If you read one book about Iowa this year, read “The Swine Republic: Iowa’s Struggle With the Truth About Its Polluted Water and Agriculture” by Chris Jones, a hydrology expert who retires from the University of Iowa this week.

“Swine Republic,” published by Ice Cube Press in Iowa City, goes on sale May 19.

It’s a collection of 67 essays. Most are short, only a few pages long, and contain dry humor that plays off titles like “Cropaganda,” “Malice in Wonderland” and “Catch 2022.”

The book opens with a fast-moving scene-setter that traces Iowa’s geology and farm history. 

It tells how early settlers in northern Iowa “lowered the water table four feet” with field tile and ditches to create a perfect place to grow corn, which, as all farmers know, “doesn’t like wet feet.” 

You’ll read about John Deere’s first steel plow in 1837, about the first gasoline-powered tractor in 1892, and how tractors replaced horses that ate oats, which at one time was an important crop for soil health. 

You’ll learn how and why corn and soybeans became Iowa’s iconic crops and what that meant for soil conditions and clean water. 

The chief consumers of Iowa corn and soybeans are farm animals, which leads to Jones’ second essay: “Iowa’s Real Population.” It’s an eye-opener that compares the amount of waste produced by farm animals and comes up with a startling statistic. 

You probably already know there are more farm animals than people in Iowa. There are roughly 25 million hogs, 2 million cattle, 80 million chickens and 4.7 million turkeys in a state with 3.2 million humans. 

But I doubt you know what that means in terms of waste. A 250-pound hog excretes more than three times as much waste as a human. The numbers are different for cattle, chickens and turkeys, but the idea is similar. 

Jones does the math and figures out that Iowa’s hogs produce the same amount of waste as 84 million people; Iowa cattle, 34 million people; chickens, 15 million people; and turkeys, 900,000 people. 

Altogether Iowa’s farm animal waste is the equivalent of 134 million people, “which would place Iowa as the 10th most populous country in the world, right behind Russia,” Jones wrote.  

Given those numbers it’s easy to see why Iowa’s farm animal population, which has exploded in recent decades, is a big part of our clean water problem. Unlike human waste, which is treated at sewage plants, most animal manure is spread on farm fields as fertilizer for crops. 

For the last half century, the overapplication of manure and commercial fertilizers has been a growing problem, creating all sorts of environmental issues that are never adequately addressed.

In an essay titled “Cry Me a Raccoon River,” Jones notes that increased rainfall and field tiling are compounding problems by creating a vicious circle. 

Rainfall in the Raccoon River watershed has increased dramatically in the past 50 years, periodically washing away fertilizer, prompting the application of more fertilizer and manure, which is carried away even quicker by ever-newer and more efficient drainage systems. 

It’s a no-win situation for Des Moines people and others who depend on the Raccoon River for drinking water. 

The Des Moines Water Works already has the largest nitrate removal system in the country, if not the world, which says nothing about what the nitrates and other pollution are doing when they flow down the Mississippi River and end up in the Gulf of Mexico’s “dead zone” where it is impossible for any life to exist. 

At the end of the book, Jones offers three solutions. First, he says, we need meaningful regulation of the production of Iowa corn, soybeans and farm animals. Second, Iowa farms need to become more diversified, so they aren’t all growing the same crops and animals. Third, we need to “get rid of fuel ethanol,” which is the reason too much corn is grown in areas ill-suited for it.

Jones is not optimistic, and given that state officials appear to be running as fast as they can away from the problem, I suspect he is right.