The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Wednesday, January 30, 2008
46
Defoliation Impacts on above and Belowground Production in A Riparian Sedge Community
Chad S. Boyd and Tony J. Svejcar. USDA-ARS Eastern Oregon Agricultural Resarch Center, 67826-A Highway 205, Burns, OR 97720
In spite of the interest in grazing impacts on riparian systems, there is limited information on root response of riparian species to grazing. We evaluated both aboveground and belowground productivity in plots clipped in either June or July to a 10 cm stubble height. The study was designed as a randomized block with 4 replications and conducted during 2004 and 2005. The first year had near average precipitation and 2005 was slightly above average. Root ingrowth tubes were used to harvest annual root growth, and 50 x 20 cm plots were clipped to estimate aboveground end-of-season standing crop. Both clipping treatments reduced end-of-season standing crop (p < 0.05), but season-long production (clipped mass + end-of-season mass) was less impacted by clipping treatment. Root mass was significantly (p < 0.05) reduced by only the July 2005 clipping treatment, and root length density was not significantly impacted by any treatment (p > 0.05). Root mass and length appear more resilient to clipping treatments than aboveground production and end-of-season standing crop.