I am going to try something with hedges. So, part of my research goes back to the osage-orange hedges on the Great Plains. According to learned people, the reason the O-O hedge is no longer used, is that barbed wire cheaper. But to look into "high efficiency" farming, that outer 20 feet or so of a field being hedge, and not "useful soil" eats into profits.
Just how does a hedge that takes up the outer 20 feet of a field, affect things? People talk about pleating O-O hedge, and perhaps some people did. I think most O-O hedge was just palisade
trees because those thorns are awful to deal with.
Assuming square fields, and that the shielding effect of trees is 7 times height, and our hedge height is 20 feet.
- a 1 acre field is about 209 feet on a side. We lose 34.7% to hedge, but our field is 82.8% sheltered from the wind.
- a 10 acre field is 660 feet on a side. We lose 11.8% to hedge, but our field is 22.6% sheltered.
- a 40 acre field is 1320 feet on a side. We lose 6% to hedge, and we are 10.9% sheltered.
- a 100 acre field is 2087 feet on a side. We lose 3.8% to hedge and we are 6.8% sheltered.
- a 160 acre field is 2640 feet on a side. We lose 3% to hedge and we are 5% sheltered.
A 160 acre field is also known as a "quarter section", which is half mile by half mile. I think for people "serious" about farming (at least in this part of the world), you need at least 1 quarter (section). I don't know what the distribution of field sizes looked like when barbed wire came on the scene. Just for argument's sake, I am going to assume 160 acres.
There are lots of farms using center pivot
irrigation, which irrigates about 78.5% of the field (you can push water further "out", but this requires a smart system so that one pushes water further out based on the position of the irrigation equipment). So let's assume stupid center pivot irrigation at 78.5%.
Barb Wire Salesman: if you cut down that hedge and plant it to productive crop, you will make so much more money, you will be rich in no time.
That hedge is only taking 3% of the field. I think 3% is well within the natural variation of yield for a crop on a 160 acre field, even today.
Yes, we are assuming the hedge is 20 foot tall, so shadows will be cast on the crop, and some of the crop will have reduced daylight hours. An affect of windbreaks can be to elevate ground level
carbon dioxide. In the past, this was a factor which
led to increased production. With climate change, it may lead to increased production. There are studies which show increased carbon dioxide can lead to changes to nutrients in the product (
hay, grain, ...). Not necessarily changes one wants.
I live in a windy place. I planted 76 corn plants (started in pots), and even though I planted in a semi-sheltered location, I think I lost most of the corn to the wind (and the growing season is just starting). Having a windbreak shields some of the field from direct wind effects. A common effect for farming, is "lodging". The crop has been knocked down to the ground by the wind. But, in a quarter section field, I can expect about 140 feet of the 2640 foot width to be protected from wind affects. We lost 3% to having the hedge there, and it shields about 6% of the crop (at a 20 foot height). In a wide open prairie (which is what the people here seem to want), to have all the crop lodged means no harvest. Harvesting 6% may give you
enough seed for next year.
What else does wind effect? It can cause pollen to drift. It can make it difficult for pollinators to do their job. In some crops, decreased winds has been shown to increase yields.
If a person is going to grow crops like special varieties of corn, looking at the 1 acre field is useful. Essentially the entire field is shielded from the wind (a slight increase in hedge height would easily make it 100% mathematically). You could grow different kinds of corn in adjoining fields.
Let's look briefly at center pivot irrigation on a 10 acre field (660 feet on an side). The center pivot reaches the edge of the field at the half way points. But in the corners, it comes short (with a stupid irrigation system). To get to the corners, is to send water at least another 20% further. On our 10 acre example, that is about 137 feet. A person can set up a substantial windbreak given 137 feet of space. Not all corners are the same, so you have different requirements for windbreak based on your prevailing winds. If we have much more than 10 acres available, and are setting up an array of 10 acre fields, we can orient them so that we get the most wind shielding.
I don't think the farmers gave up osage-orange as a hedge for economic reasons. I think barbed wire is a convenient excuse. If the only animals that affect your livelihood are domesticated horses, cows, sheep, pigs, goats and so on, there may be a barbed wire
fence in your future. If other kinds of animals (such as
deer, moose, elk, buffalo, ...) are in your area; the standard 5 foot tall barbed wire
fence (or a 5 foot board fence) is not going to help you. Some species of "deer" (which includes moose and elk) can jump more than 10 feet. I believe 14 foot is the limit.
Robotics may allow for osage-orange hedge to become more viable. If
honey locust is possible, or a replacement for O-O; robotics may allow for the thorned variety of honey locust to be used (much larger thorns than O-O).
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For the fields sizes that were around when barbed wire came on the scene, the reason to switch to barbed wire has nothing to do with increased profits for farmers. It is just salespersonship. If the only thing challenging your fence is the neighbour's cow, a 5 foot barbed wire fence may be reasonable. If you have "deer" problems, a 5 foot barbd wire fence is just a minor anoyance to them. You need something else.
As near as I can tell, the arguments for getting rid (or never establishing) windbreaks on field edges are just more "fairy dust" from salespeople.
You want the windbreaks. How wide and how tall governs what you
should try for. And there are no end of articles about pollinators and windbreaks. More
bees means more happiness. I'm not sure about more wasps.