Using variable rates on the farm

Major changes in farming practices always take time, and precision agriculture is no exception.

Zero till first caught producers’ attention in the late 1970s, but it took more than 20 years to become mainstream.

Despite the obvious benefits of satellite guidance and autosteer, it took a decade for that technology to become mainstream.

Farmers began dabbling with variable rate and precision zone management in the mid-1990s, and two-thirds of all newer seeding equipment on prairie farms are variable rate compatible. However, fewer than one-quarter of prairie farmers have implemented precision zone management.

Three main factors prevent more producers from adapting zone management, AgriTrend agronomist Warren Bills said in a recent webinar:

  • The natural resistance to try new things, which is compounded by the fact that farmers are coming out of a period of good yields and good prices. The memory of those recent good times makes it difficult to implement major changes.
  • Sixty-five percent of farmers have variable rate compatible seeding rigs, but they need training in how to make it work for them. Bills said stepping straight into a zone management regime is a daunting move for farmers if they don’t have the knowledge. Part of the problem is that farmers are rightfully afraid to turn control of their fertilizer rates over to a computer.
  • There used to be a perceived lack of conclusive evidence proving that zone management pays off, but Bills said a growing amount of data now shows it can have a net benefit of $35 per acre, which is the difference between profit and loss some years.

“We’ve documented an average benefit of $35 per acre. The data is compiled from 500,000 acres, representing 150 grain farms that have management input from 73 AgriTrend (agronomists),” said Bills.

“The $35 per acre net gain is measured against a benchmark of acres fertilized with a flat rate. Seven dollars are realized through an input reduction by cutting back or eliminating fertilizer in areas with low yield potential. The other $28 comes from higher yield through better management of those areas with high yield potential. These are all real numbers from real farms we work with.


“In another case example we’ve worked out, a 7,578 acre farm can save $64,792 per year by reducing or eliminating fertilizer in two low productivity areas. That’s a risk reduction figure in fertilizer savings only. It doesn’t include yield increases. The concept of precision zone management we show in these examples isn’t difficult to understand. You just need training in how to do it.”

Bills’ one-hour webinar may have seemed elementary for the one-in-four prairie producers who already practise zone management, but he said it is geared for those growers who are still sitting on the fence.

The power zone concept is one of the basics for novices who are just starting out with an AgriTrend agronomist.

Bills recommended that farmers think of their fields in a top down, bottoms up format. The Agritrend model has six above-ground factors and six below-ground factors, all of which feed into the process of creating zone management prescription maps.

The company’s above ground approach considers information from satellites, airplanes, yield maps, ground truthing, NDVI sensors and tissue samples, while below ground factors include soil electric conductivity, such as EM38 and Veris profiles, grid soil samples, government soil surveys, slope positions, elevation maps and zone soil samples.

“(It) assesses variability above the surface. We look at plant density and all the things going on with the crop above ground, but it doesn’t tell us why. That’s the top down approach,” Bills said.


“Power zone is a cause and effect exercise. What happens above ground with the crop is an effect that’s caused by what happens down in your soil. With the bottom up approach, we deal with soil type, nutrition, moisture, salinity, topography, drainage, soil testing and all the other things that happen below ground. You need all the top down and bottom up factors.”

Bills said farmers’ awareness of the importance of salinity and EC testing has improved dramatically since the first Veris machine was displayed in Brandon 15 years ago.

“And the other thing that’s improved in recent years is the number of producers who are soil testing,” he said. “That’s a big step toward making better use of your land.”

For more information, contact Warren Bills at



  • Use your brain not your wallet

    It was found that zero till results in poorer crops and terrible soil management . Serious root zone compaction has resulted in the need for crazy priced vertical tillage tools to try and correct the damage created by zero till . Those who chose to stick with minimum tillage are the ultimate winners . When measuring the compaction after both types of soil management practices . Those who chose to try and cheat the system with zero till are now paying three times for trying to cut corners . 1 – crucial yield losses due to compaction in the vital root zone . 2 . The need for expensive vertical tillage tools to try and correct the problem . And three the increased use of chemical to control weeds has opened Pandora’s box on weed chemical resistance will the increased reliance on glyphosate and other chemicals . There are even shallow plows on the market to try and combat compaction . Yet those of us who chose a more knowledgable choice are reaping the rewards of higher yields , less reliance vertical tillage except where increased straw management from better crops . And last but not least less weed resistance as a balance of tillage and chemical control of weeds has been met . Now some company is going to tell me what I already know . The low spots on a dry year are going to yield more and thus require increased nutrients the following year and the opposite being true on a wet year . We have been manually adjusting rates with average shattering results for over 30 years . P.s . All our profits go where we need them . Not in some fly by night schemers pockets . Get with the program . Spend less make more . They hide things like that in books . Think about it , one day you will figure it out . 🙂 typed this on my iphone while Heavey harrowing , so don’t concentrate on how I wrote this , but rather ,what I wrote !!

    • P_B

      Not sure where you get that no-till creates compaction. However, no-till is not just a practice, it is a system. Many people who single pass seed do not have an adequate rotation. And going into a field too early is going to cause problems for anyone. You are right – light tillage can hide some of that, though I have looked at enough aerial photos to see the tractor tire stripes in all directions on conventional/min-till fields to know that it may look good from the road but from the air! In the program I teach I encourage farmers to build their own zone maps. Between yield monitors and easily accessible satellite imagery, and farmer knowledge, most guys can do it with a little practice. Being comfortable spending time in front of a computer and then being willing to invest in a soil testing rig are the two biggest drawbacks I see.

    • Huge farms !!!

      Wow , I think you hit the nail on the head . On our farm we have spent hundreds of thousands on some of this , as you call it ” fly by night ” schemers technology . Every other year it becomes worthless and the money is gone . We are worse off as the money can never be recovered . For example , this is our fourth type of auto – steer system that we have incorporated into All our farm equipment . Sprayer , air-drill , swather and combine . We were able to sell the last few systems to try and off set the costs . But the new systems cost us a fortune . We calculated 15 years of use just to pay for the system , before we actually see a return . With misses in the fields , grain left standing and sometimes weeds left untouched , would make my dad role over in his grave . Not to mention , everytime the bride brings out supper , “can’t you fix that so we don’t have grain left standing all over all the fields . 15 thousand for each unit . Yikes 5 air drills , 3 sprayers , 9 combines , and 6 swathers . There went last years profit !!! . We try and transfer a few units , but we are pre harvesting , swathing And combining all at the same time . Kinda tough to skimp there . Oh yah , I forgot that stupid grain cart . This is the fourth one of those . The auto steer system failed last year and the tractor totalled a 85 thousand dollar header . No insurance covers that guy’s . So pray it doesn’t happen to you !!! Anyway , we ready Togo back to the old ways . We dumped on the go and we never had a mishap until auto -steer came along . We are fighting with the company . But we know we won’t get anything . Although , we aren’t going to give up ! . So as far as this variable rate . Stick it where the sun don’t shine . We are fed up , giving our hard earned money away !!!