Manikandan et al. (2025) Agricultural drought propagation across major sorghum growing districts in Tamil Nadu, India

Identification

• Journal: Plant Science Today
• Year: 2025
• Date: 2025-11-06
• Authors: N. Manikandan, V. Geethalakshmi, Santanu Kumar Bal, NK Sathyamoorthy, Balaji Kannan, R Ravikumar
• DOI: 10.14719/pst.11536

Research Groups

• Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
• Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
• ICAR-Central Research Institute for Dryland Agriculture, Hyderabad, Telangana, India
• Department of Soil and Water Conservation Engineering, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India

Short Summary

This study quantified the spatial variations in meteorological and agricultural drought frequency and their propagation time at a weekly scale across major sorghum-growing districts in Tamil Nadu, India, revealing significant regional differences in drought response times.

Objective

• To quantify the spatial variations in meteorological and agricultural drought frequency and the transition time between them in major sorghum-growing districts of Tamil Nadu, India.

Study Configuration

• Spatial Scale: Major sorghum-growing districts of Tamil Nadu, India, using gridded data at 0.25° × 0.25° resolution (approximately 25 km).
• Temporal Scale: 34 years (1991-2024) of daily data, converted to weekly format, analyzed for two sorghum growing seasons (July-October and September-December).

Methodology and Data

• Models used:
  • Percent of Normal Precipitation (PNP) for meteorological drought characterization.
  • Soil Moisture Deficit Index (SMDI) for agricultural drought characterization.
  • Maximum Pearson Correlation Coefficient (MPCC) method to quantify drought propagation time.
• Data sources:
  • Daily gridded rainfall data (0.25° × 0.25°) from the India Meteorological Department (IMD).
  • Soil moisture data for three layers (up to 100 cm) from the ERA5 Land reanalysis dataset (0.25° × 0.25°), accessed via the Copernicus Climate Change Service (C3S) / European Centre for Medium-Range Weather Forecasts (ECMWF).
  • District-wise sorghum area, production, and yield data (2014-2023) from the Season and Crop Report, Department of Economics and Statistics, Government of Tamil Nadu, India.

Main Results

• The frequency of extreme meteorological drought (weekly rainfall <40% of normal) ranged from 34% to 68% during the first sorghum growing season and 40% to 55% during the second season across different districts.
• Moderate and severe dry conditions typically occurred for 1 to 2 weeks in both seasons.
• The highest frequency of moderate agricultural drought (50%) was observed in Ramanathapuram and Thoothukudi districts during the first season, and in Coimbatore and Thoothukudi districts during the second season.
• A shorter drought response time of 4 to 5 weeks was found in the western, southern, and central parts of Tamil Nadu (e.g., Coimbatore, Dindigul, Thoothukudi).
• A longer drought response time of 17 to 18 weeks was observed in the north-western and north-eastern districts of the state (e.g., Krishnagiri, Vellore).
• Shorter transition times were attributed to lower seasonal rainfall, higher frequency of extreme dry conditions during the first growing season, and the prevalence of fine-textured black and brown soils with shallow rooting depths.

Contributions

• Provides a novel quantification of the time lag from meteorological to agricultural drought at a finer temporal (weekly) and spatial (0.25° × 0.25° grid) resolution, which is less common in existing literature for the study region.
• Offers crucial insights into the spatial variability of drought propagation, which can significantly improve drought monitoring and aid in developing targeted strategies to mitigate crop losses.
• Identifies specific regions with shorter drought propagation times, highlighting areas that require rapid interventions, especially in light of projected increases in drought frequency and severity due to climate change.

Funding

• The study was part of the first author's PhD research, supported by study leave granted by ICAR-Central Research Institute for Dryland Agriculture, Hyderabad, Telangana.
• Facilities for conducting the research were provided by the Agro Climate Research Centre, Tamil Nadu Agricultural University.

Citation

@article{Manikandan2025Agricultural,
  author = {Manikandan, N. and Geethalakshmi, V. and Bal, Santanu Kumar and Sathyamoorthy, NK and Kannan, Balaji and Ravikumar, R},
  title = {Agricultural drought propagation across major sorghum growing districts in Tamil Nadu, India},
  journal = {Plant Science Today},
  year = {2025},
  doi = {10.14719/pst.11536},
  url = {https://doi.org/10.14719/pst.11536}
}

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