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Developing Extension guidance for management effects on ammonia loss: a computer simulation modeling approach Public Deposited

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  • Computer simulation models provide insight into ammonia loss processes and the sensitivity of ammonia loss predictions to environmental and management variables. As an example of how a simple computer simulation model can inform the Extension guideline development process, the ALFAM (Ammonia Volatilization from Field-Applied Animal Slurry) model was used to estimate NH3 loss from surface-applied municipal biosolids: liquid (3% dry matter) and dewatered (22% dry matter). Model output was useful in demonstrating the probable effect of environmental variables (wind speed and temperature) upon NH3 loss rate, and the impact of biosolids dry matter NH3 loss dynamics. Using moderate inputs for temperature (10 and 20 oC; 50 and 68 oF) and wind speed (1 and 6 m sec-1; 2 and 13 mph), ALFAM model estimates of cumulative NH4-N retention were 40 to 60% for liquid biosolids, and 0 to 30% for dewatered biosolids. In all scenarios, over half of cumulative modeled NH3 loss occurred during the first day after application, demonstrating that tillage more than 1 d after application will have small impact on NH3 retention. The ALFAM model outputs provided additional justification for Pacific Northwest Extension guidance for agronomic biosolids application rates. Other simple computer simulation models may prove useful in examining Extension estimates of NH3 loss from organic materials from a new perspective.
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  • Sullivan, D.M. 2007. Developing Extension guidance for management effects on ammonia loss: a computer simulation modeling approach. p. 56-61. In: Proc. Western Nutrient Management Conference (vol 7). Salt Lake City, UT.
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  • Salt Lake City, Utah, USA
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