Evapotranspiration (
ETc), crop water requirement (
Dcr), irrigation (
IR) and irrigation leaching amount (
IRlc) play a critical role in optimizing irrigation scheduling and are also important for hydrological cycle processes and ecological environment in arid regions. This research examined the spatiotemporal variability of the
ETc,
Dcr and
IR of cotton using data from 16 meteorological stations in the Tarim basin (TRB) of arid Northwest China during 1961–2017. The results showed that the mean annual
ETc of cotton exhibited a significant decreasing trend, with a change rate of 12.965 mm·10 a
−1 and 18.357 mm·10 a
−1 during 1961–2017 and 1961–1990, respectively. Subsequently, it experienced a substantial increase with a change rate of 16.833 mm·10 a
−1 after 1990. The
Dcr of cotton followed a decreasing trend at a rate of 15.531 mm·10 a
−1 and 21.99 mm·10 a
−1 during 1961–2017 and 1961–1990, respectively. The
Dcr of cotton provided an increasing trend at a rate of 20.164 mm·10 a
−1 during 1991–2017. The
IR of cotton followed a decreasing trend at a rate of 19.66 mm·10 a
−1 in 1961–2017 and 24.531 mm·10 a
−1 in 1961–1990, but an increasing trend at a rate of 14.437 mm·10 a
−1 in 1991–2017. The
IRlc of cotton decreased by 2.566 mm·10 a
−1 and 3.663 mm·10 a
−1 during 1961–2017 and 1961–1990, respectively. After 1990, it experienced a substantial increase by 3.331 mm·10 a
−1. Wind speed exerted the greatest influence on the variability in
Dcr and
IR between 1961 and 1990, while shine hour played a more prominent role in explaining the variability in
Dcr and precipitation may have played a more significant role in explaining the variability in
IR. This study is helpful for the scientific planning for agriculture, water resource allocation and water-saving irrigation in arid regions.
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