Sunday, July 14, 2019

Carrying capacity

Virtually no petroleum was used in agriculture in 1870 and even into the 1930s tractors were far from ubiquitous on the farm.
Often times it is possible to look back into history and find information that can address speculative questions.

For example, what are the carrying capacities of the communities Kates Store and Pray Church in a post-oil economy?

Looking at Census data it becomes clear that the population density in south-central Michigan's rural, agricultural areas flat-lined starting in 1870 at about forty-eight people per square mile. That population density remained essentially unchanged until the start of World War II some seventy year later.

What does forty-eight people per square mile look like?

A square mile holds 640 acres.

If the population is in maintenance mode then we are talking two children per family in round numbers.

Forty-eight people divided by four per family means that twelve families will populate the square mile. It also means that the average farm size will be a bit more than fifty acres.

That works out well because a single family that relies on horse power can farm about forty acres. Fifty acres is forty acres with a nice woodlot or permanent pasture.

Or if we are talking three-generation households we are talking six-per-household and eight families per square mile. That noodles out to eighty acres per household so there need be an emphasis on low-labor/acre crops or a system of agriculture that levels the labor demands across the year.

It should be obvious that these numbers only apply to south-central Michigan's climate and soil but the same analysis could be done for any group of counties in the United States. Wikipedia's standard format for reports on "Counties" includes census data.


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  2. 80 was considered barely subsistence in my family and 160 was much more desirable as single family farms. This was in Kansas, Missouri, Tennessee, Oklahoma, and Illinois. A good chunk of the farm was hay field and pasture. All my relatives had four to seven children.

  3. I have kinfolk in North Dakota. The homestead act let them acquire 80 acres. You had to dig a well, plant a grove, work the land and live on it for 7 years. When my great grandfather homesteaded in that area, he filed in his name and he filed in his fiance's name picking up 160 acres. When my grandfather was young there were two to four families per square mile. I surveyed the ruins of farmsteads as a young man. On the other hand, Pasture and slew cut things to a manageable level but I think they handled more than 40. My mother recounts taking sandwiches to the men in the field as a girl. So they hired. In the time of my uncle scale took the size of a small farm to 2 to 3 square miles. My cousin farms six.

  4. I agree that 40 and even 70 acres was small for a family farm. As has been pointed out, don't forget that most farming families had more than 2 kids before mechanization.

    Where I am, and likely elsewhere as well, 10 acres of woodlot isn't enough to support a house, especially if they are cooking on wood as they almost all were before the 30's.
    I heat with wood but don't cook with it and wouldn't want to live on only 10 acres of woodlot.


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