Survival and leaching of fecal bacteria after slurry spreading on mountainhay meadows: consequences for the management of water contamination risk

The aim of this work is to achieve a better understanding of the behavior o f fecal coliform populations on the vegetation and in the soil after slurry spreading in environmental conditions, typical of vegetative growth period in mountain hay meadows. Changes in fecal coliform populations on the vege tation and in the soil were monitored in situ for 3 months after slurry spr eading on 9 plots. The variations found in populations are related to the a gricultural, soil. and climatic characteristics of plots and to the moistur e regime of soils. These observations are compared with laboratory experime nts on undisturbed soil microcosms. In absence of water flux, survival dura tions recorded in the laboratory and in the field are of the same order of magnitude. The data enable us to pinpoint the influence of various factors affecting the decline and transfer of fecal bacteria in the plant-soil syst em and consequently to discuss the risk management of water contamination b y agriculture. (C) 2001 Elsevier Science Ltd. All rights reserved.