1Department of Environmental Sciences, Tamil Nadu Agricultural University, Coimbatore641 003, Tamil Nadu, India
2Department of Renewable Energy Engineering, Agricultural Engineering College & Research Institute, Tamil Nadu Agricultural University, Coimbatore641 003, Tamil Nadu, India
3Department of Physical Sciences and Information Technology, Agricultural Engineering College & Research Institute, Tamil Nadu Agricultural University, Coimbatore641 003, Tamil Nadu, India
4Department of Soil and Water Conservation Engineering, Agricultural Engineering College & Research Institute, Tamil Nadu Agricultural University, Coimbatore641 003, Tamil Nadu, India
*Corresponding author mail: antorashwin@gmail.com
Online Published on 08 May, 2026.
Understanding seasonal energy subtleties is essential for optimizing rice cultivation under changing climatic conditions. This study evaluates the thermal and radiation use efficiency of rice variety CO 47 across seven major sowing windows, Navarai, Sornavari, Kar, Kuruvai, Samba, Thaladi, and Late Thaladi, in Coimbatore district, Tamil Nadu. Using 21 years (2004–2024) of daily climatic data from NASA POWER, thermal indices such as Growing Degree Days (GDD), Photothermal Units (PTU), and Heliothermal Units (HTU) were computed alongside derived efficiencies, Heat Use Efficiency (HUE), and Radiation Use Efficiency (RUE), for vegetative, reproductive, and maturity phases. Results revealed that the Sornavari and Navarai seasons exhibited the highest cumulative thermal and radiation indices, supporting robust crop development. Mid-year sowings like Kar and Kuruvai balanced thermal and radiation efficiency, while late Thaladi faced significant climatic constraints, particularly during reproductive stages. HUE peaked in early-season sowings, whereas RUE was highest in mid-year crops. These findings stress the need for seasonspecific agrometeorological strategies to enhance rice productivity and resilience under variable climates.
Rice (CO 47), Heat Use Efficiency (HUE), Radiation Use Efficiency (RUE), Growing Degree Days (GDD), Seasonal Sowing Windows, NASA POWER, Thermal Indices, Tamil Nadu, Agrometeorology, Crop Phenology
