Effects of Rice Straw Management on Sclerotium oryzae Inoculum, Stem Rot Severity, and Yield of Rice in California

Area of Science:

• Agricultural Science
• Plant Pathology
• Agronomy

Background:

• Open field burning was the standard for rice residue disposal and managing Sclerotium oryzae, the cause of rice stem rot.
• California's phase-down of burning necessitates alternative residue management strategies.
• Continuous rice cropping systems require effective disease control methods.

Purpose of the Study:

• To evaluate alternative rice residue management strategies.
• To assess the impact on Sclerotium oryzae inoculum and stem rot incidence/severity.
• To determine effects on rice yield in a continuous cropping system.

Main Methods:

• A 6-year split-plot experiment in Colusa County, California.
• Main plots: winter flooding vs. winter nonflooding.
• Subplots: straw incorporation, rolling, baling/removal, and burning.

Main Results:

• Winter flooding significantly reduced S. oryzae inoculum and disease severity, while increasing yield in 5 out of 6 years.
• Burning consistently resulted in the lowest S. oryzae inoculum across subplots.
• No consistent differences in disease or yield were observed among residue subplots, though burning yielded highest on average.

Conclusions:

• Winter flooding is the most effective alternative to burning for managing rice stem rot.
• Residue management strategies need to consider disease control and yield impacts.
• Sustainable practices are crucial for continuous rice cultivation.