Precision Agriculture – High Technology Invades The Farm
Here at the Hub, we try to keep our finger on the pulse of technology and how it affects our lives. Farming is no exception, and it's about to get an upgrade. With scrolling ads for the latest touchscreen control system, wireless connectivity solutions, and Dell notebooks, PresionAg’s website looks more like a site for tech junkies than for farmers. The high technology decorating the website is symbolic of the infiltration of high technologies onto farms across the world. Tractors operated by touchscreens are becoming increasingly common. Words such as ‘remote sensing,’ ‘near-infrared,’ and ‘algorithm’ that evoke images of a space shuttle cockpit are steadily working their way into the vernacular of everyday farmers. Welcome to the future of farming. It's called precision agriculture.
The mechanization of farming is considered one of the top ten engineering accomplishments of the 20th century. Before the tractor it took 35 to 40 hours to plant and harvest 100 bushels of corn. Today the same amount of corn takes 2 hours and 45 minutes. The effects of this staggering increase in efficiency were felt across society at large as would-be farmers, no longer needed, moved into the cities in droves (in 1900 41 percent of the U.S. workforce were employed in agriculture; in 2000, just 1.9 percent). Now farming is poised to undergo another revolution, delivered through another of the 20th century’s technological breakthroughs: computers.
Crop fields can be huge. In places like the American Midwest and Canada fields can stretch for miles. Inefficiencies in farming operations over distances like these can raise costs exponentially. Imagine the amount of seed wasted by steering a tractor just six inches off track. Double-seeding that six inch strip is not only wasteful in terms of seeds lost, but also due to lost production of a crop now growing under suboptimal conditions. Now take that seed error and multiply it by a factor of water + fertilizer + herbicides + pesticides.
GPS to the rescue. Whereas before a farmer had to reckon with guideposts, they now have tractors that communicate with satellites. The typical guidance system you’re likely to find on a tractor has a precision of under a meter, but more advanced systems can reach sub-inch precision. And the best part is that the tractor drives itself! The GPS is hooked up to a control system that drives the tractor so the farmer can sit back, crank up the music, and enjoy the ride (watch the tractor drive itself in the video below). Considering the constant mental effort it requires to keep straight with the guideposts, the relief afforded by a hands-off ride is a significant benefit. Farmers who have switched over to GPS often cite increased productivity from less stressed drivers.
Aside from the technology, a major advancement of precision ag comes from a change in the way farmers think about their fields. In the past, a field was viewed as a uniform unit: if it’s time to water, the entire field gets watered. But the reality is that not every part of the field has the same need for water or fertilizer or pesticides. The smartness of precision ag comes in the form of what are called “variable rate technologies” that control delivery of water and chemicals according to what that subregion of the field needs.
In the past farmers could tell you what areas of the field needed more or less water from direct observation. But a farm back then was typically a few hundred acres. As the fields of today approach the massive expanses of tens of thousands of acres, comprehensive hands-on assessments are becoming impossible. At the same time, effectively managing a farm of this size requires an information gathering system that is quick and comprehensive. Remote-sensing is just this system.
Multi-spectral images taken from satellites and aircraft can provide farmers with a wide range of information about their fields. Images of red light reveal relative levels of silt, sand, calcium, and clay in the soil (soil texture is an important factor in determining the right level of water and chemical application). Readings in infrared tell you which areas receive more water and how water moves in the field. Infrared images can also be used to assess weed coverage. Images in the thermal infrared range is used to assess plant health. This is due to the fact that unhealthy plants are unable to cool off through “transpiration”—the release of water through somata on their leaves—and overheat as a result. Not surprisingly, green light which reflects off the plant’s chlorophyll is used to assess plant growth. The multi-spectral data is plugged into a computer model to generate a prescription map for the field. And it’s a pretty smart system: whether you’re scanning corn or cotton or peanut fields, the computer models used to interpret the data can be modified to take into account the physical properties of the plant. The three false-color images shown here were taken by sensors aboard NASA’s Daedalus aircraft. The top image shows crop density (dark blues and greens indicate vegetation, red indicates bare soil) the middle image maps water deficit (dark blues and greens indicate wet soil, red indicates dry) and the bottom image measures stress (red and yellow indicate high stress).
The remote-sensing data reveals to the farmer what he already knew: variability is part of the fields. So how does he use this information? The multi-spectral data is entered into a computer that then calculates the amount of water or chemicals needed, then automated sprayers vary their application accordingly as the tractor moves across the field. Known as variable rate technology (VRT), this automation again takes the hard decisions out of the farmer’s hands and gives them to computers.
Remote-sensing data is expensive, and farmers often get together and share the cost by purchasing surveys that span multiple farms. One limitation of remote sensing is time resolution. Ideally fields would be scanned on a daily basis, but many farmers simply cannot afford to hire airplanes that frequently. And satellite coverage is broad, rarely scanning the same field twice within a 24 hour period. But one needn’t always take to the air to benefit from VRTs. Several companies offer sensing systems that can be attached to tractor booms and “read” the field on the go. Like the sensors on Daedalus, these sensors take multi-spectral readings to determine plant growth and health, and this data is then used to modify output from applicators on the boom. The proximity to the plants offers the advantage of active light sensing. Because these sensors provide their own light they’re not affected by light interferences such as clouds or shadows. And they can be used at night.
The main motivation behind precision ag is, of course, to increase profit margins. A farmer who adopts the technology saves about $2 to $8 per acre. If he springs for the high-end, more sophisticated equipment, he can save up to $15 per acre. Concerns by today’s farmers hesitant to adopt the VRT approach (“We never needed that junk!” went one blog comment I saw) that the expensive equipment will drive up food prices are unfounded. The 60 percent of Alabama farmers who have adopted precision ag technologies saved an estimated $10 million in 2009. The land profits as well. Applying chemicals only to sites and in amounts needed cuts down on pollution due to runoff. But if a farmer still doesn't buy into the precision ag and finds himself soon unable to match large-scale profits, there's always the local or organic markets he can turn to.
With remote-sensing imagery, computer modeling software, and high tech tractors, this is definitely not your grandfather’s farm. While strawberry-picking robots are very cool, we’re probably a long way from seeing them roll past the cows out to pasture. Farmers are a meat-and-potatoes type of folk who need a meat-and-potato kind of technology. Precision ag is still young, and as the variable rate technologies become more capable and user-friendly they’ll reach more farms all across the world. Of course, mass food production has its downside, such as the risks of monocultures and food chain corruption. Part of me worries that the precision ag technologies will hasten the pace at which farms are growing. If we reach a point where the average farm of tomorrow looks like the industrial farm monstrosities of today, we have to ask if the pros really do outweigh the cons. But for now, as long as mass food production is going to continue, it's good to see that they're doing it in more efficiently and using less resources. A hundred years ago farming technology changed the world. I’m hopeful that a hundred years from now we might be saying the same thing.
[image credit: NASA via Wikicommons, Precisionag.com]
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