Sowing date optimization mitigates cadmium accumulation in rice-ratoon rice cropping systems

Area of Science:

• Agricultural Science
• Environmental Science
• Food Safety

Background:

• Cadmium (Cd) contamination in rice is a significant global concern.
• Limited data exists on how sowing dates affect Cd accumulation in ratoon rice (RR) and associated health risks.
• This study addresses this knowledge gap using a field experiment in Cd-contaminated soil.

Purpose of the Study:

• To investigate the impact of different sowing dates on Cd accumulation in main season and ratoon rice.
• To assess the associated health risks of Cd accumulation in brown rice under various sowing scenarios.
• To identify optimal sowing strategies for mitigating Cd contamination in rice-ratoon rice systems.

Main Methods:

• Conducted a two-season field experiment with two rice genotypes and eight sowing date treatments (April-July) on Cd-contaminated soil.
• Analyzed Cd concentrations in brown rice and assessed health risks.
• Employed structural equation modeling to determine the influence of environmental factors like rainfall, temperature, and illumination on Cd accumulation.

Main Results:

• Ratoon rice season showed higher Cd concentrations and health risks with specific sowing dates compared to the main season.
• In the main season, early sowing increased Cd in short-duration rice, while delayed sowing affected long-duration rice differently.
• Rainfall negatively impacted Cd accumulation, while temperature and illumination showed season-specific effects.

Conclusions:

• Optimizing sowing dates according to regional climate is crucial for reducing Cd accumulation in rice-ratoon rice.
• Strategic sowing can significantly mitigate health risks associated with Cd contamination in rice.
• This research provides a basis for sustainable rice cultivation practices in Cd-affected areas.