February 12, 2013

Agronomists Notes

Hello Reader,

Just one week until I leave for Australia and New Zealand and the itinerary is really shaping up. I’m visiting with some top producers in South Australia and Queensland looking at precision farming applications and controlled traffic farms. The last leg of my journey includes a stop in New Zealand where some 230 bu/ac wheat is being taken off as we speak.

In this week’s issue of Beyond Agronomy News, we’ll look at pushing wheat yields through split applications of nitrogen and fungicides where one plus one equals three, and it’s not my wonky math. Next, I’ll discuss our desire to move into variable rate, side dress nitrogen applications in narrow row cereals and oilseeds. We’ll finish with technical grain market news.

Have a great week.

Pushing wheat yields with split apps of nitrogen & fungicide

One + One = Three times the yield

I had the pleasure of taking in Peter Johnson’s presentation on breaking the wheat yield barrier at FarmTech recently. WheatPete is his Twitter handle and he is Ontario’s provincial wheat specialist and an entertaining speaker. He discussed the importance of pushing wheat yields through proper seeding depth, residue management, seed treatment and multiple applications of nitrogen and fungicide. On farm-scale trials in Ontario they were able to achieve a winter wheat yield of 188 bu/ac! Today, we’ll focus on the use of multiple fungicides and nitrogen applications, a technique long used by the European’s and record setting Kiwi’s.

Fungicides
As we all know, fungicides play a significant role in managing disease but they also have the ability to delay senescence, which keeps plants healthier and alive longer. Fungicides do this by altering the microflora on plants that normally play a role in leaf senescence or retard the breakdown of chlorophyll biochemically. The end result is a plant that is able to utilize additional inputs like nitrogen later in the growing season. In New Zealand I discovered that every day you delay natural senescence you add 250 kg/ha to yield in wheat. For the imperial folks that’s 3.7 bu/ac per day!

In order to generate a long lasting stay green effect, fungicides should be applied at two stages, flag leaf and flowering. The flag leaf application provides protection from leaf disease and the application at flowering not only protects against head diseases but also helps delay senescence at a time when plants are aging more quickly and more prone to dying off.

Now to deflate the excitement about fungicides somewhat, Peter Johnson’s research found an average 7% yield increase in winter wheat whether applied at flag or at flag plus flowering. It’s still impressive and his research increased wheat yields from 93 bu/ac to 99 bu/ac. However, the real magic happened when he combined the stay green effects from multiple fungicides with split applications of nitrogen.

Nitrogen
The list of research explaining the benefits of split applications of nitrogen is long. We know that delaying nitrogen timing avoids excessive vegetative growth, reduces nitrogen immobilization and allows nitrogen to become available during the critical reproductive phase. In Peter Johnson’s research, he found an average 7% yield increase when split applying UAN 28-0-0 with streamer nozzles at nitrogen rates up to 150 lbs N/ac without using fungicides.

I won’t go into detail about specific strategies on split applying nitrogen but I will include an excellent summary from fellow Nuffield Scholar Richard Heath from Australia. Richard summarizes the split app strategies used in England, US, Canada and Australia. (Beginning on page 7.)

Fungicides + Nitrogen
So, if you add a 7% yield increase from fungicides with a 7% yield increase from split applying nitrogen, you should see a 14% yield increase right? No, actually. When you combine multiple fungicides with split apps of nitrogen the yield increase becomes more like 20%! As Peter explains, one plus one does not equal two, it equals three. Combining the two strategies is when the magic happens.

The chart above outlines the results of Peter’s research from 2008-2010. Following the numbers marked in red, you can see no fungicide and 90 lbs N achieved 93 bu/ac. The addition of 30 lbs of N generated a yield of 105.1 bu/ac. Adding two fungicides plus 150 lbs of N produced a total of 111.1 bu/ac. In 2009 the same 150 N plus two fungicides produced 9 bu/ac more than the same treatment with only one fungicide. Let’s run the numbers to make some sense of the risk reward offered with two fungicides and split applications of nitrogen.

I won’t get tied up with nitrogen rates here. I’ve done the Steve’s quick math and can tell you that even the 150 lbsN/ac with two fungicides netted the highest margin but by a small amount. Okay, here goes.

Steve’s quick math: Wheat $8.00 bu, $0.65 lb N
90N: $744.00/ac - $58.5 N/ac = $685.50/ac
120N + 1 Fungicide: 105.1 bu/ac x $8.00/bu – $78.00 ac/N - $10 Fungicide = $752.80/ac
150N + 2 Fungicides: 111.1 bu/ac x $8.00/bu – $97.50 ac/N - $20 Fungicide = $760.00/ac

The key is to remember that in order to maximize the gains of split applications of nitrogen, the plant must be kept healthy to generate the yield benefit. A plant that is dying off prematurely does not have the photosynthetic capacity to utilize the additional nitrogen. Most split application nitrogen trials have never looked at the combination of fungicides with nitrogen. The same applies with multiple fungicides; they are never in conjunction with additional nitrogen to realize the benefit of the two systems together. So, the next time you’re pushing high N rates in wheat, remember to focus on keeping the plants healthy. Only then will you realize the full potential of either input. Perhaps this information will help you take yields to the next level. Well done, Pete. SL

Research results of nitrogen and fungicide on wheat by Peter Johnson, 2008-2010. Special mention to Canadvance, Grain Farmers of Ontario, and Dr. David Hooker.

Making the move to variable rate side dress nitrogen

Mitch and I are planning our next move to apply variable nitrogen in-season to manage risk and capitalize on the additional yield inside our inter-row seeding, controlled traffic system. We have the capacity to generate a tremendous amount of nitrogen use efficiency by side dressing nitrogen between the rows using GreenSeeker technology to vary the rate across the landscape real-time. Just saying the phrase variable rate, inter-row, side dress nitrogen inside a CTF system makes me giddy. Here’s the scoop.

There are many benefits to split applying nitrogen but the system is not always efficient for two reasons. One, split applications are completely dependent on rainfall after application whether you use a liquid like UAN or a dry product like urea. Rainfall is needed after application to wash nitrogen into the soil where roots have access. Second, applying UAN or urea on the surface leaves it susceptible to immobilization and volatilization, especially in high residue systems. The microbes that feed on residues require nitrogen to build protein and can immobilize up 40% of your applied nitrogen. Nitrogen applied to the surface as UAN (50% urea) or prilled urea can be lost as a gas through volatilization.

So how do you eliminate the two biggest risks? You put it in the ground!

Producers in the corn belt have known for a long time that placing nitrogen in the ground is more efficient than broadcasting or streaming nitrogen on the surface. They also know that split applying nitrogen is a more efficient way to deliver nitrogen at the right time. Mitch and I plan to take that concept and apply it to our narrow row, wheat, barley and canola production. We have a unique opportunity to apply variable rate nitrogen between the rows using coulters on a side dress toolbar outfitted with our GreenSeeker because of our inter-row, CTF system.

We are looking at a 60-foot toolbar with coulters spaced every 24 inches. This would act like a mid-row band concept where 2 rows are fertilized every 24 inches, so each row has access to nitrogen on our 12-inch row spacing. The complete toolbar we are looking at is made by FAST and can come with widths out to 90 feet. In our 30-foot CTF system, we will use a 60-foot toolbar and run on every second pass to stay on our trams. The cost of the unit, which includes 20-inch coulters on 24-inch spacing, a 60-foot boom made with 7-inch square tubing and an 1,800 gallon tank is $65,000. See a link to the FAST 8100 model here and a video of one in action here.

The way I see it, we have an opportunity to seriously improve nitrogen use efficiency through side dress variable rate nitrogen applications. For example, we can apply a base rate of 90 lbs/N/ac in cereals and 100 lbs/N/ac in canola. Spring crops like wheat, barley and canola still need a serious amount of nitrogen early on. We’ll use the GreenSeeker and side-dress toolbar to apply the rest of the nitrogen to match crop conditions and soil moisture. At the end of the day we’re looking at a probable maximum of 30 lbs/N/ac average to side dress N for a cost of $21.00/ac plus application at $0.70/lb nitrogen.

Most farms today are running very efficiently with their sprayers and adding a liquid nitrogen application in-season is not logistically possible. Setting up a 60 or 90-foot side dress toolbar pulled by a front wheel assist tractor that is typically not in use at this time of year is more likely. Side dressing nitrogen reduces the risk of putting all nitrogen up front, allows you to capitalize on applying more when the season is favorable, add a GreenSeeker and you can apply it in the right place and most of all, reduce the risk of low rainfall and immobilization after application where most split applications of nitrogen fail. I’ll keep you posted on our progress. SL

For more info on the FAST 8100, 8200 and 8300 side dress toolbars, visit R.A. West International Ltd. the dealer out of Vulcan, Alberta.

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