We studied the effect of five bedding materials (wood shavings, sawdust, peanut hulls, wheat straw and shredded paper) and PLT (TM) (a commercial formulation of Na bisulfate) in factorial combinations, on NH3 emissions from broiler manure. Treatments were incubated for 11 days at 25 C and 98% relative humidity. Ammonia was trapped in 0.1 N H2SO4 and measured colorimetrically as NH4+, and CO2 was monitored with an infrared analyzer. Ammonia and CO, emissions were suppressed by PLT (TM) throughout the study. Wheat straw, wood shavings, and sawdust, with C(total)/N(total) > 50 or C(biodegradable)/N > 20, had low NH3 emissions. Total NH3 emissions from peanut hulls and shredded paper were the highest, probably due to peanut hulls' low C/N ratio and shredded paper's alkaline pH. No significant interactions on NH3 emissions were detected between PLT (TM) and bedding materials. (c) 2007 Elsevier Ltd. All rights reserved.