Tilling and planting one acre of corn (31000 seeds) with a modern tractor takes only about 18 minutes. So, a single farmer can farm many thousands of acres of corn. What used to be a major undertaking, requiring lots of manpower, now can be done with relative ease by just a few hard-working farmers (using lots of machines, chemicals and GMOs).
Once the corn starts growing it is sprayed with liberty weed-killer. This herbicide is non-selective, meaning it kills any and all plants. The corn, however, is genetically modified Liberty-Link corn that can resist the herbicide.
Ammonia fertilizer is used to increase yields. It quadruples the farm's yield and eliminates the need to rotate crops, like the Romans used to do. So, a monoculture of corn can be grown everywhere, year-after-year. However, as farmers are only now discovering, ammonia gradually destroys soil quality.
The harvested corn is used mainly for either animal feed or high-fructose corn syrup production.
Instead of letting cattle eat grass off fields, the fields are used to grow corn. This corn is then fed to the cows in a feed lot. The benefit is that since cows are not allowed to move, they fatten up more quickly. Corn is also a much richer diet than grass, so the cows gain weight even more quickly and less overall space is required. A cow is usually slaughters within 60 - 120 days of entering the feed lot.
Why 120 days? Because after 120 days on a corn diet a cow starts getting really sick. Its digestion system can't handle eating corn for so long. It develops a condition called acidosis, which will quickly kill the animal (humans can also develop acidosis, but usually only as a side effect of certain pharmaceutical drugs). Antibiotics are mixed in with the corn feed to keep the cattle alive for a bit longer, so they gain enough weight for slaughter.
Modern corn cannot be eaten by humans. It is optimized to produce maximum starch. You don't get something for nothing. So, the price of more starch is lower protein in the corn. The result: corn that tastes like chalk, has almost no nutritional value and is perfect for high-fructose corn syrup production.
One in eight people in New York have diabetes (although most don't know it) largely because of eating (and especially drinking) too much high-fructose corn syrup. Drinking one soda per day doubles one's chance of developing diabetes as opposed to someone who only occasionally drinks a soda. And the main ingredient in sugar water is ... high-fructose corn syrup.
Also, a typical McDonald's meal is basically all corn: The burger is made from corn feed cows, half the calories in french-fries come from the corn oil it is fried in, and the drink is, of course, mostly high-fructose corn syrup. We are what we eat, and what we are eating is primarily corn.
Government subsidies rewards the overproduction of cheap corn. Otherwise, it wouldn't be economically viable to grow so much corn. However, largely as a result of those subsidies, in the USA only 16% of people's income is spent on food. That's half the amount that people spent on food a generation ago. People like it when their food is cheap. More money to spend on other, more important things in life, right? The unfortunate side-effect is that low quality food makes people sick. Life expectation is actually going down in the USA. People are dying younger and it's because of what they eat.
The Bhagavad-Gita affirms all this. In it Krishna declares that wretched persons ingest only suffering when they cook for their selfish motives (BG3.13). (alternative translation credit: Garuda das)