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Fluid Journal : Fluid Journal 1993-1995
2 Fluid Journal Fall 1995 assess their availability with soil tests. The probability of contacting bands with standard soil sample procedures depends on the amount of soil affected by applied P. While results do not allow accurate calculations of hand size for times other than 94 days, the probability of contacting these bands with standard soil-sampling procedures is quite high. Not only is the probability of contacting these P bands at soil sampling great, but the residual nature of these bands for plant uptake also could be substantial. Further research is needed to evaluate the residual nature of these bands and how soil sampling and soil test calibration can he altered to account for the residual effects of banding. Fluids used Fertilizer and rate. A 4-inch long band of APP (10-34-0) was injected into the soil at a depth of 2 inches. Application rates were 30, 46, 61, 77, 92, and 123 lbs/A of P2O5 with a band spacing of 12 inches. P was allowed to diffuse under field conditions on bare soil during the summer of 1986. Precipitation during the 94 days was 13.8 inches. Soils. The top 6 inches of Coly silt loam and Nora silt loam were collected from small patches of fields in Sherman and Boone Counties in Nebraska, respectively. The top 12 inches of a Sharpsburg silty clay loam soil was removed at the Agricultural Research and Development Center at Mead, Nebraska. Open boxes 12 inches deep were placed in the removed area and filled with Coly and Nora soils. Sharpsburg soil was used alongside of the boxes. Dr. Eghball is assistant professor, Dr. Sander is professor, and Dr. Skopp is associate professor in the Department of Agronomy at the University of Nebraska. ! Figure 1. Apparent diffusion distances of banded P at different P rates in three soils, Eghball, et al., University of Nebraska, 1986. 3046617792123 30466177921233046617792123 P2O5 rate - lbs/A MEAN: 0.9 P diffusion - inches MEAN: 1.10 MEAN: 0.94 Coly Nora Sharpsbu rg 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 3046617792123 30466177921233046617792123 P2O5 rate - lbs/A MEAN: 5.6 P Longevity - years MEAN: 4.1 MEAN: 3.3 Coly Nora Sharpsbu rg 8 7 6 5 4 3 2 Figure 2. Apparent longevity of banded P at different P rate in three soils, Eghball, et al., University of Nebraska, 1986.
Fluid Journal 1996-1998