The objective of this study was to evaluate the effect of organic-matter incorporated into the soil on population densities of the causal agents of the dry rot disease of yam, under field conditions. The experiment was performed in a natural infested area with a mixed population of Pratylenchus coffeae and Scutellonema bradys, in Quebrangulo county (Alagoas state, Brazil) in a randomized block design with five treatments and five replicates. The sources of organic matter used as soil amendments were: coconut husk powder, castor bean cake, cattle manure and chicken manure. Non amended soil was used as a control. Nine months after planting, the tubers were harvested. No statistical differences were found among disease incidence, yam production and nematode population densities in the soil. However, the application of chicken manure reduced P. coffeae population in tubers. Key words: Dioscorea spp., Scutellonema bradys, Pratylenchus coffeae, nematode management.