Nitrogen Deposition Study: Fertilizer Treatment Descriptions
In use from 2001-01-01
Fertilized (F) plots are 100 m2 (10m x 10m) each, except in CF3, where the fertilized plot is 6m2(2m x 3m). Annual application rate is 10 kg Nitrogen (N) ha-1 as Ammonium nitrate (NH4NO3), equivalent to 100 g (6 g on CF3) N per plot. The N is added in 3 doses. Each time 16 L (4 L on CF3) of fertilizer solution are added per plot. The 3 doses are applied in the period April thru November (after spring thaw thru litterfall).
Three-fold fertilization (3F) plots are 4m2 (2m x 2m) each. The annual application rate is 30 kg N ha-1 added in 4 L per plot solutions.
Added in 2007, ten-fold fertilization (10F) plots are 4m2 (2m x 2m) each and only in the DF treatment. The annual application rate is 100 kg N ha-1 added in 4 L per plot solutions.
Preparing the fertilization solutions
- Weigh 8 bags of 98 g NH4NO3 (34% N) for 1F, 1 bag of 5.88 g NH4NO3 (34% N) for 1F in CF3, and 9 bags of 11.8 g in NH4NO3 (34% N) for 3F.
- Mix fertilizer with RO water in 4L flasks with stir bars on stir plate. Add fertilizer slowly to allow it to dissolve.
- Pour solutions into 4L or 16L sprayers and carboys for spraying or transport to the field.
- Fill the containers for 1F plots to 16L and the containers for CF3-1F and all 3F plots to 4L.
Spraying the plots
- Use a 16L backpack sprayer to apply the fertilizer solutions to the 1F plots and a 4L hand sprayer for the 3F plots and 1F in CF3.
- Divide the 1F plots into quadrants and apply 4 liters of solution to each.
- In the 3F plots, apply the 4 liters of solution evenly across the plot.
Ammonium nitrate was not available in 8/2003, 10/2006, 4/2007, 6/2009 and 9/2011. Urea (46% N) was used for fertilizing at the same rates of N. The 1F plots had 72.44 g Urea applied, except CF3 received 4.35 g Urea. The 3F plots received 8.72 g Urea/application.
From 2001 through 2008, an erroneous fertilizer level was applied at 10 times the appropriate level. So, during those years the 1F plot received nitrogen at a rate of 100 kg/ha/yr, 3F received 300 kg/ha/yr, and 10F received 1000 kg/ha/yr.