The present controversy over genetically modified (GM) crops has led to increased interest in evaluating and controlling pollen dispersion. In response to this problem we have developed a Lagrangian model of pollen dispersion. An advantage of the Lagrangian technique is that it allows each element of the material being dispersed to be "tagged" according to its source, release time, or other properties. This capability allows pollen viability to be estimated as a function of such factors as travel time, temperature, and relative humidity. A further advantage is that the Lagrangian model can be used in arbitrary flow fields.

The model is tested by comparison to field measurements of pollen deposition. It is found to compare favorably both to observations and to results from a standard gaussian plume model. The advantage of the Lagrangian model for arbitrary flow fields is demonstrated by coupling the model with a state-of-the-art model for flow around a shelter belt. Results suggest that shelter belts may be useful for controlling pollen movement between agricultural fields.