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Fluid Journal : Fluid Journal 2005-2007
Winter 2006 Banded P Increases Sugarbeet Yields Drs. Jason Ellsworth and Bryan Hopkins Summary: One location (Rockford) showed significant responses to treatments, with APP at three depths and the surface and 3-inch deep UAN producing significant increases in sugarbeet tonnage. However, only surface UAN and the 6-inch deep APP bands resulted in significantly increased sugar production when sugar percentage was combined with tonnage. Although some inconsistencies exist between locations over the years of the study, the APP band at the 6-inch depth resulted in the highest total sugar production for three of the five site years of data. Shallower placement (3-inch) or surface banding also resulted in increased yields in a previous study, but the effect was neither as great nor as consistent as the deep-banded treatment when evaluating the findings of this study over three years. In general, starter UAN bands did not enhance sugar production, although a significant increase in sugar yield was observed at one site in 2004 with surface band-applied UAN. Although additional studies are planned, the Idaho studies show deep-banded APP produced the most significant increases in sugarbeet production. Fluid Journal 1 Studies in the North-Central U.S. in 2001 showed yield increases with the use of 12 to 20 lbs/A of P2O5 as ammonium polyphosphate (APP, 10-34-0) starter in sugarbeets. Researchers found increased yields when a starter band was placed: 1) in direct seed contact, 2) two inches below the seed, and 3) two inches below and two inches to the side of the seed. The magnitude of the response, however, was delayed and reduced as the distance between the seed and the starter fertilizer band increased. Researchers concluded that direct seed contact was the best option due to the rapid, vigorous response and because much of the soil in which the sugarbeets are being grown in that region is high in clay and susceptible to implement/soil interface compaction, thus creating a poor seed bed. Other research also supports the fact that optimal placement of phosphorus (P) for sugarbeets seems to be directly below the seed. Idaho studies have shown that banded P may enhance subsurface P uptake if placed relatively deep in the path of the sugarbeet tap root. The initial objective of the project reported in this article, therefore, was to determine if deep-banded P enhances sugarbeet P nutrition and, if so, how does this impact final yield and sugar content? In the first year (2002) of this project, banded applications of APP resulted in increased sugarbeet yield, regardless of rate or placement depth. Broadcast and banded phosphoric acid (PA) applications did not increase sugarbeet yield. Percent sugar content was not significantly different for any treatment. However, when combined with yield to calculate sugar production, the deep- banded (6-inch) APP treatments generally resulted in increased sugar production. Surface and 2-inch starter bands of APP also resulted in increased sugar yield, but the differences were not statistically significant from the check. Surprisingly, the PA treatments did not result in an increase in sugar yield, which leaves the reasoning for the response of the APP in doubt. Was the results of this study, in combination with the work from previous years, show that deep banding P on sugarbeets enhances P uptake and, as a result, sugar production. Figure 1. Sugarbeet N and P placement effect on sugar yield for the Minidoka location, 2004. Figure 2. Sugarbeet N and P placement effect on sugar percent for the Rockford location, 2004.
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