Microbial communities in the phyllosphere of grasses on fenland at different intensities of management

Abstract

The effects of changes from conventional grassland management on fenland in Germany to extensification due to reduced fertilizer inputs and cutting frequency on the microbial colonization in the phyllosphere were investigated. A delay in the first cut for silage and hay, required by a nature conservation programme, was accompanied by the senescence of grasses which significantly influenced certain microbial groups. Heterotrophic bacteria, aerobic and anaerobic spore-formers, as well as filamentous fungi, showed an increase in population densities on the mature herbage of the later cuts. Differences in the rate of fertilizer application and cutting frequency, which had an effect on the dry-matter yield, also influenced the population density of heterotrophic bacteria and, in certain circumstances, that of filamentous fungi. Chemical measures of forage quality were highly correlated with the population density of microbial groups and with the maturity of the herbage. In contrast to these results, the population dynamics of further groups of micro-organisms (yeasts, Micrococcaceae, listeria) did not show any relationship with pasture management.