PARENT SESSION
Oral Session #59: Soil Ecology: Microbial and Invertebrate.
Presiding: M. Rillig
Wednesday, August 7. 8:00 AM to 11:30 AM. Palo Verde Room, Radisson.
Plant diversity and the soil environment.
Porazinska, Dorota*,1, Six, Johan1, Wall, Diana1, 1 Colorado State University, Fort Collins, CO
ABSTRACT- Plant diversity reflects on the structure of aboveground communities and ecosystem processes and similar patterns might apply to belowground ecosystems. We investigated this relationship over a short time (a mesocosm) and long-time (a natural grassland) periods on soils from the Konza tall grass prairie. Two most dominant grass species (Andropogon gerardii and A. scoparius) were used for 4 experimental treatments: A. gerardii only, A. scoparius only, a mixture of both plant species, and no plants. For mesocosms, soil brought from Konza LTER was sieved, homogenized, and placed in pots in a greenhouse. Seedlings of grasses were planted in the spring, and pots destructively sampled in the summer and fall. The same experimental treatments were sought in a natural setting within the Konza grassland. Microbial biomass and protozoa were not affected by the treatments. Densities of 8 (out of 45) nematode genera were affected by the treatments, but consistent patterns across short and long time effects were observed only for plant parasitic Helicotylenchus spp. with densities higher under A. gerardii than other treatments (P ≤ 0.05). Densities of other affected nematode genera were opposite for mesocosm and field settings. Diversity of nematodes and protozoa were not affected by the plant treatments. We also examined root characteristics, soil moisture, total carbon and nitrogen, and the distribution of soil pores and aggregates. The results indicate idiosyncratic responses of belowground components to plant diversity.
KEY WORDS: plant diversity, soil biota, soil C and N, soil pores and aggregates