Post-Soviet changes in cropping practices in the irrigated drylands of the Aral Sea basin

Water withdrawals for irrigated crop production constitute the largest source of freshwater consumption on Earth. Monitoring the dynamics of irrigated crop cultivation is crucial for tracking crop water consumption, particularly in water-scarce areas. We analyzed changes in water-dependent crop cult...

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Bibliographic Details
Published in:Environmental research letters 2022-09, Vol.17 (9), p.95013
Main Authors: Rufin, Philippe, Peña-Guerrero, Mayra Daniela, Umirbekov, Atabek, Wei, Yanbing, Müller, Daniel
Format: Article
Language:English
Subjects:
Agricultural land
Arid lands
Arid zones
Central Asia
Crop production
Crop production systems
cropping frequency
Crops
Cultivation
Double cropping
Dry season
Estimates
Evapotranspiration
intensification
Irrigated areas
irrigation
land use intensity
Landsat
Moisture content
Rainy season
Remote sensing
Rivers
Seasons
Trajectory analysis
Tributaries
Water consumption
Water content
Water demand
Water resources
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Summary:Water withdrawals for irrigated crop production constitute the largest source of freshwater consumption on Earth. Monitoring the dynamics of irrigated crop cultivation is crucial for tracking crop water consumption, particularly in water-scarce areas. We analyzed changes in water-dependent crop cultivation for 650 000 km 2 of Central Asian drylands, including the entire basin of the Amu Darya river, once the largest tributary to the Aral Sea before large-scale irrigation projects grossly reduced the amount of water reaching the river delta. We used Landsat time series to map overall cropland extent, dry season cropping, and cropping frequency in irrigated croplands annually from 1987 to 2019. We scrutinized the emblematic change processes of six localities to discern the underlying causes of these changes. Our unbiased area estimates reveal that between 1988 and 2019, irrigated dry season cropping declined by 1.34 million hectares (Mha), while wet season and double cropping increased by 0.64 Mha and 0.83 Mha, respectively. These results show that the overall extent of cropland in the region remained stable, while higher cropping frequency increased harvested area. The observed changes’ overall effect on water resource use remains elusive: Following the collapse of the Soviet Union, declining dry season cultivation reduced crop water demand while, more recently, increasing cropping frequency raised water consumption. Our analysis provides the first fine-scale analysis of post-Soviet changes in cropping practices of the irrigated areas of Central Asia. Our maps are openly available and can support future assessments of land-system trajectories and, coupled with evapotranspiration estimates, changes in crop water consumption.
ISSN:1748-9326
1748-9326
DOI:10.1088/1748-9326/ac8daa