Landsat time series reveal simultaneous expansion and intensification of irrigated dry season cropping in Southeastern Turkey

Abstract

Long-term monitoring of the extent and intensity of irrigation systems is needed to track crop water consumption and to adapt land use to a changing climate. We mapped the expansion and changes in the intensity of irrigated dry season cropping in Turkey´s Southeastern Anatolia Project annually from 1990 to 2018 using Landsat time series. Irrigated dry season cropping covered 5,779 km² (± 479 km²) in 2018, which represents an increase of 617% over the study period. Dry season cropping was practiced on average every second year, but spatial variability was pronounced. Increases in dry season cropping frequency were observed on 40% of the studied croplands. The presented maps enable the identification of land use intensity hotspots at 30 m spatial resolution, and can thus aid in assessments of water consumption and environmental degradation. All maps are openly available for further use at

Mapping ‘Life on Land’

“…For example, the anticipated increase of irrigated systems is about 4 times lower than the increase we projected (66%). A recent study found that irrigation in the southern part of Anatolia increased by more than 6 times in the last 30 years (Rufin et al, 2021) and a similar trend can be expected for other arid areas in the country, depending on available resources. It has to be noted that the voluntary targets are until 2030, while our projections were for the year 2050.…”

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

“…In this study, we mapped historic changes in cropping practices by classifying distinct crop growing cycles discerned from intraannual satellite image time series. This methodology contributes essential data about land and water use intensity in dryland regions and allows for fine-scale examinations of the determinants of land use change (Conrad et al 2016, Rufin et al 2019, 2021a.…”

“…during the wet season, the dry season, or both (Bégué et al 2018). This reduces the need for ground-based croptype reference data (Rufin et al 2021a) while enabling insight into the dynamics of land use intensity and crop water use (Conrad et al 2016).…”

Rapid expansion of irrigated agriculture in the Senegal River Valley following the 2008 food price crisis

“…Our analysis demonstrates the potential for Earthobservation analysis to document spatio-temporal patterns of irrigation expansion in regions such as the SRV, where in-situ monitoring is currently sparse and likely impractical to expand further in the future. EO time series of irrigated croplands can shed light on the performance and success of irrigation development programmes and policies, helping guide and inform ongoing efforts to deliver improvements in agricultural water security and climate change adaption (Deines et al 2019, Rufin et al 2021. In the SRV, we provide compelling evidence for the rapid recent expansion of irrigated croplands driven by responses to global commodity price spikes, whilst also highlighting the overall failure of many irrigation projects in the region to deliver on originally stated proposals to expand dry season production areas.…”

“…Data typically are too coarse to identify reliably smallholder farms that dominate agricultural landscapes, and commonly cover a single year or selected snapshots in time, limiting capacity to support analysis of temporal dynamics of water management policies and investments. More recently, studies in other regions have demonstrated continuous mapping of expansion and intensification of irrigation using machine learning analysis of stacks of moderate-resolution Landsat-derived annual spectral metric composites (Deines et al 2019, Rufin et al 2021. However, to date, these applications have focused on nations dominated by large-scale agriculture.…”