Incorporating straw may induce sulfide toxicity in paddy rice

Sulfide toxicity to rice plants has been randomly observed in isolated sites in rice fields and experimental plots in the Sacramento Valley. Plants suffering from sulfide toxicity show signs of retarded growth and reduced yields, including the characteristic blackened roots and, in the most severe cases, death. Because the environmental conditions causing sulfide toxicity are not clear, we carried out a greenhouse pot test. The treatments included straw and sulfate additions to a rice soil to induce sulfide production. Our results contribute to an improved definition of conditions leading to sulfide production, toxicity and impact to rice plants.