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Fluid Journal : Fluid Journal 2005-2007
No other starter treatment significantly increased yield over the pop-up treatment. Grain yield was increased (P=10%level)bythe20+20+10+10 treatmentoverthe20+20+6+0 treatment when averaged across placement positions. Placement position did not affect grain yield. Grain moisture Grain moisture at harvest was affected significantly by starter fertilizer (Table 3). Grain moisture was highest (27.3%) for the no-starter control and lowest (22.7%)forthe6+20+6+4pop-up treatment. This 4.6-point advantage for the pop-up starter fertilizer can translate into a substantial saving in drying costs. Currently, drying costs about $0.03/point or 14 cents/bu in this case, which, assuming 190 bu/A, is a savings of $26.60/A. Grain moisture was higher (27.4%) when S was omitted (20 + 20 + 6 + 0) compared to including S in 20 + 20 +6+4(24.3%)or20+20+10+10 (24.7%) when averaged across starter treatment rates. Placement position had no affect on grain moisture. Plant population Initial plant population was not Early Spring 2006 Fluid Journal 3 affected by any of the starter fertilizer treatments, indicating no phytotoxicity for the starter rates or placements under the wetter conditions immediately following planting. Placement of a 4-lb/A S rate in the furrow with the seed may be a concern, however, if drier conditions occurred. Although final plant populations were statistically different among the 12 treatments, the range from 32,400 to 33,100 plants/A and the CV (0.7%) were very small. Conclusions Plant growth. In this cool spring when wet conditions prevailed after planting, a significant plant growth response was recorded for all but one of the starter fertilizer treatments on this very high P-testing soil. Greatest growth (138% larger than the control) wasobtainedwiththe6+20+6+4 pop-up treatment. Concentrations of NPKS were not greatly different among any of the treatments at the V6 stage. However, uptake of NPKS was greatly affected by starter fertilizer due to the large effect of starter fertilizer on early growth. Yield. Corn grain yields increased an average of 17 bu/A (5 to 29 bu/A) by the starter fertilizer treatments over the no-starter control (182 bu/A). None of the higher rate NPKS treatments increased yield significantly over the 6+20+6+4pop-uptreatment(199bu/ A). Yield tended to be consistently greater when S was included in the starter treatment. The wet and cool conditions may have limited mineralization of S from the organic matter and, combined with very high yields, resulted in the response to S. Grain yields were not different between the surface dribble (2-inch x 0) and injected (2-inch by 2-inch) placements. Grain moisture at harvest was significantly reduced by some of the starter fertilizer treatments, especially the pop-up treatment. These reductions in grain moisture due to starter fertilizer could reduce drying costs by up to $27/A and should be strongly considered when making decisions regarding whether to use starter fertilizer --- even on soils testing 28 ppm P (very high) based on this single year of data. Dr. Randall is soil scientist/professor and Vetsch is assistant scientist at the Southern Research & Outreach Center, University of Minnesota.
Fluid Journal 2002-2004
Fluid Journal 2008-2009