Historical Iowa Farms and Average Farm Size
Keith Greiner
September 14, 2020
This page presents the historical number of Iowa farms from 1930 through 2012. Over the 82 year period there was a decline from 214,928 farms in 1930 to 88,637 in 2012. That is a decline of 126,291 and -58.8%.
During the same period, the average farm size increased from 167.4 acres to 345.5 acres. That is an increase of 106%.
This is a case where the average doesn't show the whole story. The average shows the sum of all values divided by the number of values included. It is a standard measurement of comparison. Unfortunately, it does not present an accurate distribution because the distribution of farm sizes is neither flat nor is it normally distributed. And, unfortunately, the Census of Agriculture does not use a constant space between its categories. The Census of Agriculture category range sizes are from 9 for the first category to 500 for the next to last, and an unknown for the upper category. As such, it is impossible for the user to get a true interpretation of the distribution of farms. The best that can be done is to combine ranges in the hope of finding some that make the ranges comparable. Two examples are the range from 1 through 259 vs. the category of 260 through 499. A fifty-fifty split would be a range of 1 through 250 and a range of 251 through 499. But that's not what the Census of Agriculture does. Still an imperfect comparison is possible (if we understand where it is imperfect), and is shown below. There we see that 82.8% of the farms are in the category of 1 through 259 acres, and 17.2% of the farms are within the range of 260 through 499.
By regrouping the categories, again, and including all farms, we see that 77.6% are from 1 through 499 acres, while 22.6% are from 500 or more acres.
The distribution of farms in terms of total acreage, is more evenly divided for the categories shown below. Slightly over half of the acres are in farms of size 1 to 499 acres, when we consider just the two categories of 1 to 499 vs. 260 to 499.
When the farms are divided into groups of 1 through 499 vs. 500+ we see that only 28.5% are in the smaller farms and 71.5% are in the larger farms of 500+.
Additional information may be found at this link.
Supplementary Materials for Students Enrolled in Applied Statistics, ECON 135.