63 Using PRS™-probes to investigate how ecosystems function under invasive plant species and nitrogen dynamics

Tuesday, August 4, 2009
Exhibit Hall NE & SE, Albuquerque Convention Center
Elaine J. Qualtiere , Western Ag Innovations, Saskatoon, Canada
Rebekka Rieder , Western Ag Innovations, Saskatoon, Canada
Dana Blumenthal , USDA-ARS, Ft. Collins, CO
Edward Vasquez , Eastern Oregon Agricultural Research Center, USDA-ARS, Burns, OR
Roger L. Sheley , USDA-ARS Eastern Oregon Agricultural Research Center, Burns, OR
Tony Svejcar , USDA, Agricultural Research Service, Burns, OR
Brady W. Allred , Oklahoma State University, Stillwater, OK
Keirith Snyder , USDA, Agricultural Research Service, Reno, NV
Background/Question/Methods

Natural ecosystems are in a state of constant fluctuation.  However, most exist as a climax community represented by vegetation types based on soil, climate and other anthropogenic factors.  These systems normally have tight nutrient cycling, with few nutrients in free abundance.  Currently, many natural ecosystems are being negatively affected by invasive species, climate change, disturbances, and human actives. These forces are changing the inherent soil supply rates, causing altered nutrient cycles.  Plant Root Simulator (PRS) ™-probes were used in a number of grassland ecosystems to study the effects of fire, plant invasion and nitrogen immobilization on soil nutrients flux. 

Results/Conclusions

Allred and Snyder (2008) used PRS™-probes to prove that fire increased the soil’s bioavailable nitrogen supply.  This introduced a potential competitive advantage to native species and may help to remediate shrub encroachment.  Blumenthal (2008) demonstrated that carbon additions can increase nitrogen immobilization and lead to a reduction of total plant biomass and the invasive ability of non-native species.  Additions of nitrogen fertilizer increased the supply rate of nitrate in grassland soils, allowing cheatgrass (Bromus tectorum) to accumulate a greater proportion of biomass and out-compete native grasses (Vasquez et al., 2008).  These studies demonstrate how PRS™-probes can be used to examine the effects of these forces on ecosystems across the globe from a plant’s perspective, and can answer a multitude of ecological questions facing society today.  These studies highlight how PRS™-probes can help manage and create sustainable ecosystems, by bridging the gap between plants and the soil in which they grow.

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