Previous studies showed that soil pH was critical to the survival of inoculated bacteria in soil[6,10]. Soil pH showed positive
effects onE. coliO157:H7 survival in original soils, while it was
negative in 20 fertilizer-amended soils.E. coliO157:H7, which is
mainly an intestinal parasite of ruminants, seems to be tolerant
to acidic conditions[27]. However, soil acidic conditions inhibited
theE. coliO157:H7 survival to a great extent in our study (Figs. 1
and 2). Similarly, the effect of pH on the bacterial inactivation in
aquifers is obvious in acidic conditions but negligible at pH levels
between 6 and 8[28,29]. Compared with enteric conditions, most
soil and water environments are relatively oligotrophic and complex, so the sensitivity ofE. coliO157:H7 to acidic conditions in
natural environments are associated with other factors. The hierarchical partitioning also confirmed that the joint contribution of
soil pH was higher in the original soils than in organic-fertilizer
soils (Fig. 3). The different functions of soil pH in this study were
mainly related to soil minerals and organic matter