Demir (2026) Strategic crop reallocation for reduced agricultural water footprints in semi-arid regions

Identification

• Journal: Irrigation Science
• Year: 2026
• Date: 2026-01-28
• Authors: Muhammed Sungur Demir
• DOI: 10.1007/s00271-026-01078-5

Research Groups

• Civil Engineering Department, Batman University, Batman, Türkiye

Short Summary

This study developed the first district-level water footprint (WF) optimization framework for Türkiye to minimize agricultural blue water consumption while maintaining national production quotas and district-level revenues. The framework demonstrated a potential reduction of approximately 32% in blue water use, 25% in total water footprint, and 22% in cultivated area under idealized assumptions.

Objective

• Construct district-level water footprint (WF) maps to quantify both blue and green water consumption across Türkiye’s agricultural sector.
• Develop a linear programming-based optimization framework to minimize blue water use while maintaining national production quotas and district-level revenue targets.

Study Configuration

• Spatial Scale: National (Türkiye), district-level (969 districts), aggregated to 25 major river basins.
• Temporal Scale: 10-year period (2013–2022) for meteorological and agricultural data, averaged to represent typical conditions.

Methodology and Data

• Models used:
  • FAO-56 methodology for Water Footprint (WF) calculation.
  • USDA Soil Conservation Service method (as implemented in FAO CROPWAT 8.0) for effective precipitation (Peff) estimation.
  • Strictly linear programming model (17,442 variables, 2,956 constraints) solved via MATLAB linprog for crop pattern optimization.
• Data sources:
  • Monthly meteorological data (precipitation, relative humidity, wind speed, solar radiation, minimum/maximum temperature) from 756 stations (2013–2022) by the Turkish State Meteorological Service (TSMS).
  • Crop-specific parameters (crop coefficients, growth durations) from the General Directorate of Agricultural Research and Policies (TAGEM).
  • District-level agricultural production data (harvested area, yield, total output) and crop prices from the Turkish Statistical Institute (TUİK).
  • DSİ irrigation statistics and CORINE 2018 land cover data for validation.

Main Results

• Türkiye’s total annual agricultural WF was estimated at 106.2 Gm³, comprising 67.3 Gm³ blue water and 38.9 Gm³ green water. Wheat and barley together account for approximately 60% of national agricultural water use.
• The optimization model indicates a potential reduction of approximately 32% (21 Gm³/year) in national blue water use, 13% (5 Gm³/year) in green water use, and 25% (26 Gm³/year) in total WF.
• Total cultivated area could be reduced by approximately 22% while maintaining national production quotas.
• Largest blue water savings occur in Central Anatolia and along the southern border (up to 425 Mm³ per district), with no river basin exceeding its baseline blue WF. The Euphrates–Tigris, Kizilirmak, and Konya Closed Basins achieve the largest absolute savings.
• Significant crop reallocations are identified, notably cotton shifting approximately 300 km northwest from arid southeastern provinces to the more humid Aegean coastal region.
• District-level revenues are maintained through crop substitutions, replacing lower-revenue crops with higher-revenue alternatives (e.g., sainfoin, vegetables).
• Sensitivity analyses confirm the robustness of the optimization outcomes to interpolation methods (90% concordance in dominant crop allocation) and moderate climate perturbations (proportional blue water reduction remains stable).

Contributions

• Developed the first district-level water footprint optimization framework for Türkiye that jointly enforces national production quotas and district-level revenue neutrality for 18 crops across 969 districts.
• Demonstrated a novel approach to integrate binding production and revenue constraints into spatial water footprint optimization for semi-arid regions.
• Provided a context-specific analytical framework for assessing spatial water-use efficiency, offering quantitative benchmarks for feasibility assessments and pilot-scale investigations in comparable agricultural systems.

Funding

• No specific projects, programs, or reference codes funded the research itself.
• Open access funding was provided by the Scientific and Technological Research Council of Türkiye (TÜBİTAK).

Citation

@article{Demir2026Strategic,
  author = {Demir, Muhammed Sungur},
  title = {Strategic crop reallocation for reduced agricultural water footprints in semi-arid regions},
  journal = {Irrigation Science},
  year = {2026},
  doi = {10.1007/s00271-026-01078-5},
  url = {https://doi.org/10.1007/s00271-026-01078-5}
}