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Fluid Journal : Fluid Journal 1993-1995
Dr. Richard H. Fox and William P. Piekielek Fl uids Shine in Ammonia V Fl uids Shine in Ammonia V Fluids Shine in Ammonia V Fluids Shine in Ammonia V Fluids Shine in Ammonia Volatilization olatilization olatilization olatilization olatilization Comparisons Comparisons Comparisons Comparisons Comparisons Testsin no-till corn fieldsin centralPennsylvania compare UAN with urea. Summary: In 1992, we initiated a field experi- ment to determine if a new, simplified microme- teorological method could be used to measure ammonia volatilization losses from surface- applied urea-containing fertilizers. The measur- ing devices were rotating ammonia samplers set at one height in the center of large circular plots. Losses from these fertilizer sources were checked against losses measured by comparing yields and N uptakes from treatments receiving different sources and/or methods of application. In 1993, measurement of the volatilization losses by the samplers was much more precise. Ammonia volatilization loss over a 16-day period, afier application of 120 lbs/A broadcast uWinter 1994rea-N applied to no-till corn, was 26 to 29 lbs/A. This was signi-ficantly more than the approximately 13 to 15 lbs/A lost from dribbled UAN. The loss from sprayed UAN was 20 lbs/A, which was signifi-cantly less than from urea when outlier plots were eliminated. There were no significant differences in yields or N uptakes among the N source/ method treatments, which substantiates the increased precision in estimating ammonia volatilization loss when using the simplified micrometeorological ammonia sampler. Spring 1994 With recent emphasis on converting to no-till agriculture in order to in- crease organic C levels and reduce the rate of increase in atmospheric CO2 concentration, the need to understand factors controlling ammonia volatiliza- tion loss from surface-applied urea- containing fertilizers has intensified. This article reports on studies examin- ing a simplified micrometeorological approach to measuring ammonia volatilization losses from two urea sources, using different placement methods. Including outlier plots There was a total of 7 to 16.6 lbs/A of N as ammonia trapped in the background samplers over a 16-day sampling period. When the back- ground value for the individual replica- tion was subtracted from the ammonia- N in each of the treatment samplers, total amount of volatilized ammonia over the 16-day period ranged from 15 to 29 lbs/A of N. The least loss was from dribbled UAN and the most from broadcast urea (Figure 1). Ammonia loss from the 120 lbs/A of N applied ranged from 13 percent for dribbled UAN to 24 percent for broadcast urea. Loss from urea was less and losses from UAN treatments were about the same as observed in 1992. Measuring total amount of ammonia N volatilized among 1993 treatments showed loss from broadcast urea was significantly greater than losses from dribbled UAN. However, since most of the loss in the broadcast treatments occurred in the first week, there were no significant 30 25 20 15 10 5 Urea Broadcast lbs/A Figure 2. Total ammonia loss over 16- day period using different sources/methods, elinimating two outlier plots, Fox and Piekielek, Penn State, 1993. UAN Spray UAN Dribble 30 25 20 15 10 5 Urea Broadcast lbs/A Figure 1. Total ammonia loss over 16- day period using different sources/methods, with outlier plots, Fox and Piekielek, Penn State, 1993. UAN Spray UAN Dribble 120 115 110 105 100 Urea Broadcast Yield (bu./A) Figure 3. Corn Yields at early dent stage as function of N fertilizer source and method of application, Fox and Piekielek, Penn State, 1993. UAN Spray UAN Dribble
Fluid Journal 1996-1998