Dryland Winter Wheat Yield, Grain Protein, and Soil Nitrogen Responses to Fertilizer and Biosolids Applications
Table 2
Biosolids total N, ammonium (NH4)–N, solids content and material, and N application rates for each site-year. Soundgro and Tacoma are two biosolids products produced in the Seattle, Washington metropolitan area.
Year
Site
Biosolids origin
Total N
NH4–N
Solids
Rate code
Dry application rate
Total N
Estimated available N†
Plant-available N
%
%
%
Mg ha−1
kg ha−1
% of total N
Kg ha−1
2006
Lind
Soundgro
5.80
0.53
93.3
1×
4.4
257
50
129
5.80
0.53
93.3
2×
8.8
508
50
254
Davenport
Soundgro
5.85
0.56
91.6
1×
5.4
314
50
157
5.85
0.56
91.6
2×
10.9
635
50
317
Pullman
Tacoma
4.60
0.78
21.5
1×
6.4
295
25
74
4.60
0.78
21.5
2×
12.9
591
25
148
2007
Lind
Tacoma
4.90
0.40
22.5
1×
5.0
247
25
62
4.90
0.40
22.5
2×
10.1
494
25
123
Wilke
Soundgro
6.10
0.29
93.6
1×
5.5
334
50
167
6.10
0.29
93.6
2×
11.1
676
50
338
Pullman
Soundgro
6.10
0.29
93.6
1×
6.5
398
50
199
6.10
0.29
93.6
2×
13.0
796
50
398
†Available N estimate is 25% total N for Tacoma product and 50% total N for Soundgro based on Sullivan et al. [3] and Cogger et al. [11].
