Oalib Open Access Library Journal 2333-9721 2333-9705 Scientific Research Publishing 10.4236/oalib.1114545 Oalib-147914 Article Biomedical Life Sciences Business Economics Chemistry Materials Science Computer Science Communications Earth Environmental Sciences Engineering Medicine Healthcare Physics Mathematics Social Sciences Humanities Impact of Climate Variability and Change on Sorghum Yield in Gedaref State, Sudan Hudo Noah Adam 1 Department of Meteorology, University of Nairobi, Nairobi, Kenya

The author declares no conflicts of interest.

 01 12 2025 12 2025 12 12 1 6 04 11 2025 08 12 2025 11 12 2025 © 2025 by the authors and Scientific Research Publishing Inc. 2025 This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( https://creativecommons.org/licenses/by/4.0/ ). https://doi.org/10.4236/oalib.1114545

Climate variability has become a major constraint to agricultural productivity in Sudan, particularly in rain-fed regions such as Gedaref State. This study analyzes the impacts of temperature and rainfall variability on sorghum yield using long-term climate data (1961-2014) and sorghum production records (1970-2007). Mann-Kendall trend tests, correlation, and multiple regression analyses were applied to assess climate-yield relationships. The FAO AquaCrop model was used to project future yield changes under changing climate conditions. Results revealed significant increases in maximum and minimum temperatures (p < 0.001) and a slight, insignificant decline in rainfall. Sorghum yield was positively correlated with rainfall (r = 0.59) and negatively correlated with maximum (r = −0.34) and minimum (r = −0.31) temperatures. Regression results indicated that climatic variables explained about 30% of yield variability (p = 0.02). AquaCrop simulations suggested that by 2046, rainfall may decrease by 33% and temperature rise by 2.4˚C, leading to a 39.9% yield decline. The findings highlight the vulnerability of rain-fed sorghum to climate variability and emphasize the need for adaptation measures to safeguard food security and rural livelihoods in Sudan.

 Climate Variability Sorghum Yield AquaCrop Model Gedaref Sudan Rain-Fed Agriculture 1. Introduction

Agriculture remains central to Sudan’s economy, employing most of the population and contributing nearly 40% to the national GDP [1]. Sorghum is one of the country’s most important cereal crops, providing both food and income for rural households. In Gedaref State, sorghum dominates rain-fed farming systems that rely heavily on seasonal rainfall. However, increasing temperatures and rainfall variability in recent decades have threatened agricultural production [2][3].

Studies from the Sahel and Horn of Africa regions have similarly shown that warming trends and erratic rainfall adversely affect crop yields [4]-[6]. Yet, few studies have quantified these effects for Gedaref. This study fills that gap by assessing long-term climate variability, examining its relationship with sorghum yield, and projecting future impacts using the AquaCrop model.

 2. Materials and Methods 2.1. Study Area

Gedaref State is located in eastern Sudan between latitudes 13˚N - 15˚N and longitudes 33˚E - 36˚E. The area has a semi-arid climate with one rainy season (June-October), characterized by annual rainfall ranging from 500 to 800 mm, and mean temperatures between 25˚C and 35˚C. Soils are predominantly clay, supporting extensive sorghum cultivation under rain-fed systems. See Figure 1Figure 1.

Figure 1. Map of Gedaref State, Sudan, showing the study area.

 2.2. Data Sources

Monthly rainfall, maximum and minimum temperatures, and potential evapotranspiration (1961-2014) were obtained from the Sudan Meteorological Authority. Sorghum yield data (1970-2007) were obtained from the Ministry of Agriculture and Forests. Climate projections for 2017-2046 were derived from the NCC-CORDEX regional model, driven by the HadGEM2-ES Global Climate Model (GCM) under the RCP 4.5 scenario, which represents a medium stabilization pathway.

 2.3. Analytical Methods

Trends in temperature and rainfall were analyzed using the Mann-Kendall test and Sen’s slope estimator. The coefficient of variation (CV) was used to assess interannual variability. Pearson correlation and multiple regression analyses determined the relationships between sorghum yield and climate variables. The FAO AquaCrop model [7] was used to simulate yield response under observed and projected climate conditions. The model was calibrated (R2 = 0.82, RMSE = 0.41 t/ha) with historical yield data and validated through observed-simulated comparison.

 3. Results and Discussion 3.1. Climate Trends

Both maximum and minimum temperatures and evapotranspiration increased significantly during the study period (p < 0.001). Rainfall showed high variability but a weak, statistically insignificant decline. These results are consistent with regional patterns of increasing temperature and rainfall variability observed across the Sahel and East Africa [3][8]. See Figure 2Figure 2.

Figure 2. Historical data trend analysis of rainfall, evapotranspiration and temperature, Gadaref area (1961-2014).

 3.2. Relationship between Climate and Sorghum Yield

Sorghum yield was positively correlated with rainfall (r = 0.59) and negatively correlated with maximum temperature (r = −0.34) and minimum temperature (r = −0.31), see Table 1. The multiple regression model indicated that climatic factors explained 30% of yield variability (p = 0.02). See Table 1.

Table 1.Correlation coefficients between sorghum yield and climatic variables.

Variables Correlation Coefficient T Calculated T Tabulated Relationship Description
Sorghum yield and rainfall 0.59 4.792 1.645 Significant
Sorghum yield and maximum temperature −0.34 −2.371 1.645 Significant
Sorghum yield and minimum temperature −0.31 −2.138 1.645 Significant
Sorghum yield and evapotranspiration 0.25 1.693 1.645 Significant

Rainfall remains the dominant factor determining yield variability in Gedaref. Reduced rainfall and increased temperature shorten the crop cycle and increase soil moisture stress. Physiologically, higher maximum temperatures during flowering can induce heat stress, reducing grain set, while higher minimum temperatures can increase nighttime respiration, reducing carbohydrate accumulation. Similar trends have been reported in other semi-arid regions of Sudan and East Africa [3][5].

To contextualize the regression result (30% of explained variance), non-climatic factors such as soil fertility degradation, limited fertilizer use, pest infestations, and policy constraints likely account for much of the unexplained yield variability.

 3.3. Projected Future Changes

AquaCrop simulations projected that by 2046, rainfall may decrease by 33% while temperatures rise by 2.4˚C (mainly driven by a significant increase in minimum temperatures) (see Table 2), resulting in an estimated 39.9% reduction in sorghum yield compared to the baseline period (see Figure 3Figure 3).

Table 2.AquaCrop simulation results showing projected yield changes.

Variables Average of Observed Data Average of Future Data (2046) Change Percentage Change
Rainfall (mm) 612.43 409.97 −202.46 −33.0%
Maximum temperature (˚C) 36.71 36.73 +0.02 +0.05%
Minimum temperature (˚C) 21.36 23.75 +2.39 +11.2%
Sorghum yield (simulated) — ↓ −39.9%

Figure 3. Simulated sorghum yield decline under future climate scenarios.

 3.4. Policy Implications

The results of this study underline the urgent need for climate-resilient agricultural strategies in Gedaref State. Policymakers should prioritize:

Promotion of drought-tolerant sorghum varieties and climate-smart farming practices.Investment in small-scale irrigation and water harvesting systems to reduce dependence on erratic rainfall.Enhancement of agricultural extension services and farmer capacity building on climate risk management.Integration of seasonal climate forecasting into local agricultural planning.Supportive policies that encourage sustainable soil management and access to inputs (fertilisers, seeds, technology).

These measures will help strengthen rural livelihoods and ensure food security under changing climate conditions.

 4. Conclusion

This study demonstrates that climate variability—especially increased temperature and reduced rainfall—significantly influences sorghum yields in Gedaref State. Climate factors accounted for roughly one-third of observed yield variability. Future projections suggest potential yield declines of about 40% by mid-century, posing a major threat to food security. Policy responses should focus on promoting climate-smart agriculture, water conservation, and resilient crop varieties to sustain productivity in rain-fed systems.

 Acknowledgements

The author expresses sincere gratitude to Dr. Fredrick K. Karanja, Department of Meteorology, University of Nairobi, for his valuable supervision and guidance. Appreciation is also extended to the Sudan Meteorological Authority and the Ministry of Agriculture and Forestry for providing data used in this research.

 Author’s Contribution

The author, Noah Adam Hudo, designed the study, collected and analyzed data, conducted modelling, interpreted results, and prepared the manuscript.

 References Elagib, N.A. (2011) Evolution of Drought in the Sahel and Sudan: Analysis Based on the Precipitation Index. Natural Hazards, 56, 129-146. Elagib, N.A. 2011 Evolution of Drought in the Sahel and Sudan: Analysis Based on the Precipitation Index Natural Hazards 56 FAO (2022) The State of Food and Agriculture 2022. Food and Agriculture Organisation of the United Nations. 2022 The State of Food and Agriculture 2022 Sarr, B., Wella, M. and Traore, S.B. (2020) Climate Variability, Sorghum Yield and Adaptation in West Africa. Theoretical and Applied Climatology, 141, 1265-1277. Sarr, B. Wella, M. Traore, S.B. Variability, S 2020 Climate Variability, Sorghum Yield and Adaptation in West Africa Theoretical and Applied Climatology 141 IPCC (2021) Climate Change 2021: The Physical Science Basis. Cambridge University Press. 2021 Climate Change 2021: The Physical Science Basis Osman, A.M., Ahmed, H.E. and Eltahir, E.A.B. (2022) Impacts of Climate Change on Sorghum Yield and Adaptation Strategies in Sudan. Agricultural and Forest Meteorology, 317, Article ID: 108900. Osman, A.M. Ahmed, H.E. Eltahir, E.A.B. 2022 Impacts of Climate Change on Sorghum Yield and Adaptation Strategies in Sudan Agricultural and Forest Meteorology 317 108900 ID Gebrechorkos, S.H., et al. (2023) Climate Change Impacts on Crop Productivity in East Africa: Evidence and Adaptation Pathways. Environmental Research Communications, 5, Article ID: 045006. Gebrechorkos, S.H. 2023 Climate Change Impacts on Crop Productivity in East Africa: Evidence and Adaptation Pathways Environmental Research Communications 5 045006 ID Steduto, P., Hsiao, T.C., Raes, D. and Fereres, E. (2009) AquaCrop—The FAO Crop Model to Simulate Yield Response to Water. AgronomyJournal, 101, 426-437. https://doi.org/10.2134/agronj2008.0139s 10.2134/agronj2008.0139shttps://doi.org/10.2134/agronj2008.0139s Steduto, P. Hsiao, T.C. Raes, D. Fereres, E. 2009 AquaCrop—The FAO Crop Model to Simulate Yield Response to Water Agronomy Journal 101 10.2134/agronj2008.0139s Wolde, M. and Tesfaye, K. (2024) Evaluating Adaptation Strategies for Rain-Fed Crops under Climate Change in the Horn of Africa. Climate and Development, 16, 23-37. Wolde, M. Tesfaye, K. 2024 Evaluating Adaptation Strategies for Rain-Fed Crops under Climate Change in the Horn of Africa Climate and Development 16