March 19, 2013

Agronomist Notes

Hello Reader

I had an excellent time catching up with the 2013 Nuffield Scholars at this year’s Contemporary Scholars Conference in Niagara Falls. I had the privilege of closing the week long conference by telling my story and my Nuffield journey. There are 80 Scholars from around the world with many from Australia, New Zealand, England, Scotland, Ireland, Brazil, France and the US. I was inspired to be surrounded by so many people who are passionate about agriculture. Surround yourself with good people and great things happen. That’s Nuffield.

This week I’ll be breaking down the optimal timing and windows for split applications of nitrogen in wheat. Next, I’ll provide you with the 2012 CTF project report. We’ll finish with technical grain market news.

210 bu/ac soft white winter wheat crop of Mike Solari’s. Current Guinness World Record holder for wheat yield.

Breaking down split N applications in wheat

Lightening speed required

We’ve been looking at split applications of nitrogen and the growth stages at which top producers around the world apply nitrogen to maximize yield. After walking through 178 bu/ac HRS wheat and measuring 60 kernels per head, I had to take another look at how we can manipulate wheat yield with split applications of nitrogen. To build yield in wheat it’s very important to understand the growth stages where yield is derived, then work towards a strategy that supplies plant available nitrogen at the right rate, right place, right form at the right time.

Dr. Dave Hooker from U of Guelph provided me with an excellent slide showing the growth stages of wheat where we can build yield. We’ll look at the optimal window to apply nitrogen and look at nitrogen rates to produce high yielding wheat.

The best way to view the wheat yield chart is here on our website.

The wheat development timeline chart outlines four key growth stages where yield is built:

1) Tillering GS 20-30: number of heads
2) Stem elongation GS 30-40: number of spikelets per head
3) Flowering GS 60: kernels per head
4) Grain fill GS 60-90: kernel weight

The stage I would like to focus on today is stem elongation, which starts at the end of tillering (GS 30) and ends at the boot stage (GS 40). It is this stage where nitrogen demand is highest and wheat yield can be influenced the most. Stem elongation is a critical growth stage because of the tremendous amount of cell reproduction that occurs. The wheat plant is building new cells as stems grow taller and thicker, leaves grow longer and wider and new spikelets are being produced on each head, which means up to six sets of male and female parts per row. All this requires a tremendous amount of nitrogen, water and carbon dioxide. A deficiency in any one of these at this time equals a loss in yield. We’ll focus on what we can control for now, and that’s nitrogen.

On average, spring wheat will move through tillering (GS 20-30) in our area within about 25 days depending on temperatures. Wheat will move from stem elongation to boot stage (GS 30-40) within about 7 to 10 days depending on temperatures. The reason wheat moves so quickly from stem elongation to boot stage is because it occurs just after the summer solstice, which combines warm temperatures with our longest daylight hours. At 52 degrees latitude, we have 18 hours of daylight each day during this critical growth period. That means cell division is happening at a greater pace than other countries and latitudes experience during this growth stage.

To be successful with split applications you have to apply a nitrogen form that is available or becomes immediately available to get it into the plant quickly. This is why broadcasting urea or streaming UAN on the surface is hit and miss. You have just 7 to 10 days to get nitrogen into the plant and without timely rainfall, you’ll miss the optimal window. Applying nitrogen too early at mid-tillering may generate excessive tillering and not necessarily more kernels per head. Too late and you’ll generate protein and not yield. This is one of the reasons Mitch and I are moving to a side-dress nitrogen unit where we can put nitrogen in the ground where plants have immediate access.

The research suggests that we apply 33% of our nitrogen needs prior to tillering and 66% just prior or during stem elongation to maximize yield. Unfortunately, if your applying nitrogen on the surface, you may only generate 65% nitrogen use efficiency. Nitrogen can become immobilized or volatilize when applied to the surface, which is where you lose efficiency. This means you need to apply 33% of your N prior to tillering and 66% + 35% at stem elongation to make up for the nitrogen lost. A little Steve’s quick math is in order.

Yield target: 120 bu/ac HRS
120 bu x 2.2 lbs/N/bu targeting 12% protein for optimal yield = 264 N/ac
Soil N + OM mineralization on 4% OM: 35 N/ac + 28 N/ac = 63 N/ac
Total N applied: 264 N – 63 N = 201 N/ac
Tillering N app: 201 N x 33% = 66 N/ac
Stem elongation N app: 201 N x 66% = 132 N/ac

In this scenario we would need to apply 63 lbs/N/ac prior to tillering and 132 N/ac at stem elongation. If we factored in a N use efficiency of 65% we’d have to apply 203 lbs/ac to achieve 132 N/ac of plant available nitrogen. That’s a potential 71 lbs/N that's lost when surface applying nitrogen. Again, another reason to move toward side dressing and getting that nitrogen in the ground.

In the end, top producers from around the world are able to manipulate wheat yield by applying significant amounts of nitrogen at stem elongation. The 178 bu/ac HRS wheat crop I walked through two weeks ago in New Zealand had 60 kernels per head vs the 30 per head we normally achieve here. Split application works. In W Canada, our challenge is to figure out how to get nitrogen inside the plant during the 7 to 10 day window. Side dressing nitrogen into the soil, close to the roots with liquid nitrogen is our strategy. Right time, right place, right rate, right product. Stay tuned for our results in 2013.

Source: David Hooker, University of Guelph

2012 CTFA project report

CTFA cooperator adoption rate 100%

Peter Gamache, the project lead for CTF Alberta has released the 2012 CTF report, which outlines the results of our cooperator trials. I’m very pleased to announce that three out of the four cooperators are making the switch to move to full CTF in the coming years. The fourth cooperator is already on the path. These farms range in size from 2,500 to 10,000 and they are all in after discovering the opportunities that CTF presents.

To find out more on the cooperator sites, soils, yield, economics and more go to CTF 2012.