Electronics In Agriculture

Planting and harvesting on large farms is now assisted by highly computerized machines with GPS and automatic steering.


In my post Jobs: Farmer I wrote about my experience as a teenager working on the farm owned (actually rented from the Duke of Badminton) by the father of one of my school friends. Electronics were nowhere to be found in those days. I recently watched some YouTube videos that show just how hi-tech farming has become now that Moore’s Law has made accessible electronics that would have seemed magic a couple of decades ago. Arthur C. Clarke is famous for saying “Any sufficiently advanced technology is indistinguishable from magic.” Before I bring you the magic, let me tell you how it worked when I was doing it.

Before electronics

I worked on the farm during harvest. I’m not going to explain how a combine harvester works. For the purpose of this post, all you need to know is that the crop goes in at the front end where that big spiky cylinder (called the “reel”) revolves. Magic happens inside. Waste material is ejected out of the back. The crop itself accumulates in a storage area on the combine known as the tank. So what happens when the tank is full? Well, what you don’t do is drive the combine back to the farm and empty it into the storage bins! Someone (that would sometimes be me) drives up alongside the combine with a tractor and trailer, and the combine empties the tank into the trailer through that long pipe sticking out the side known as an auger. The normal way to do this is on-the-go, the combine keeps moving and the driver of the tractor (aka me) has to keep pace alongside so that all the grain goes into the trailer and not onto the ground. The easiest thing to do is fill the front of the trailer, near the tractor. But you actually need to start at the back, otherwise you will build up so much grain at the front of the trailer that you can’t even see the back, so you can’t fill up the rear of the trailer to full capacity without risking getting ahead of the combine and grain going onto the ground. The biggest challenge was at night since there wasn’t really good illumination into the trailer to see exactly what was going on, and even though the combine could turn off the one headlight on that side, it was still a bit like looking into someone’s high beams. Here’s a picture to make it clearer:

This picture is a stock photo apparently taken in Poland this year (2020). I would say that the vintage of the combine and the tractor are approximately the same as when I was a teenager! Apart from having all the electronics, modern combines are much larger (wider), and modern tractors are bigger and more powerful.

Cole the Cornstar

YouTube somehow decided I should watch one of these videos. I find them fascinating for a couple of reasons. Firstly, my experience is all with working on a farm that grew wheat (mostly), some barley, and about one field of oats mainly to feed the horses on the farm without having to buy any feed. The farm in the videos grows soybeans and corn. The other reason is the massive amount of electronics. I’d read how “farmers use GPS these days” but I’d never seen it. Actually, the third reason is the scale of farms in the Midwest. The farm I worked on was 450 acres, divided into maybe 20 fields, of which the largest was 40 acres. That field was called…you’ll never guess…”forty acres.” The farm in the videos has fields about the size of the entire farm I worked on.

All the vehicles have autosteer so they steer themselves. There are three ways this is done. On very old tractors, you add a device that actually turns the wheel. On very modern tractors, they simply come with autosteer. In the middle, you can just access the steering hydraulics and steer the wheels without needing to turn the steering wheel.

The electronics also “know” the shape of all the fields. I have no idea how these get programmed in. It might be done by using existing electronic maps, or maybe by driving around the edge of the fields and recording it. This is especially important in oddly shaped fields since the autosteer might actually have to do more than keep going on the correct straight line.

I’m going to point you to a couple of videos, one planting, and one harvesting.


The planter is huge, and plants 24 rows of beans or corn at once. They are spaced at, I think, 20″ so this is 40 feet wide. It monitors the planter and can count the number of misfires where either no seed was planted (“skip”) or two seeds were planted (“double”). Obviously, if no seed is planted, it is wasting that little bit of ground since no crop will grow there. Two seeds are bad for two reasons: firstly, it wastes a seed and seed is expensive, but also the crop won’t do well since it will only get enough fertilizer for one plant.

The most magic is that the electronics knows where it has already planted. When it comes to the headland of the field at the end, where the tractor has to turn round to come back, it automatically stops planting just where it runs into the already planted area. Most amazing of all is when it is in a strangely shaped field and so comes at an already planted area on the diagonal. As each successive planter of the 24 reaches the already planted area, it turns off (or on in the other direction). It never plants a single seed on an area that has already been planted, even in this complex case. No field is likely to be precisely a multiple of 24 rows of seed wide, so that on the last row at the edge of the field, it will only turn on the planters that are over the unplanted area, and turn off the planters over the already planted during the last-but-one pass.

The accuracy is 1″. So the gap between two adjacent passes is within 1″ of the 20″ that the 24 rows planted in each pass are spaced at. I know it’s not 16nm, but under the circumstances, that is pretty amazing.

You can skip to 3:30 in the video if you want to get to where younger son Cooper (who, by the way, is aged 17) explains the GPS systems and gives a demonstration of all the autosteer and the planter shutoffs that I just described.


The Arthur C. Clarke magic in the harvesting is not just that the combine steers itself. The grain cart can drive itself. It also communicates with the combine and so the job I used to do as a teenager, driving at the same rate as the combine to empty it on-the-go is also automatic. It keeps a constant distance away and goes at the same rate.

Just start this video at the beginning.

By the way, when I said that the combine “steers itself” I was careful not to say it drives itself. The one thing that is a bit of a black art, and is done manually, is to determine the speed the combine goes at. The engine on a combine always runs at full revs to drive the threshing and other stuff inside. The speed the combine moves forwards is controlled manually. If you go too fast, crop enters the combine too fast to be properly processed and crop will go out the back of the combine and reduce yield. If you go too slowly…well, you are just wasting time, and time is money. Without a camera (with AI I’m sure this will come) the driver has to look at what’s coming up. If the crop is thin, the combine can speed up. If it suddenly thickens, it needs to slow down a moment in advance. If the crop is somewhat flattened, it might have to inch forward, lowering and raising the table to get as much of the crop into the harvest as possible.

How a planter works

There’s no electronics specifically involved in this, but this video shows you how a modern planter works. These used to be called “seed drills.” Do you know who invented the seed drill? Jethro Tull. Back when I was that teenager on the farm, Jethro Tull was more famous for being a rock group fronted by Ian Anderson whose rock instrument of choice was…you’ll never guess if you don’t already know…the flute. You can skip to 4 minutes where the explanation of how a planter works begins.

Here’s Wikipedia’s description of the seed drill in the Jethro Tull era:

The invention of the seed drill dramatically improved germination. The seed drill employed a series of runners spaced at the same distance as the plowed furrows. These runners, or drills, opened the furrow to a uniform depth before the seed was dropped. Behind the drills were a series of presses, metal discs which cut down the sides of the trench into which the seeds had been planted, covering them over.

If you watched the video, you’ll see it’s not that much different today, other than the number of rows that can be handled at the same time.

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