Question

PLEASE SHOW CALCULATIONS

Wheat pollen has a reported mean diameter of84 μm. I found a report on wheat pollen stating that whea tpollen could remain viable for as long as 14days. The USDA guidelines require a separation of 100 ft between genetically engineered wheat and conventional crops. That is, a recommended separation of at least 100feet (30.5m) to prevent GMO wheat from contaminating neighboring wheat crops. See if you can validate the rationale of this guideline.

a) Calculate the settling velocity of wheat pollen. I found a reference that reported grass pollen to have a mass density ofabout1,100kg m-3.

b) How long would it take for a grain of pollen to fall from a tassel at the top of the wheat stalk?

c) A typically breezy day has winds with a velocities that can reach20 mph(8.9m/s). Consider a rolling field of wheat with the high point of the field 30 m above the valley below. How far could a pollen grain drift released from the top of this field drift under this condition? (Assume a level and extensive valley with other farms below the wheat field.)

3d) A thermal whirlwind (e.g. dust devil)could easily lift pollen up 200 m. Fortunately, whirlwinds don’t maintain integrity in strong winds, but you still might have one in a 10 mph wind(4.5 m/s). Estimate the distance wheatpollen could drift under these conditions.e) Based on your calculations, comment on the guidelines recommended by the USDA.

Answer 1