I was in Iowa last week shooting for the PBS NewsHour Weekend “Future of Food” series. There are some good things going on — and you’ll see them in the segment, which will run later this summer or fall — but I left feeling depressed as hell. It’s bad enough that Iowa plays an outsized role in determining presidential candidates; its population, after all, is less than 1 percent of the country’s. But its impact on the food system is even greater, and may be even more difficult to change.

Iowa has its beauty: It’s not flat, as many seem to believe, and although the scenery is not especially dramatic, this time of year it’s lush, with free-flowing waterways everywhere. Iowa farmers generally do not irrigate, which distinguishes the state from California, of course, as does the astonishing dominance of the almost exclusively two-crop economy based on corn and soybeans.

Yet Iowa is unrecognizable from centuries ago, when Europeans took the land for themselves. What were prairie and wetlands are now neatly partitioned grids of intensely cultivated land: the model for the farm as factory. Through a system of underground “tiles” (pipes, really) in the northern half of the state, most of the water has been drained from swamps, prairie potholes, and lakes into creeks and rivers, which in turn have been engineered to maximize flow.

Thus, much of the landscape has been reshaped to make large-scale mechanical farming as productive as possible. Twenty-three million acres are planted in corn and/or soybeans; that’s 63 percent of all the land in the state, and more than the land area of each of 20 states. Nor is Iowa alone. An area the size of Montana is planted in corn every year in the United States; less than 1 percent of that is sweet corn eaten by humans.

Farmers talk of crops and equipment and prices, but not of food.

(Well, except for when they claim to be “feeding the world,” which simply isn’t true.) The ground is barely used for growing food: The grain elevator — the point of contact between the farmer and the industrial commodity system — buys only corn and soybeans. It’s near impossible for all but the most creative farmers to sell anything else.

Fifty percent of the corn in Iowa is used to produce ethanol.

Most of the rest goes to feed animals in confinement, almost all of which are behind closed doors in buildings designed for secrecy. There are 20 million hogs at any given moment in the state, and in four days of crisscrossing a patch northwest of Des Moines, I did not see one. I did see cattle, mostly crowded into muddy feedlots or, to be fair, occasionally grazing.

The farmers I spoke to don’t seem to know or care where their crop goes: Ethanol? Chicken feed? (Fifty-nine million mostly invisible chickens produce 16 billion eggs annually, statewide.) Cheetos? It’s all the same.

A nearly word-for-word conversation I had with a farmer who grows on 3,000 acres:

Q: Why do you choose a certain variety of corn or soybean?

A: Yield.

Q: Does it matter whether you’re growing for ethanol, or animal feed, or food oil, or whatever?

A: No.

Q: Do you know what happens to the grain after you sell it?

A: I have no idea. I bring my soybeans to the elevator and get a check. It gets trucked away and mixed with other grain.

That check represents less than 10 percent of the ultimate value of the grain.

I should point out — lest I be accused of ignoring the issue — that almost all industrially grown corn and soybeans start with genetically engineered seed. But that is so little a part of the problem that it’s almost not worth mentioning. Even if the seeds were traditional heirloom varieties, wonderful from every possible angle (and impossible in this system), things would suck about 1 percent less, because the problems with genetic engineering pale next to those of the general state of industrial agriculture. Glyphosate (the main ingredient in Roundup, the herbicide that is paired with crops genetically engineered to resist it but kill every other plant it touches) is fearsome stuff. But when it doesn’t work, people stop using it, and switch to another — often more toxic — chemical.