Some blueberry farms and vineyards here in Oregon use large fans to mix the higher/warmer layers of air with cooler/lower layers, or “drain” cold air away (by blowing it straight up, it apparently doesn’t come back down). This keeps cold air from pooling in certain areas, which is what is needed to cause frost damage.
Here are some large mixers, which might be mistaken for small windmills. These are powered by propane (I think), which is what the tanks nearby hold. The heat produced is a bonus, even a degree can make all the difference: https://maps.app.goo.gl/d6UwmpPsYih5xkZD9
So while helicopters used to shake water off of crops can sound crazy, it’s literally a big mobile fan you can call in when needed to save your established perennial crop from much more expensive problems (like a disease epidemic, which now requires bacteria codes/fungicides instead of just burning some fuel. Which can make sense.
We also use helicopters to harvest Christmas trees. It’s too damn wet in the fall/winter to run most wheeled equipment up and down those horrible on red clay hills, which often have artesian springs temporarily form, resulting in clay mud that can grab and hold all land vehicles.
> Agriculture is a whole lot of “sure it’s stupid, but it works and is cheaper than the alternative”
The fan idea is actually quite okay, cold pockets exist. But let us not forget that "cheaper than the alternative" depends on the prices of everything else.
The problem capitalism constantly keeps running into is that certain externalities are not priced into that "cheaper" choice. You can defrost your fruit with helicopters if the fuel and helicopters are cheap enough, but you may be happily stacking a debt elsewhere, e.g. in the form of polution, social costs, climate crisis, draught etc.
The problem here is that these externalized costs are often not paid by the people who stack them up, which is when regulation can become increasingly benefitial.
Granted, the "crazier" measures like defrosting fruit with helicopters are often just limited stop-band measures in a bad phase that can safe a whole harvest, but if they are used to battle the stacking hidden cost they are in the danger of becoming more and more common while making the problems worse (or at least masking it).
An example: I grew up in the Alps, where skiing is a thing. Each year ski resorts have to rely more and more on artifical snow, which uses extreme amounts of energy and water. Climate change means that the snow mark moves higher and higher each winter, but what about the communities that built a living around the slope and it's tourism if it is their resort that has no snow this winter? That's when you go in with the artifical snow. Twenty years ago that may have been a few bad days in the year or just small parts of the slope, and over slow creeping times it has become more and more. The problem is it just prolongs the needed change, it doesn't solve it. Maybe they are lucky and blessed with snow next year, but what about 10 years down the line? The good ski resort villages are already aware that this is an issue and try to move more towards summer tourism, with the artifical snow just buying them time to do that transformation.
But the only reason they have to do that is because energy is expensive and artifical snow works only down to certain temperatures (to warm and it cannot be produced). These limiting factors may not exist elswhere.
There also are propane burners used to heat the orchards. Some are even dragged through the rows to provide heat. We used to get more citrus that was frost damaged, I can't remember any in the last few years but that may just be luck/where I am buying.
More details here: https://www.theweathernetwork.com/en/news/nature/outdoors/fa...