Planting aman rice at monsoon onset could mitigate the impact of temperature stress on rice-wheat systems of Bihar, India

Authors: MONTES, CARLO - International Maize & Wheat Improvement Center (CIMMYT); URFELS, ANTON - International Maize & Wheat Improvement Center (CIMMYT); Han, Eunjin; SINGH, BALWINDER - Department Of Primary Industries

Submitted to: Atmosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2022
Publication Date: 12/26/2022
Citation: Montes, C., Urfels, A., Han, E., Singh, B. 2022. Planting aman rice at monsoon onset could mitigate the impact of temperature stress on rice-wheat systems of Bihar, India. Atmosphere. 14(1):40. https://doi.org/10.3390/atmos14010040.
DOI: https://doi.org/10.3390/atmos14010040

Interpretive Summary: The rice-wheat rotation corresponds to the dominant cropping system in the state of Bihar in northern India. Therefore, the food security of the rural population of Bihar depends heavily on the production of rice and wheat. In this region, recurrent climatic shocks induced by low temperatures and terminal heat stress can significantly affect rice and wheat potential yields, respectively. In this sense, this study analyzed the benefits of agronomic monsoon onset as planting dates for reducing the incidence of thermal stresses in the rice-wheat system as an adaptation strategy. Compared to the current farmers' practice, rice planting based on agronomic monsoon onset would improve rice and wheat yields and yield stability by reducing the exposure of both rice to low temperatures and wheat to terminal heat stress. The results also show significant regional differences in planting dates and attainable rice-wheat yields for both rice planting scenarios across Bihar. The spatial differences in the potential benefit on yields of using the monsoon onset as a rice planting strategy could help focus efforts on developing and delivering actionable climate services to adapt to the increasing climate hazards in rice-wheat systems of Bihar in India.

Technical Abstract: Multiple studies have reported the adverse effects of low temperatures on rice and terminal heat on wheat in northern India. Although the foregoing is widely known, developing adaptation strategies at the regional level aligned with the current efforts in adaptation to climate change is a pending task. The present work evaluated the potential benefit of agronomic onset definitions to determine rice planting dates by reducing thermal stress in rice-wheat systems and, consequently, increasing the attainable yields of both crops. The current study used high-resolution gridded APSIM crop modeling framework to simulate potential yields of rice-wheat systems and two different planting scenarios, the estimated monsoon onset and current farmer's planting practices. The agronomic monsoon onset dates were calculated using daily rainfall observations, and farmer's practice planting dates were estimated using remotely sensed NDVI data. Model outputs were analyzed in terms of differences in estimated planting dates, yields, yield stability, and the incidence of low-temperature stress in rice and high-temperature stress in wheat by means of the corresponding yield-limiting factors of APSIM. The results show that the rice planting dates using the agronomic monsoon onset are, in general, about 20-30 days earlier than the farmer's practice. The foregoing has repercussions in a generally lower incidence of thermal stress in both rice and wheat. Consequently, planting rice based on agronomic monsoon onset dates generates higher and more stable yields for rice and wheat, especially in lower-yield areas. These results can help design adaptation strategies for the negative impacts of climate shocks induced by low- and high-temperature events, along with current advances in sub-seasonal and seasonal forecasts.