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Fluid Journal : Spring 2011
13 The Fluid Journal Spring 2011 • Determine if Avail improves root growth in corn • Determine if Nutrisphere influences tissue N concentration, plant biomass, or N uptake. Location results Plant growth. When data were combined across locations there were significant location-by-starter interactions for root ball mass, root ball depth, and stalk diameter. In most cases these significant differences were between one or more of the starter materials and the no- starter treatment (data not shown). Comparisons between the same starter material with and without Avail found significant differences in root mass at both locations in 2007 and differences in stalk diameter at Pamlico07, Beaufort08, and Pasquotank08 (Table 1). There were no significant differences in root ball depth or width between the same starter material with and without the additive. In 2009, no differences were found between the 10-27-0 with or without the additive in any of the plant or root properties measured. Yield. When data were combined across locations there were significant location and fertilizer source main effects on yield. In four of eight site years, starter fertilizer significantly increased grain yield when compared to the untreated check, resulting in a significant yield advantage in using of starter fertilizer with or without Avail. Table 2 shows the impact of starter materials on corn yield, with or without the additive, across the eight site-years tested. In six of the eight years the use of the additive resulted in numerically higher yields. However, only at Guilford07 was this increase significant at the 5% level. When these results were combined across site years, the additive significantly increased yields when compared to the use of the blended fertilizer alone. Because of differences in N rate and application timing, results were combined within years with the exception of locations Guilford08 and Table 1. Measured root and stalk properties from starter treatments with (Yes) and without (No) Avail. Letters in the same row within each root or stalk property indicate significant differences at p = 0.05. Root Properties Stalk Properties Location - Year Depth (in) Width (in) Mass (oz) Diameter (in) NoYesNoYesNoYesNoYes Pamlico -- 07 5.3 6 5.8 6.1 7.5a 8.7b 0.95a 1.0b Currituck -- 07 3.6 3.7 5 5 9.0a 11.2b 0.93 0.95 Beaufort -- 08 2.6 2.6 4 4.3 2.6 2.8 0.74a 0.78b Pasquotank - 08 3.7 3.8 5.8 5.6 4.7 3.8 0.79a 0.83b Hyde -- 09 6.9 7.1 5.2 5.4 3.1 3.2 0.95 0.95 Table 2. Yield results from eight locations across two years comparing treatments with no starter, starter (10-27-0, 12-12-4, or 17-17-0) without Avail, and the same starter treatment with Avail. Different letters within each row indicate locations or overall average where the use of Avail resulted in a significant yield increase compared to the use of the same starter material without Avail at p=0.05. Corn Yield (t ha-1) Location - Year Blended Fertilizer Soil P Level No Starter Starter only Same Starter with Avail Pamilico 07 10-27-0 Med 11.6a 12.1ab 12.8b Currituck 07 10-27-0 Med 12.0a 12.6a 12.6a Davidson07 17-17-0 Med 7.8a 9.1b 8.2ab Guilford07 12-12-4 Low 9.0a 8.9a 10.4b Perquimans07 12-12-4 Low 8.2a 9.1ab 10.1b Pasquotank08 10-27-0 High 10.4a 9.6a 10.1a Beaufort08 10-27-0 High 8.1a 7.7a 8.0a Hyde09 10-27-0 High 14.0a 14.2a 14.0a Average 9.9a 10.5b 11.0c Forsythe08, which were analyzed as a unit due to the fact that they included starter fertilizer treatments with and without Avail. In both 2007 and 2008, the combined analysis found a location-by-rate interaction (p = 0.0022 and 0.0059 in 2007 and 2008, respectively) and a significant rate effect (p < 0.0001 and 0.0055, respectively). In 2008, when N was applied at lay-by, there was significant source effect (p = 0.0067). The addition of Nutrisphere resulted in a significant yield increase of 0.74 t/ ha-1 compared with 30 percent UAN alone (Table 3). While the source-by- rate interaction was not significant in either 2007 or 2008, contrast statements indicated that there were differences in corn yield between 30 percent UAN and 30 percent UAN plus the additive at one or more N rates. In 2009 there were strong location-by-rate (p < 0.0001) and application timing-by- source (p = 0.0124) interactions. When the additive was added to 30 percent UAN and applied at planting there was a significant yield increase of 0.37 t/ ha-1 and contrast statements found a significant yield increase when the additive was applied with 30 percent UAN at an N rate of 101 kg/ha-1 (Table 3). In 2009, no significant yield differences between 30 percent UAN and 30 percent UAN plus the additive were found when the applications were made at lay-by. When Forsythe08 and Guilford08 were combined, statistical analysis found a strong treatment effect (p = 0.0011). Contrast statements were "Root mass was significantly increased." "Corn yield increased in five of eight site years."
Early Spring 2011