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Arid Land Geography ›› 2023, Vol. 46 ›› Issue (10): 1632-1642.doi: 10.12118/j.issn.1000-6060.2022.616

• Biology and Pedology • Previous Articles     Next Articles

Remote sensing estimation of cotton water productivity in Ugan-Kuqa River Oasis based on Google Earth Engine

HE Xugang1,2,3(),Mamat SAWUT1,2,3(),SHENG Yanfang1,2,3,LI Rongpeng1,2,3   

  1. 1. College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, Xinjiang, China
    2. Xinjiang Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, Xinjiang, China
    3. Key Laboratory of Smart City and Environment Modelling of Higher Education Institute, Xinjiang University, Urumqi 830046, Xinjiang, China
  • Received:2022-11-21 Revised:2022-12-22 Online:2023-10-25 Published:2023-11-10

Abstract:

An accurate and quantitative evaluation of crop water productivity is the basis for the improvement of crop yield in arid regions and is of great significance to alleviate water shortage and drive sustainable agricultural development. We have considered the Ugan-Kuqa River Oasis on the north bank of the Tarim Basin of China as the subject area, and the watershed SEBAL remote sensing evapotranspiration model and cotton distribution identification model are established employing the Google Earth Engine cloud platform from 2009 to 2020. The production estimation model was used to evaluate the moisture productivity of cotton in the watershed. The following results were observed. (1) The cotton production in the Ugan-Kuqa River Oasis ranges from 1610.10 kg·hm-2 in 2009 to 1855.05 kg·hm-2 in 2020, with a growth rate of 13.20%. The cotton planting area extends to the edge of oasis year by year, and the center of gravity of cotton production moves 2485 m from west to east. (2) The average evapotranspiration (ET) value during the cotton growth period was 686.80 mm in 2009 and was 738.66 mm in 2020, indicating an overall upward trend, with a growth rate of 7.02%. The maximum value of ET during the cotton growth period was observed during the flowering and boll-opening stages. The higher ET value is mainly distributed in the interior of the oasis and at the edge of the north bank of the Tarim River. (3) The average water productivity in 2009 and 2020 was 0.21 kg·m-3 and 0.25 kg·m-3, respectively, indicating a growth rate of 16% in 12 years. In terms of space, the gravity center of water productivity in the Ugan-Kuqa River Oasis moved 1832 m from the northeast to the southwest of Hongqi Town, with an average annual moving speed of 152.67 m·a-1. The water productivity of oasis cotton showed an expanding trend in the east-west direction compared with that in the north-south direction. The trend of spatial distribution direction had been enhanced, and the spatial pattern tended to be agglomerated. (4) After 12 years, the increased yield rate exceeded the increased evapotranspiration rate, promoting the increase of water productivity. Moreover, water productivity is closely related to the cotton planting area and reasonable water irrigation technology. High water productivity is mainly distributed in Xinken Farm in Xayar County and Sangtamu Farm in Xinhe County, respectively. The large-scale planting and intensive management of farms promoted and improved cotton production, stable distribution, and efficient use of agricultural water resources.

Key words: Google Earth Engine (GEE), evapotranspiration, cotton extraction, cotton yield, water productivity, Ugan-Kuqa River Oasis