with temporal sequence between 1960 and 2017 and that between 1960 and 1998, the start date had been postponed, the end date had been advanced and the number of days of growth period had been dwindled during 1998-2012, indicating high sensitivity to the global warming hiatus and with the highest sensitivity of the end date. In accordance to spatial variation, the response to global warming hiatus decreased from the southwest to the northeast, with more than 47% of stations showing the trend of postponed start date, advanced end date, and shrinking growing period. Response of growing period of P. euphratica to global warming hiatus varied across oasis sites. P. euphratica in Hetao oases had prominent response to global warming hiatus, while the response of P. euphratica in Qaidam oases was weak. Results of causal analysis showed that Asia polar vortex area index, Qinghai-Tibet Plateau index, and Westerly Circulation index were major factors driving the responses of P. euphratica to global warming hiatus.

Key words: leaf senescence., controlled release urea, water and N coupling, summer maize