The microorganisms concerned with a higher ratio of biological nitrogen turnover in upland field soils applied with large amounts of raw liquid livestock feces were searched for using a newly developed genetic analysis system and method. In upland field soils, the flora of proteolytic bacteria, denitrifying bacteria, and bacteria isolated on peptone-polymyxin medium changed in relation to the amount of the applied liquid feces (120 t ha^-1 y^-1 and 600 t ha^-1 y^-1). The isolated proteolytic Serratia marcescens, denitrifying Salmonella/E. coli, and non-Bacillus polymyxin B-resistant bacteria were non- indigenous soil bacteria typically found in the soil applied with raw feces, and their numbers were estimated to be over 10⁵ CFU g^-1 dry soil after 2 months of the application. They were supposed to have contaminated the field soils from bacteria present in the raw feces that survived for a while in the fields.