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Leaving a Data Legacy:
A Minnesota Farmís Living History

Precision Farming
Written By:  Gary Wagner
December 1997
>>see the online article from Precision Farming

To the Wagner boys, who grew up on the family farm, farming was a way of life. From their father and their experiences, the Wagner men have learned some important lessons: farming is an art, and knowledge lost can never be regained.  Today, they are using precision farming techniques to practice their art and to preserve their knowledge for future farmers.

My father, Alvin, spent 40 years getting to know his land in Minnesotaís Red River Valley.  By the time he passes away at the age of 54, he knew just about all there was to know about the 1,200 acres he cultivated. He could tell you which areas of the fields were best and poorest yielding. He knew where the soil was the richest, where the low spots were in the field, and where he needed more drainage.  To him, farming was more of an art than a science.

Itís that way for my brothers and me, too. Because my dad died young, we were barely adults when we became responsible for the farm - Wayne and I were in our early twenties and Daryl was in his mid-teens. Unfortunately, although we had worked beside Dad as kids, we didnít know the productivity of the land the way he did. All his knowledge was stored in his head, so when he went, it went with him. As we took our turn running the operation, we started nearly from scratch.  We had to gather the knowledge  my father took with him all over again. It took us 10-15 years to accomplish this. Todayís young farmers, especially when they are leasing the land, donít have that much time to spare.  They need to know their fields now. They need production at maximum capacity as soon as possible.

Some of the activities our farm is participating in today can help alleviate this problem of lost knowledge. By building a historic database of the conditions and activities on our land, we can pass this knowledge on to our successor immediately.  Then whoever succeeds us when we retire, wonít have to start all over again.  Thatís just one of the benefits of todayís precision farming techniques, methods that my brothers and I have incorporated into our daily practices as we try to improve management of our third-generation family farm.

Daryl Wagner (left) Wayne and Gary Wagner (right)

The Wagners have been using computers to run their farm since the 1970s. Here (left), Daryl spot applies chemicals using a 30 foot boom mounted on the farmís all-terrain vehicle.  A prescription map displayed on the laptop computer helps to guide his application.

Wayne and Gary Wagner (right) have never been computer phobic. They own a pen-based, two laptop, and several desktop computers, which they move from truck cab to combine to all-terrain vehicle as needs arise.

A Dynamic Operation

Our farm sits at the heart of the Red River Valley of the north, an extremely fertile agricultural area encompassing the upper part of Minnesota and North Dakota. The valley is about 45-50 miles wide, and extends from the border of North and South Dakota well into Canada. The terrain is very flat.  In any given mile, the elevation may vary only three or four feet.  The area receives about 24 inches of precipitation each year, with temperature extremes ranging from -45 degrees F during midwinter to 100 degrees F at the height of the summer. During the winter months, because of our flat terrain, we often experience high winds and low visibility.  This is the environment in which my brothers and I now cultivate approximately 4,000 acres of sugar beets, soybeans, and small grains.

Roll with the changes. One of the benefits of having taken over the farm at such a young age was that we were open to new ideas.  Since the first personal computer was released in the early 1970ís, we felt this took could some day benefit our farm. By the mid-1970s, we were using a computer to keep our financial and general field records. Little did we know, adopting computer technology then would allow us to adopt precision farming techniques more quickly in the future.

Our introduction to precision farming occurred in fall 1993, a a fluke.  Pierre Roberts, a professor at the University of Minnesota-St. Paul, wanted the Northwest Experiment Station, in our home-town, to evaluate a new yield monitor. Software developer Ted Macy was overseeing the marriage of this monitor to a Global Positioning System (GPS) receiver.  To our benefit, the monitor, at that time, only worked on a John Deere 9600 combine, and the experiment station had two Massey Ferguson combines. The head of the station, Larry Smith, knew our farm had a John Deere and knew we used computers extensively. Smith referred Roberts and Macy to our farm. They called, and the rest is history.

Getting our Feet Wet

Macy brought out the yield monitor, which reflects harvest amounts in bushels per acre on its liquid crystal display. My brothers and I installed it inside the combineís cab. To georeference the data, Macy installed a differential-ready, six-channel, L1, C/A-code GPS receiver in the cab.

On the combineís roof, he mounted the GPS antenna. He installed a corrections antenna atop one of the farmís outbuildings.

Macy stuck around for about one week adjusting the software and monitoring our harvest. Each day, he programmed the equipment back at his motel room, trying to successfully merge the position and harvest data, and then came out to ride with me in the combine. By the time the harvest was done, we had generated maps for six of our 26 wheat fields. The maps revealed much greater variation in our yields then we thought possible.  They also clearly showed the benefits of on-the-go moisture sensing and indicated that we were losing money because of inadequate drainage.

At the end of the season, Macy gave us the option of returning the equipment or buying it.  As just about any farmer knows, once you have a new tool in your combine that helps you do your job better, you wonít let it go. We bought it and are still using it today.

In addition to this original configuration, we now have a pen-based computer, a rugged sized laptop, and a 486 laptop.  Our GPS unit has a magnetic-mount antenna, enabling us to transfer the receiver between vehicles.  Generally, the equipment just stays in my cab, and the computer mounts on a rack on my truck.  That way, I can do field scouting anytime I want. During the winter months, though, the equipment has to come indoors every night because it freezes so often here. I also use our Kawasaki Mule for field scouting, and I just carry the equipment on board.

Baggin and Tagging

After purchasing the yield-monitoring equipment, we began to delve into grid soil sampling and variable-rate technologies (VRT). The local experiment station showed us a three-year study revealing that variable-rate application of nitrogen in sugar beet fields had increased growersí returns by $50-70 per acre.  Partly because of this study, the number of acres being soil sampled in the valley went from a few thousand in 1995, to more than 150,000 acres today.

Sugar beets are the ideal crop for using VRT because they respond so well to nitrogen fertilzer, which affects the quality (increasing or decreasing the sugar content) of the crop.  Using VRT techniques, growers can stress the crop several weeks before harvest. This forces the plant into premature dormancy, thus increasing sugar content.  Because growers receive a premium incentive to increase sugar content, this can be a very worthwhile endeavor.

But, before they can write a prescription for the VRT application, farmers must grid sample soils.  To do this, growers in the valley pull nitrogen samples from 0-24 and 24-48 inch depths. Phosphate, potassium, and other nutrients are generally analyzed at 0-6 inches. Sampling a typical 160-acre sugar beet field on a grid costs about $2,100.  Factor in the cost of VRT application at about $6-9 per acre, and this process can become cost prohibitive despite the potential gains resulting from increased sugar content.

Proceeding with caution. We were a little slower to dive into this costly undertaking than many of our neighbors.  Before we started to conduct VRT in our fields, we wanted at least three years of yield data as a baseline.  That way, when we changed management practices, we could determine if the investment was really increasing our bottom line. Because we are still learning about this technology and its benefits, the baseline will also help us to select fields that have a better potential for responding to VRT. Some of our neighbors, who were early adopters, have become discouraged with VRT, feeling it has not lived up to its promise. Many times, farmers conducted VRT in a problem field and expected a one-time fertilizer application to correct all the sins committed to the land over many years. Looking back, I think our decision to go slowly was a wise one.

When we did finally get involved with this aspect of precision farming, we soil sampled nearly 3,000 acres to prepare for VRT applications.  Because our soils are so rich in organic materials, most of the time we test only for nitrogen and potassium. After extracting soil from the appropriate depths to determine element, inorganic matter, and soluble salt levels, we obtain a GPS reading using our six channel GPS receiver. We place the sample in a Ziploc baggy and label it with the source coordinates. Then, we send the samples to a soil analysis lab in Grand Forks, North Dakota.  It returns the analysis to the farm in spreadsheet format, which I flow into another spreadsheet program. Then, we bring the information into the farmís GIS database and - based on the University of Minnesoat-St. Paulís recommendations - we develop a prescription map for fertilizer applications.

Variable Rate Equipment

To eliminate the cost of a custom variable-rate application service, the Wagner brothers grow their own.  Their air drill has two compartments in its supply tank. The brothers use this equipment to apply nutrients as well as to seed, making it a dual-use investment.

Do It Yourself

Although most of our neighbors rely on a service for their VRT application, we decided to conduct our own. We bought an air drill and installed controllers to facilitate the variable rate. We originally purchased the air drill to plant our small grain crop. By also using it to fertilize, we are making dual use of the investment.

The air drillís supply tank has two compartments.  We use one for phosphate (18-46-00) and the other for potassium (00-00-60).  The drill bands the nitrogen, phosphate, and potassium in narrow strips (1-inch wide, 10 inches on center, and 3-4 inches deep) in accordance with the prescription map.  Using this technique, we have our zones.  The smallest zone we deal with for VRT prescriptions is around two acres, the largest around 35 acres.

Double Checking Data

To further confirm our management decisions, my brothers and I wanted to review a longer history of our fields.  I went to the local farm services office and purchased compliance slides of our farm dating back to 1980. I took these slides to a service bureau that digitized them and put them on a CD-ROM. I am now in the process of false-coloring all those pictures and georeferenceing them in the farmís GIS.  When Iím through, they will be added to the extensive data library we are building of the farmís past production.

Since 1993, we have slowly been discovering how valuable such crop production information is and how difficult it is to interpret. For example, the very first yield map we produced in 1993 was of a wheat field.  We found a low yielding area within that field. After a lot of head scratching, fertilizer analysis, and wild guesses, we finally determined that the low yield was the result of soil compaction.

For four years, we were sure that this was the case. Then, in mid-June 1997, we obtained a false-colored aerial picture that showed the same pattern we had seen in 1993.  We began to investigate the problem further, conducting ground truthing (or physically walking and ďeyeballingĒ the problem area). This revealed that the wheat plants had lost all of their tillers.  We revised our interpretation of the problem, determining that this area was prone to drought stress.  We gathered other information, such as weather data, soil survey, topography, soil texture, and finally the yield map for the 1997 crop year, all of which confirmed our new conclusion -  drought stress, something we canít do anything about.  We are certain that this determination is more accurate than our original decision. And it took us only five years to figure it out. (Boy, are we in for a long career!)

Color Aerial Images

Figure 1. This color aerial image was taken in June 1997.

Figure 2. Wagner then false-colored the same photograph to augment individual pixels and reveal distinct patterns.  By enhancing the imagery he was already gathering, he could see ever-more subtle variations in his fields.

Separating Wheat from Chaff

One of the biggest challenges growers face when implementing these new information-based techniques is knowing what data to collect.  Right now, farming are still trying to figure out what information is most important. We seem to be collecting everything, with plans to sort it out later. Iím certainly no exception to this.

Currently, I have maps covering five years of small-grain yields (including soybeans, sunflowers, wheat, and barley), two years of sugar beet yields, three years of satellite images, 17 years of aerial photographs, topography maps for nearly half of our acres (soon to be completed), soil survey information, soil texture analysis, 27 years of soil fertility maps, all surface-drainage patterns, images of my wife, and my kids, and my dog..oh sorry - sometimes we get carried away. We also have rainfall patterns for two years gathered from 38 rain gauges scattered throughout the farm, plant populations for one year of our sugar beet crop, and extensive information about plant residue in two fields.  Before the year is through, I hope to have mapped my entire acreage.

Sound like overkill? Well, maybe, but Iím building a data legacy. If I had to run control of my farm over to a young farmer today, that grower would have a well-documented multiple year history of the farmís activities and production. Also, by gathering as much as I can, then analyzing the correlationís and associations between the many factors, I hope to learn just what factors are important and what data are beneficial.  By interacting with the graphics, maybe I can learn from them.

But, no matter how much high-tech equipment I deploy, no matter how many maps or data layers I create, the knowledge stored in my head can never quite be replaced. If all the minor things in a farmerís mind were flowed into a GIS database, the layers would be innumerable.  Only I know where the chain fell off the fertilizer spreader, or where I applied the incorrect herbicide rate in a small area, or any number of other little mistakes.

As a prime example of this, I was recently reviewing a 1996 sugar beet yield map, when I noticed that something didnít look quite right.  I kept going over it in my mind.  When I was viewing my compliance slides, I recalled that in 1987 we had a small strip of summer fallow. Then, in 1988, we had planted sugar beets in this fallowed area. According to our records, this 30-acre strip out yielded the rest of the field by nearly 5 tons per acre. In succeeding years, we never treated this area any different. Maybe (this is still a guess) the decisions we made many years ago are still affecting yields today. Only time will tell.

The everyday experiences of the person who works the land must be taken into account and most of the analysis must be done in the farmerís mind.  The involved owner-operator still knows better than any artificial intelligence, whatís going on within his field.

As said earlier, farming is an art.

Aerial Maps

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As he correlated different types of data - by laying maps of such factors as soil survey and topography over aerial images in his GIS - Gary Wagner began to see that spatial variations followed naturally defined polygons as revealed in the above three images. He also determined that his fields should be broken down into much smaller zones for site-specific management than he had ever before believed.

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