Tracing the Fate of Applied 15 N Fertilizers in Douglas-fir Plantations Stephani Michelsen-Correa, Betsy Vance, and Rob Harrison University of Washington, School of Environmental and Forest Science. Background:
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Stephani Michelsen-Correa, Betsy Vance, and Rob Harrison
University of Washington, School of Environmental and Forest Science
% of Applied Nitrogen retained by target trees
Figure 1: Differences in the efficiency of Nitrogen fertilizer uptake between pot/greenhouse studies and actual field experiments1 2.
Figure 2: 10 sites along the Western Douglas-fir region of Oregon and Washington
100m2 plot boundary
-224 kg N ha-1
Litter and Soil Sample
Urea + NBPT
Urea + CUF
Figure 4: Concentrations of the fertilizer label in the 2011 foliage from 0-34 weeks after treatment. Urea, NBPT, and CUF follow a similar trajectory through week 10. However, by week 16 urea had the highest concentrations followed by NBPT and CUF respectively.
Figure 5: Concentrations of 15N with mineral soil depth one year after fertilization. This is preliminary data as it represents the concentrations from only one of our study sites.