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Recovery of Nitrogen Pools and Processes in Degraded Riparian Zones in the Southern Appalachians
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Impact/Purpose:
Journal article
Description:
Soil nitrogen (N) cycling mechanisms were examined over a 4-year period in a restored mountain pasture riparian zone previously degraded by cattle. Chemical and physical effects of grazing were separated by comparing the following treatments: (1) a degraded riparian area with continued compaction, vegetation removal, and nutrient addition (+N); (2) a degraded riparian area with continued compaction and vegetation removal, but without nutrient addition (-N); and (3) a restored riparian area with regrowing vegetation, no compaction and no nutrient addition (-N). Our results show that the restored riparian zone reduced above and belowground fluxes of inorganic nitrogen to the adjacent stream. Soil solution nitrogen oxide concentrations at 30 and 90 cm depths in the restored areas were 99% and 97% lower, respectively, than concentrations in the degraded (+N) treatment. Total inorganic N concentration and volume of overland flow exiting the restored treatment were 63% and 93% lower than overland flow exiting the degraded (+N) treatments. s a pathway by which N is diverted from the receiving stream to the atmosphere. Our results indicate that changes in soil nutrient cycling mechanisms following cattle exclusion from degraded riparian areas are primarily driven by cessation of N inputs. The rate of riparian zone recovery, however, appears to be influenced by rates of vegetation regrowth and soil compaction reversal.
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RECOVERY OF NITROGEN POOLS AND PROCESSES IN DEGRADED RIPARIAN ZONES IN THE SOUTHERN APPALACHIANS
NRMRL RTP P 1005.PDF (PDF, NA pp, 2049 KB, about PDF)