MORTALITY-RATES OF FECAL BACTERIA IN SUBSOIL AMENDED WITH POULTRY MANURE

One potential utilization of poultry waste is in the reclamation of su rface mine soil. However little is known about the persistence of feca l bacteria in the buried environments of reclaimed mine soil. A labora tory study was used to determine fecal bacteria mortality during an 8 week incubation in topsoil and subsoil representative of reclaimed sur face mines in western Kentucky. Manure loading rates equivalent to 37. 5 and 75 Mg ha(-1) were used. Manure loading rates had no effect on mo rtality rates. Mortality rates were adequately described by a two-stag e exponential decay model. The rates for the first 2 weeks of incubati on were significantly greater in subsoil than topsoil for total colifo rms (0.31 log(10) cells day(-1) vs 0.20 log(10) cells day(-1)), fecal coliforms (0.33 log(10) cells day(-1) vs 0.22 log(10) cells day(-1)), and fecal streptococci (0.31 log(10) cells day(-1) vs 0.24 log(10) cel ls day(-1)). Bacterial cell numbers decreased to, or close to, detecti on levels (3 colony forming units g(-1) soil) after 8 weeks of incubat ion. Manure application to this subsoil does not appear to be a greate r threat to environmental quality, due to fecal bacteria survival in r eclaimed mine soil, than surface application in the same environment.