performed similar measurements
on a 20m 20m corn field surrounded by 120 m 122 m of
barren land beyond which more corn was planted. Their
experiments were limited to mean velocities lower than
1ms1 to avoid contamination of the measurements by the
surrounding corn. Vertical profiles of downwind pollen
concentrations and fluxes were obtained at 3 and 10m from
the source, using rotating-arm spore traps mounted on poles,
4 mhigh. Pollen concentrations decreased by about a factor of
3, between 3 and 10m downwind of the source with a peak
concentration located below 2m.