Manganese Toxicity Impairs Soil Nitrification and Sugarcane Nitrogen Utilization by Inhibiting Rhizosphere Ammonia-Oxidizing Microorganisms

Sugarcane (Saccharum spp.) is an economically vital crop cultivated primarily for sugar and bioethanol production. In southern China, sugarcane grown in acidic soils often exhibits severe leaf chlorosis due to excessive soil manganese (Mn) levels. However, the mechanisms by which Mn toxicity disrupts soil nitrogen (N) cycling, particularly the roles of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in regulating nitrification and N availability for sugarcane remain underexplored.