Mahmoud et al. (2025) Determining evapotranspiration of Faba bean and Chickpea using the soil water balance method under field conditions in in the Gezira Scheme, Sudan

Identification

• Journal: Discover Agriculture
• Year: 2025
• Date: 2025-12-15
• Authors: Mahmoud A. Mahmoud, Mohamed Husein, Mohie El Din Mohamed Omar
• DOI: 10.1007/s44279-025-00458-3

Research Groups

• Water Management Section, Land and Water Research Center, Agricultural Research Corporation (ARC), Wad Medani, Sudan
• International Center for Agricultural Research in the Dry Areas (ICARDA), Cairo, Egypt

Short Summary

This study quantified crop evapotranspiration (ETc) and developed growth-stage-specific crop coefficients (Kc) for faba bean and chickpea in the Gezira Scheme, Sudan, providing site-specific parameters to improve irrigation scheduling and water-use efficiency.

Objective

• Quantify the seasonal and average daily crop water requirements (ETc) of faba bean and chickpea.
• Establish growth-stage-specific crop coefficients (Kc) for the initial, development, mid-season, and late-season phenological stages under field conditions in the Gezira Scheme, Sudan.

Study Configuration

• Spatial Scale: Field-scale experiments in the semi-arid central Gezira Scheme, Wad Medani, Sudan (14°23′ N, 33°29′ E; 405 m above sea level).
• Temporal Scale: Two winter growing seasons (November to March) for 2021/2022 and 2022/2023.

Methodology and Data

• Models used: FAO Penman–Monteith method (implemented in CROPWAT 8.0), Soil Water Balance method, Microsoft Excel (Version 2021), R Statistical Software (Version 4.5.1).
• Data sources: Field gravimetric soil moisture measurements (0-60 cm depth), daily meteorological data (temperature, relative humidity, sunshine duration, wind speed) from Wad Medani Meteorological Station, in-situ irrigation water volume measurements, visual crop ground cover estimations, crop yield measurements.

Main Results

• Average seasonal crop evapotranspiration (ETc) was 435 mm for faba bean and 380 mm for chickpea.
• Peak daily ETc occurred during the mid-season stage, reaching 6-7 mm day⁻¹ for faba bean and 5-6 mm day⁻¹ for chickpea, with this stage accounting for 51% of total seasonal water use for both crops.
• Growth-stage-specific crop coefficients (Kc) for faba bean were 0.31 (initial), 0.85 (development), 1.07 (mid-season), and 0.55 (late-season). For chickpea, they were 0.28 (initial), 0.71 (development), 1.04 (mid-season), and 0.30 (late-season).
• Faba bean ETc showed a positive correlation with reference evapotranspiration (ETo) (R² = 0.214) but a negative correlation with maximum temperature (R² = 0.235), while chickpea ETc showed weaker correlations.
• Using FAO-56 default Kc values would overestimate seasonal ETc by 12.1% (52.5 mm) for faba bean and 2.7% (10.3 mm) for chickpea compared to locally derived values.
• Initial Kc values were lower than FAO-56 defaults, attributed to Vertisols' self-mulching effect, while late-season Kc for faba bean was higher, indicating prolonged transpiration.

Contributions

• Provides the first calibrated, site-specific crop evapotranspiration (ETc) and growth-stage-specific crop coefficients (Kc) for faba bean and chickpea under the unique Vertisol and semi-arid conditions of the Gezira Scheme, Sudan.
• Demonstrates that standard FAO-56 Kc values are inadequate for this specific region, leading to significant overestimation of water requirements (up to 12.1% for faba bean).
• Offers a scientific basis for evidence-based irrigation scheduling, enabling more precise water application and potentially reducing seasonal irrigation water use by 12% for faba bean and 3% for chickpea without yield penalties.
• Enhances water-use efficiency and supports sustainable legume production in a water-scarce region, addressing a critical knowledge gap in irrigation management.

Funding

• Project: Strengthening Innovation and Technology Adoption towards Sustainable Agricultural Productivity in Arab Countries
• Funder: Arab Fund
• Technical Support: International Center for Agricultural Research in the Dry Areas (ICARDA)
• Support: Gezira Research Station

Citation

@article{Mahmoud2025Determining,
  author = {Mahmoud, Mahmoud A. and Husein, Mohamed and Omar, Mohie El Din Mohamed},
  title = {Determining evapotranspiration of Faba bean and Chickpea using the soil water balance method under field conditions in in the Gezira Scheme, Sudan},
  journal = {Discover Agriculture},
  year = {2025},
  doi = {10.1007/s44279-025-00458-3},
  url = {https://doi.org/10.1007/s44279-025-00458-3}
}