Corn pollen has a reported diameter that ranges from 22-70 micrometers... 1) Cor
ID: 3280048 • Letter: C
Question
Corn pollen has a reported diameter that ranges from 22-70 micrometers...
1) Corn pollen has a reported diameter that ranges from 22-70 m, I found a report on corn pollination stating that under ideal conditions a grain of corn pollen could remain viable for as long as 8 days. Genetic modified organisms GMO) remain controversial, and many organic farmers desire to keep their crops pure and free from genetic contamination of GMO, and that could potentially happen from windblown pollen. Thomison (2004) recommended these guidelines to protect California organic corn production from GMO contamination: For corn fields over 20 acres (8 ha), if the actual isolation distance (a required 660 feet, or 200 m) is less than 165 feet (50 m), the protocol can be modified by the postpollination removal of 16 border rows, or 40 feet (12m) of corn. For corn fields over 20 acres (8 ha), if the actual isolation distance is between 165 and 660 feet (50 and 200 m), the protocol can be modified by the postpollination removal of 8 border rows. For corn fields over 20 acres (8 ha) with an isolation distance greater that 660 feet (200 m), border rows are not necessary but are advisable. That is, a recommended separation of at least 660 feet (200 m) to prevent GMO corn from contaminating neighboring corn crops. Assess the rationale of this guideline, and whether it seems reasonable. a) 50 m seems a reasonable value for corn pollen diameter, and I found a paper that reported pollen to have a mass density of 1.44 g cm3. Corn typically grows to 8 feet tall. How long would it take for a grain of pollen to fall from a tassel at the top of the corn stalk?Explanation / Answer
(a) pollen grain falls from 8 feet height under gravity.
As g = 32 feet/s2
h = 1/2gt2
t = (2h/g)0.5 = 0.707 seconds.
This is the required time and condition is that there is mo air resistance.
(b) as pollen moves along the wind with a horizontal speed of 50 mph also falls from 8 feet height under gravity.
So as in part (a), it reaches ground in 0.707 seconds.
Now, horizontal distance covered by pollen in this times with speed 50 mph is
D = 0.707 x 50 x 5280/3600 feet = 51.85 feet
Hence, pollen drifts 51.85 feet in this wind.
(c) now pollen drops from 200 meter and moves with wind of a speed 10 mph.
Times taken to reach the ground under gravity is
t = (2H/g)0.5 = (2 x 200/9.81)0.5 = 6.3855 seconds
Now, in this time, pollen covers horizontal distance with speed 10 mph :
D = 6.3855 x 10 x 5280/3600 feet = 93.65 feet
Hence, pollen grains drifts 93.65 feet in this case.
(e) as pollen drifts for more than 40 feet, first condition may be modified