Interactions of Nitrogen Source and Rate and Weed Removal Timing Relative to Nitrogen Content in Corn and Weeds and Corn Grain Yield

Table 6

Corn grain yield as influenced by the interaction of year, location, N source, and N rate.

Nitrogen		2011		2012
Source	Rate	Clayton	Rocky Mount	Clayton	Rocky Mount
	kg ha^−1	kg ha^−1
Urea ammonium nitrate	68	2,270	5,520	3,680	2,940
Urea ammonium nitrate	135	2,730	7,480	4,710	4,680
Urea ammonium nitrate	202	3,490	6,900	5,260	4,560
Sulfur-coated urea	68	1,810	5,180	3,710	2,050
Sulfur-coated urea	135	3,850	5,460	4,760	3,560
Sulfur-coated urea	202	5,150	8,640	4,150	5,350
Composted poultry litter	68	3,480	5,090	3,420	2,810
Composted poultry litter	135	3,720	5,080	3,510	3,010
Composted poultry litter	202	3,440	5,380	4,230	3,300

Means within a combination of year and location followed by the same letter are not significantly different according to Fisher’s protected LSD test at . Data are pooled over levels of average weed height at timing of removal.