Document: LOU-3-58-39

Feedbacks between plant and soil commmunities.

INNES, L.* and R.DBARDGETT

Lancaster University, Lancaster, Lancashire LA1 4YQ United Kingdom ¹

Abstract:
There is presently much interest in the effects of individual plant species on soil microbial communities, and understanding how these interactions feedback in terms of above-ground productivity and plant community structure. The aim of this study was to examine how individual plant species (Lolium perenne, Anthoxanthum odoratum, Holcus lanatus, Achillea millefolium, Trifolium pratense, Plantago lanceolata), which dominate the flora of UK herb rich haymeadows, influenced soil biota and competitive interactions between plants. Using microcosms, plant species effects on two soils of differing soil N status were investigated through a range of plant (shoot and root biomass ratios) and microbial (microbial biomass carbon, activity and community structure)measurements. Results showed that plant species significantly affected soil microbial biomass C and activity at both N levels. Results were expressed as percentage difference relative to bare soil. Lolium perenne, a dominant grass of high fertility grasslands negatively affected microbial biomass C and activity in the low N soil (-14 and -1% respectively). Holcus lanatus, a grass of intermediate fertility grasslands, positively (+24%) and negatively (-9%) affected microbial biomass c in the high and low N soils respectively. This species showed positive effects on microbial activity in both soils (11.5% low N and 5.4% high N). Anthoxanthum odoratum also exhibited postive (+16.2%) and negative (-12.6%) effects on microbial biomass C in the high and low N soils respectively. The three dicot species negatively affected microbial biomass C and activity in the two soils. This study shows that there are significant plant species effects on the soil microbial biomass at different N levels. Such plant species effects have important implications for plant community structure and nutrient cycling through competitive feedback effects.

Keywords: Plant species effects

This abstract is being presented at: 10:45 AM in session:
Oral Session #23: Soil Ecology.