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Fluid Journal : Fluid Journal 2002-2004
2 Fluid Journal Summer 2002 Responses to variables Placement. Although surface dribble-applied starters had not been as effective as 2 x 2 placed starters the previous two years of the experiment, there was no difference in starter placement methods in 2001. A very wet spring probably increased the efficiency of the surface-banded starter. Grain sorghum tissue nutrient concentrations were not affected by starter application method. When averaged over the period 1999-2001, yield of 2 x 2 placed starters was only 6 bu/A greater than the surface-dribble treatment (Figures 1 and 2). Fertilizer. The greatest yields occurred with applications of starters containing either 30 or 45 lbs/A of N with 30 lbs/A of P2O5. Higher N starters were the most efficient in reducing the number of days from emergence to mid- bloom. N alone or P alone did not yield as well as starters that contained both N and P. Treatments containing only 15 lbs/A of N with 30 lbs/A of P2O5 also were not as effective as starters containing more N. The starters containing either 30 or 45 lbs/A of N with 30 lbs/A of P2O5 resulted in the greatest V-6 stage whole plant dry matter accumulation. Tissue P concentrations increased with increasing amounts of N in the starter. Starter vs. check. All starter treatments increased grain sorghum yield over the no-starter check plots. All starter treatments increased V-6 stage whole plant dry matter over the no-starter check. Grain moisture in the 30-30 starter treatment was lower at all sample dates compared to the no-starter 10 15 20 25 30 35 SEPT. 8 SEPT. 14 SEPT. 22 SEPT. 30 OCT. 6 OCT. 12 % grain moisture 0-0 30-30 0-30 15-30 Figure 3. Effect of NP starter fertilizer composition on grain moisture dry-down for a 2 x 2 placement (values averaged over tillage system), Gordon & Whitney,Belleville, 2001. check, as well as the P alone treatment, or the one that included only 15 lbs/A of N (Figure 3). Tillage. Use of starters resulted in greater yields in both tillage systems. Grain yield, days from emergence to mid-bloom, and V-6 stage whole plant dry matter were not affected by tillage system. Grain sorghum tissue nutrient concentrations were not affected by tillage. Methodology Soil. The experiment was conducted at the North Central Kansas Experiment Field on a Crete silt loam soil. Analysis by the KSU Soil Testing Lab showed that initial soil pH was 6.2, organic matter was 2.2 percent, Bray P- 1 was 45 ppm, and exchangeable K was 320 ppm in the top 6 inches of soil. Tillage systems were minimum- and no-till. The minimum-till system received one disking and harrowing operation in the spring, three weeks prior to planting. Placement. Starters were placed at planting either 2 inches to the side and 2 inches below the seed or dribbled in a band on the soil surface 2 inches beside the seed. Fertilizers. Starters consisted of N and P2O5 combinations giving 15, 30, or 45 lbs/A of N with 30 lbs/A of P2O5. Also included were treatments consisting of 1) either 30 lbs/A of N or 30 lbs/A of P2O5 applied alone, and 2) a no-starter check. Starter combinations were made by using 10-34-0 and 28% UAN. After planting, knife applications of 28% UAN were made to bring N applied on each plot to a total of 140 lbs/A. Planting. Grain sorghum (NC+7R83) was planted at the rate of 60,000 seeds/A on May 22, 2001. Harvest. Plots were harvested on October 12, 2001. Dr. Gordon is professor and Dr. Whitney is professor in the Department of Agronomy at Kansas State University.
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