Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/1998
Publication Date: N/A
Technical Abstract: Ammonia volatilization following application of fertilizers and effluents to crops constitutes a loss of N from the system and a potential environmental hazard. A model of gas transport in plant canopies based on Lagrangian dispersion was used to infer sources and sinks of ammonia in the canopy of a dense corn crop (LAI-5) subject to frequent irrigation with dairy effluent. Source strengths were calculated for four canopy layers from statistics of the canopy turbulence and ammonia concentrations measured at eight heights. Small ammonia losses were inferred for the soil, constituting 2 to 12 % of the total loss. Large losses occurred from the foliage in the top half of the canopy, particularly just after effluent application when they averaged 2.6 kg N ha-1 h-1. Even days after an irrigation, foliage losses were too high to be explained by diffusion through stomata and it was surmised that they were from residues remaining on leaf surfaces. It was estimated that monthly emissions exceeded 50 kg N ha-1.