Many types of antibiotics are believed to be incorporated into poultry feed at between 1 and 55 mg kg-1, most of which are excreted in manure and applied to agricultural fields. There are several concerns associated with this practice, which include altering microbial communities and hastening the spread of antibiotic resistant bacteria in the environment through horizontal gene transfer and other mechanisms. The main objectives of this study are to determine (i) the types of antibiotic resistant bacteria in poultry manure, (ii) the effects of manure antibiotics on soil bacterial community structure, and (iii) relationships between community structure, manure placement position along a soil catena, and associated environmental factors (e.g. soil moisture, organic matter, and temperature). These objectives will be accomplished through a series of laboratory microcosm and field investigations using different soils variously amended with manure and antibiotics. Changes in the types of antibiotic resistant bacteria and bacterial community composition in soils and manure will be determined using molecular genetic techniques (e.g. denaturing gradient gel electrophoresis and cloning-sequencing) and non-parametric multivariate techniques (e.g. Manova and non-metric multidimensional scaling). It is expected that soil bacteria will acquire resistance after being exposed to antibiotic resistant bacteria in manure, depending on such factors as soil mineralogy, nutrient availability, temperature and moisture conditions that can vary widely in the landscape, such as along a soil catena. It is hoped that results from this study will be helpful to farm managers and regulators that need to make informed decisions about where to apply litter in landscapes in order to reduce antibiotic resistant bacteria development risks.