Estimating Nitrogen Availability of Heat-Dried Biosolids
Table 3
Biosolids and urea N fertilizer application amounts and timing for the ten treatments.
Annual application rate (kg ha−1 total N)
Year
N source
Application timing
Application dates
Soundgro
Milorg
Sumner
Zero N Control
Low Urea
Med Urea
High Urea
Trial A
Application Yr 2007
Biosolids
Single (1X)
16 Apr
630
592
907
Biosolids
Split ( appl)
16 Apr, 14 Jun
630
592
907
Urea
Split ( appl)
17 Apr to 20 Jul
0
90
180
270
Residual Yr 2008
Biosolids
Split ( appl)
5 Mar to 8 Aug
168 U*
168 U
168 U
Biosolids
Split ( appl)
5 Mar to 8 Aug
168 U
168 U
168 U
Urea
Split ( appl)
5 Mar to 8 Aug
0
112
224
336
Trial B
Application Yr 2008
Biosolids
Single (1X)
25 Apr
441
414
635
Biosolids
Split ( appl)
25 Apr, 3 Jul
441
414
635
Urea
Split ( appl)
25 Apr to 12 Sep
0
112
224
336
Residual Yr 2009
Biosolids
Split ( appl)
4 Mar to 22 Jul
168 U
168 U
168 U
Biosolids
Split ( appl)
4 Mar to 22 Jul
168 U
168 U
168 U
Urea
Split ( appl)
4 Mar to 22 Jul
0
112
224
336
168 U: In residual yr, 168 kg N ha−1 of urea-N applied to all biosolids treatments, following same urea application schedule as urea the treatment plots.