Interactions of Nitrogen Source and Rate and Weed Removal Timing Relative to Nitrogen Content in Corn and Weeds and Corn Grain Yield
Table 4
Nitrogen content in corn plants when weeds were removed at a height of 8 cm compared with weed-free corn as a result of the interaction of environment, N source, and N rate.
Nitrogen content in corn plants
Average weed height at timing of removal (cm)
Nitrogen
2011
2012
Clayton
Rocky Mount
Clayton
Rocky Mount
Source
Rate
0
8
0
8
0
8
0
8
kg ha−1
kg ha−1
Urea ammonium nitrate
68
2.3
2.2
0
5.1
2.3
3.6
3.8
2.9
Urea ammonium nitrate
135
6.1
3.2
10.0
5.2
4.2
4.6
4.6
4.4
Urea ammonium nitrate
202
3.9
4.3
8.5
5.4
2.9
2.6
2.0
3.9
Sulfur-coated urea
68
3.7
2.2
10.6
6.7
3.6
2.1
2.4
2.2
Sulfur-coated urea
135
4.7
2.8
4.0
5.8
2.9
4.2
2.6
3.3
Sulfur-coated urea
202
7.8
2.55
12.5
6.4
1.7
2.9
4.5
3.8
Composted poultry litter
68
3.7
2.4
8.7
4.9
2.9
1.6
4.0
2.5
Composted poultry litter
135
3.6
2.6
9.7
5.2
3.5
4.1
5.2
4.3
Composted poultry litter
202
3.7
2.5
7.6
5.5
4.3
4.0
4.9
4.2
Means within a year and location followed by the same letter are not significantly different according to Fisher’s protected LSD test at .
