Nitrogen Deposition Study: Fertilizer Treatment Descriptions

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In use from 2001-01-01

Abstract

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.

Protocol

Preparing the fertilization solutions

  1. 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.
  2. Mix fertilizer with RO water in 4L flasks with stir bars on stir plate. Add fertilizer slowly to allow it to dissolve.
  3. Pour solutions into 4L or 16L sprayers and carboys for spraying or transport to the field.
  4. Fill the containers for 1F plots to 16L and the containers for CF3-1F and all 3F plots to 4L.

Spraying the plots

  1. 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.
  2. Divide the 1F plots into quadrants and apply 4 liters of solution to each.
  3. In the 3F plots, apply the 4 liters of solution evenly across the plot.

Exceptions

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.

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