ARS | Publication request: Characterization of soil microbial community dynamics related to C and P cycling along a forest to pasture gradient

Submitted to: North America Forest Soils Conference
Publication Type: Proceedings
Publication Acceptance Date: December 21, 2007
Publication Date: N/A

Technical Abstract: In the Appalachian Mountains region landscape fragmentation due to farming practices results in areas with gradual blending of forests and pastures ecosystems. Soil nutrient cycling in the open land-forest boundary may be significantly different than in the forest soil or in the pasture soil and this may have implications for pasture as well as for forest management. Also, information on the size of this edge and its effect on microbial communities are scarce. The objective of this study was to determine the zone of influence of the trees in the pasture soil microbial communities by determining the extent of the spatial scale at which the forest microbial signature transitions into the pasture microbial signature. Here, we present data from a gradient study were soil samples were collected along an 80 m transect from an Appalachian hardwoods forested area into a pasture area. We characterized the soil bacterial and fungal community structure and function, which we draw on as indicators of nutrient cycling dynamics, using DNA-based molecular methods and community level physiological profiles. Data on enzymes activities involved in C and P cycling is also presented. Also, the influence of an individual tree on the above parameters is discussed. This knowledge will contribute to the design and implementation of better management practices in fragmented or mixed land cover systems. Understanding the effects of these landscapes constructs in soil nutrient cycling may also be relevant for management of silvopastoral systems.