An interesting article from Car & Driver magazine, June, 1980.
The conclusion?
"The test is over. It's obvious our subjects are as high as they're going to get. It is also obvious—and a little disappointing—that their driving abilities as determined by our two tests have not been particularly impaired, have not shown dramatic deterioration."
Visit the link for more details, including comments by an assistant research scientist specializing in drugs and their effects on driving at the Highway Safety Research Institute in Ann Arbor. (Hint -- the Car & Driver results are consistent with other tests.)
Gun nuts are paranoid as hell, that's why.
Are you paranoid if people are trying to do exactly what you think they are?
Every corn growing farmer in the US rotates with soybeans.
Untrue. There are fields near my house that have been in corn continuously for at least 5 years. When the price of corn is high, it's worth buying tons of fertilizer. It probably has all of the bad effects that you write about, but it happens.
It is impossible to enjoy idling thoroughly unless one has plenty of work to do. -- Jerome Klapka Jerome