Fungal community structure in soils of conventional and organic farming systems

Analysis of soil microbiota may help to describe and understand effects of agricultural management on soil quality. In the present study, effects on soil fungal communities were analysed in the DOK long-term agricultural field experiment in Switzerland. The temporally shifted 7-yr crop rotation allowed evaluation of the temporal stability of effects of organic and conventional farming systems. The influence of farming systems, crops and time on soil fungal community structures was compared between 2000 and 2007 using ribosomal internal spacer analysis. Richness of the fungal communities remained largely stable at the two different sampling dates, whereas the abundance of individual components changed. Despite this temporal stability, the most pronounced difference in the fungal communities was between the two sampling time points, whereas the influence of crops and farming systems were smaller. The time effect may be mainly induced by system-independent factors including changes in climatic conditions but also by system-dependent factors such as changes in preceding crops and farmyard manure characteristics between 2000 and 2007.