Monday, October 31, 2022

Putnam County, Ohio


One burning question regarding population overshoot involves the degree of overshoot that may have occurred in the rural areas that many of my readers have chosen to live in.

To get a handle on that, I picked a county in the heart of the eastern corn-belt, Putnam County, Ohio. Putnam County is blessed with fertile (if somewhat clay-ey) soils and generous natural rainfall in most years. There are hundreds of other counties I could have picked but I threw a dart and this is the one it hit.

Here are a few overhead images

The entire county

A closer view from somewhere near the center of the county.

Maybe 5% of the land has been intentionally left in woodlots. Darned fine farming country.

Population history

One peak was at 1900. Growing industry in Findley and Toledo started pulling the younger people off the farm. Automation both made bigger farms possible and mandatory. That equipment had to be paid off.

In 1890, the ideal farm in Ohio might be 40 acres with 10% of it left in woods for heating and construction material. At one time, the rule-of-thumb for defining an acre was the amount of land that could be plowed by a team of oxen in a day. That means that 36 acres of land would take five weeks of good weather to plow which is way too long to put in a single crop.

Farmers worked around the constraint in several ways. One was to divide their 36 acres into four plots and use a Corn-Oats or Beans-Wheat-forage rotation. The forage was necessary to feed the draft animals and was plowed-down to provide nitrogen for the corn. Instead of having to plow 36 acres in a single go, they only had to plow 9 acres in three separate time-windows.

Another work-around was to use horses or teams of horses. Horses walk faster than oxen and larger teams can pull two plow-shares instead of a single. More animals demand that a larger portion of the farm be dedicated to growing food for the draft animals.

Population density

Using our very crude 40 acres-per-farm and six people per household, we come up with a population density =640(acres per square mile)/40 (acres per farm)*6 (people per farm) or 96 people per square mile.

Six people per household was chosen as that is a multi-generational farm, two children, two parents, two grandparents...or a modest sized family in 1900.

The current population density of Putnam County is 74 people per square mile.

One assumption that is buried in the back-of-envelop calculations is that loss of petroleum inputs in agriculture will make the work far more labor intensive and productive agriculture will require many, many times more "farmers" laboring in the fields.

Another piece of background information is that we know much more about nitrogen fixation and the role nitrogen plays in grain yield. If the "target yield" in 1930 was 40 bushels of corn per acre that same field can yield 200 bushels per acre in 2020. The cost of eliminating petroleum or natural gas derived fertilizer is that you could only grow corn one-year-in-four and expect that kind of yield.

Pencil whipping estimates

Let's cut ourselves some slack and estimate 

150 bushels-per-acre corn * 9 acres = 1350 bu = $8800 at current prices

50 bushels-per-acre soybeans * 9 acres = 450 bu = $6300

60 bushels-per-acre wheat * 9 acres = 540 bu = $4880

Gross yearly revenue of about $20k.

Gross Calories of human-quality food of about 240M, of which some will be diverted to feeding draft animals (and chickens, pigs and dairy cows). Shipping grain off-farm to feed animals somewhere else interrupts the efficient, on-farm cycling of nutrients.

Obviously this picture is painted with very broad brush-strokes and you can argue the numbers I chose. But it does plant one stake in the ground.


  1. In the next county over west of us there is a farmer just west of Marion that used to hold the record for corn yield but that was 20 years ago and he has since gone to his maker . Anyway he averaged over 400 bushels per acre in that flat black loam of Marion County . I read about the current record holder in Virginny that is looking at over 600 bushels . I don't think that will be sustainable in the very near future . Energy is losing the war here and we will soon be growing our own corn something tells me . I'll be growing an old open pollinated dent corn I got back in the 80's from a guy that developed it for optimum nutritional value for both people and livestock . I been saving seeds for many years and it looks like that is the future . It is a pain bagging them to prevent pollination from GMO's but worth it to keep it pure . The smallhold is coming back .

  2. any chance of you selling some of that seed corn, robehr?

    1. I will not have enough this year but I'll keep you in mind next year if you like. Smut got me real good this year . But the Mexicans pay well for rich organic smut . It is the best I ever had . We had rain 5 out of every 7 days this year and the huitlacoche fungus took over . I mulched the corn expecting a dry year but Mother Nature got me again . Smut big as your head on some ears . We have a large population of Breakfast Tacos as Dr Jill says so eloquently so it's not all bad .

  3. And then there is the almost total loss of the centuries of farm knowledge lost in the last 3 or 4 generations . And those of us that have even a little bit of it that we learned decades ago are old and don't have much time left. ---ken

    1. That is huge, Ken. The lost of institutional, practical agriculture knowledge is not something that can be won back except by hard experience. We will be retracing steps we walked 2,000 years earlier.

  4. Before I moved to Alaska I spent twelve years on a dairy farm in the Northern Catskills of New York. At that time in the late seventies and early eighties there was much land in the region that was farmed from the 1800’s until motor cars came along. These were mostly forty acre farms with small fields surrounded by stone walls. Many had roads too steep for cars in bad weather and often fields too steep to work with tractors or the farm too small to justify the expense of mechanization. By the seventies the poorest or steepest land was grown up to trees and the better land consolidated to a much smaller number of working farms. By the time I left there much land was being subdivided to hobby farms and hunting plots for people coming up from the cities. This along with the government dairy buyouts and the end to much of the government ag loans further hurt farming. So land that fed people and had enough rain to not need irrigation is out of production while western lands needing scarce irrigation water or land that is no longer farmable because it has become too saline because of irrigation leaves us wondering how long we can feed the world without major changes.

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  6. Getting a team of work horses and associated track has been on my mind for a couple years. The tradeoff is the amount of feed and training required in the interim when petroleum is still available. Only so many hours in the day and that is a bigger constraint than money.

  7. Energy and commercial fertilizer are huge and not acknowledged by most of the beneficiaries of those, except in passing (or protesting against both). I would posit that modern Western Civilization cannot survive in its current form without both.

  8. I forage wild edible mushrooms in the mountains throughout the year. Even in winter there are species that flush under the right weather conditions.

    My guesstimate has been the land can support 10 foragers per two square miles. And believe me, there's a lot more than that. Once they find a patch, they'll strip it clean. So, there's always a need to explore new areas.

    I trespass a lot. But I use the county tax assessor's GIS to determine if it's government owned, investor land, or somebody's backyard before I do. Then follow the animal trails.

    There's a bear every 2 square miles. That 400lbs of MM wrestler I've encountered on a trail probably thinks the same of me as I do of other foragers. Fortunately, he's been polite. Other competitors for the same resources might be coyotes, foxes, deer, raccoon, squirrel, turtle, and insects. Even bees eat mushrooms.

    At retail prices, we annually eat an estimated $3,000 in foraged wild edible mushrooms.