|Blank, Robert - Bob|
Submitted to: Journal of Range Management
Publication Type: Review Article
Publication Acceptance Date: 8/1/2002
Publication Date: 7/1/2003
Citation: Blank, R.R., Chambers, J., Zamudio, D. 2003. Prescribed burning of central Nevada degraded riparian ecosystems: effects on soil and vegetation. Journal of Range Management. 56(4): 388-396. Interpretive Summary: To facilitate species diversity and increase herbaceous forage production, techniques are needed to restore degraded riparian ecosystem. We evaluated prescribed burning as a tool to restore degraded riparian ecosystems in central Nevada. Relative to unburned controls, prescribed burning decreased surface soil activities of several enzymes, reduced the surface soil content of C and N, and increased plant available pools of S, Ca, Mg, and K. Some plants establishing after the prescribed burn utilize the fire-released soil nutrients and accumulate more biomass than paired plants in control sites. Although limited time has past, it appears that prescribed burning of degraded big sagebrush along riparian corridors increases herbaceous plant production and plant diversity.
Technical Abstract: Over much of the western United States, stream incision has resulted in lowered water tables and encroachment of sagebrush into riparian areas formerly dominated by meadow ecosystems. Prescribed burning was evaluated as mechanism to restore dry meadows. We studied the influence of fall (Oct. 1996) prescribed burning on soil enzyme activities, total soil C and N, extractable soil nutrients, and post-fire vegetation recruitment, growth, and nutrient content. As compared to unburned controls, prescribed burning: i) increased aaqueous-extractable SO4-2, K+, and KCI-extractable NH4+, ii) decreased activities of the enzymes asparaginase, urease and acid-phosphatase, and iii) decreased KCI-extractable NO3- and ortho-P. The depth of influence was largely limited to 5cm. Per unit area biomass of Lupinus argenteus (three years following the prescribed burned) was significantly greater on a prescribed burned site compared to its unburned control; while per unit area of Carex douglasii increased only on burned subcanopies. Tissue concentrations of macro-nutrients were generally far less for plants growing on the prescribed burned plot than on the control plot. Greater vegetative growth on prescribed burned plots may be explained by a combination of enhanced late season soil water availability and reduced competition from sagebrush.